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... Salicylic acid and its derivatives are constituents of various natural products comprising the phenolic group with numerous therapeutic effects. 1 The simplest derivative, Oacetyl salicylate, also known as aspirin, is a nonsteroidal antiinflammatory drug (NSAID). 2 Salicylic acid-conjugated amino acids/peptides are also explored in the development of novel drug candidates. The amide derivatives of salicylic acid, salicylamide (SAM), possess analgesic and antipyretic properties. ...
... Compound 2a was synthesized by the abovementioned procedure and purified by column chromatography with solvent system ethyl acetate/hexane (12:88) as a colorless gummy compound (86% yield). 1 Methyl (2- Hydroxybenzoyl)-L-alaninate (2b). Compound 2b was synthesized by the abovementioned procedure and purified by column chromatography with solvent system ethyl acetate/hexane (15:85) as a white solid (84% yield). 1 Methyl (2-Hydroxybenzoyl)-L-leucinate (2d). ...
... Compound 2b was synthesized by the abovementioned procedure and purified by column chromatography with solvent system ethyl acetate/hexane (15:85) as a white solid (84% yield). 1 Methyl (2-Hydroxybenzoyl)-L-leucinate (2d). Compound 2d was synthesized by the abovementioned procedure and purified by column chromatography with solvent system ethyl acetate/hexane (10:90) as a white solid (81% yield). 1 169.5, 161.3, 155.8, 149.0, 137.0, 134.3, 126.3, 122.6, 122.1, 118.8, 118.3, 114.2, 48.9, 44.5, 18.9. ...
An organic acid, salicylic acid, and its derivatives are constituents of various natural products possessing remarkable bioactivity. O-Acetyl salicylate (aspirin) is a well-known life-saving drug. Its peptide derivative salicylamide has also been explored in the designing of peptide-based therapeutic drugs. An organic base, picolylamine has been recently explored for designing diagnostic probes. However, both the acid and base have common features as metal chelating with coordinating metals. Thus, these scaffolds could be used for designing inhibitors of various metalloenzymes. Their characteristic properties encourage us to design peptides containing both scaffolds (salicylic acid and picolylamine) at opposite terminals. So far there is no report available on such conjugated peptides. This report describes the synthesis, conformational analysis, and biochemical assessment of rationally designed N-salicyl-AAn-picolamide peptides. Pleasantly, we have obtained the crystal structures of representative peptides that confirm their roles in conformational changes. Our biological assessment as quorum sensing inhibitors has revealed that their di/tripeptides inhibit quorum sensing of the pathogenic bacterium PA14 strain. Hence, these peptides have promising foldameric and therapeutic values.
... It has the potential to improve cell prolifera- tion, senescence gene expression, and fruit output (Klessig et al. 2009;Kazem et al. 2020;Rao et al. 2021). Salicylic acid is crucial for enhancing environmental stress resistance (Raskin 1992;Liu et al. 2022) such as salinity tolerance (Jam et al. 2012;Farhangi-Abriz and Ghassemi-Golezani 2018;Hongna et al. 2021;Hamayun et al. 2022;Kumar et al. 2022), water-deficit tolerance (Bezaukova et al. 2001;Lee et al. 2019;Abbaszadeh et al. 2020;Ahmad et al. 2021;Khalvandi et al. 2021;Safari et al. 2021;Shemi et al. 2021), and low and high temperature tolerance (Khan et al. 2010;Ignatenko et al. 2019;Afzal et al. 2020;Wassie et al. 2020;Yang et al. 2022). Similarly, SA plays a role in plant physiological activities such as stomatal control, food uptake, chlorophyll and protein synthesis, ethylene biosynthesis inhibition, and photosynthesis (Raskin 1992;Cheng et al. 2016;Jahan et al. 2019). ...
... Salicylic acid is crucial for enhancing environmental stress resistance (Raskin 1992;Liu et al. 2022) such as salinity tolerance (Jam et al. 2012;Farhangi-Abriz and Ghassemi-Golezani 2018;Hongna et al. 2021;Hamayun et al. 2022;Kumar et al. 2022), water-deficit tolerance (Bezaukova et al. 2001;Lee et al. 2019;Abbaszadeh et al. 2020;Ahmad et al. 2021;Khalvandi et al. 2021;Safari et al. 2021;Shemi et al. 2021), and low and high temperature tolerance (Khan et al. 2010;Ignatenko et al. 2019;Afzal et al. 2020;Wassie et al. 2020;Yang et al. 2022). Similarly, SA plays a role in plant physiological activities such as stomatal control, food uptake, chlorophyll and protein synthesis, ethylene biosynthesis inhibition, and photosynthesis (Raskin 1992;Cheng et al. 2016;Jahan et al. 2019). SA is implicated in disease-curing pathways after pathogen attack (Alvarez 2000;Liu et al. 2020). ...
... The role of salicylic acid may be due to its positive affects the activity and viability of plant cells, leading to the increase in plant growth. It also affects plant physiological processes as well as having anti-disease functions, and hence promotes plant growth (Raskin 1992). The increase in vegetative growth upon SA treatment may be due to its role in increasing the cytokinins, which play a role in reproducible cell division (Khan et al. 2010), and in raising the efficiency of photosynthesis by increasing CO2 absorption in plastids, thus providing the materials needed for budding (Khan et al. 2010). ...
Common beans are very significant for poor countries, because they provide high nutritional value, especially in terms of protein, calories, and trace nutrients, to people who cannot afford more expensive forms of nourishment. The current experiment was performed to investigate the influence of four different levels of organic fertilizer (compost) in the presence of mineral N fertilizer, i.e., T1: 25% M‑RDN +75% O‑RDN; T2: 50% M‑RDN +50% O‑RDN; T3: 75% M‑RDN +25% O‑RDN; and T4 (control): 100% M‑RDN (O-RDN, M‑RDN = recommended dose of N in organic and mineral forms, respectively; RDN: 60 kg N/fed.) and foliar spray with salicylic acid (SA) at 0, 50, 100, and 150 ppm, as well as of their interaction, on vegetative growth, productivity, and seed quality of common bean (Phaseolus vulgaris L.) cv. Nebraska. Obtained results showed that the tallest plants, the highest number of branches per plant, and the heaviest leaf fresh and dry weight per plant were scored using the combined treatment comprising T4 (100% M‑RDN) and SA at 150 ppm in the two seasons. T4-fertilized and 150 ppm SA-sprayed plants induced the highest values of leaf N, P, K, and total carbohydrates (%). The highest seed yield per plant and hectare as well as the highest average weight of 100 seeds were achieved by plants fertilized with T4 or T3 treatments (75% of M‑RDN +25% O‑RDN) and sprayed with 150 ppm SA in the two seasons. The combined treatment of T4 and SA at 150 ppm caused the statistically highest values of seed N%, P%, total protein (%), K%, and total carbohydrate (%). In addition, the lowest values of seed nitrate content were achieved by plants fertilized with the T1 treatment (25% M‑RDN +75% O‑RDN) and receiving 150 ppm SA foliar spray. In conclusion, for enhanced growth, productivity, and quality of common bean plants, it could be safe to fertilize with 75% M‑RDN +25% M‑RDN and spray these plants with SA at 150 ppm.
... Among the different signaling molecules in plants, SA is an important molecule that is known to play a role in stress response (Raskin, 1992;Arfan et al., 2007;Lee et al., 2018). SA signaling regulates stress by influencing photosynthesis (Khan et al., 2012). ...
... We show that pretreatment of the Chinese cabbage seedlings with SA rescues the negative physiological responses while positively impacting the phenotype of the seedlings. This might be caused by altered signal transduction following exogenous SA treatment (Raskin, 1992). SA plays an important role as a signaling molecule in seedlings, which induces antioxidant activities, alleviates lipid ...
... Among the different signaling molecules in plants, SA is an important molecule that is known to play a role in stress response (Raskin, 1992;Arfan et al., 2007;Lee et al., 2018). SA signaling regulates stress by influencing photosynthesis (Khan et al., 2012). ...
... We show that pretreatment of the Chinese cabbage seedlings with SA rescues the negative physiological responses while positively impacting the phenotype of the seedlings. This might be caused by altered signal transduction following exogenous SA treatment (Raskin, 1992). SA plays an important role as a signaling molecule in seedlings, which induces antioxidant activities, alleviates lipid ...
... Acetylsalicylic acid (ASA, 2-acetyloxy-benzoic acid; an artificial analogue of SA) and resorcylic acid (2,6dihyroxybenzoic acid) have shown thermo genic activity comparable to SA (Raskin et al. 1989) [51] . Flowering in these plants can also be stimulated by benzoic acid (Raskin 1992) [49] . The involvement of SA in the induction of systemic acquired resistance (SAR) is a topic of intense research (Sticher et al. 1997) [63] . ...
... Acetylsalicylic acid (ASA, 2-acetyloxy-benzoic acid; an artificial analogue of SA) and resorcylic acid (2,6dihyroxybenzoic acid) have shown thermo genic activity comparable to SA (Raskin et al. 1989) [51] . Flowering in these plants can also be stimulated by benzoic acid (Raskin 1992) [49] . The involvement of SA in the induction of systemic acquired resistance (SAR) is a topic of intense research (Sticher et al. 1997) [63] . ...
... It was also found that Salicylic acid have the ability to improve protection of plants from disease, it can be used to reduce the application of chemical fungicides by inhibiting the enzyme catalase, which subsequently increases hydrogen peroxide H 2 O 2 and this increase in plant biosynthesis is a fungicide. (Raskin, 1992;Dihazi et al., 2003;Cao et al., 2006;Babalar et al., 2007). Salicylic acid encourage or inhibit physiological processes in fruits and increment the protein within the plant cells so increased the capability to tolerant of salt stress ( Kumer et al.,1999). ...
... So, increasing fruit set and retention resulted in increasing the bunch weight and total yield. The increment in fruit set and consequently bunch weight and total yield by salicylic acid application may be due to its effect on enhancing photosynthetic activity in the leaves and translocation photo assimilates to fruits and stimulates cell division and increased tolerance of plants to any stresses like salt stress, water, diseases and protects the cells from oxidation caused by the free radicals (Raskin, 1992;Lee et al., 1995 andShah, 2003). These results are in harmony with those obtained by (Singh et al., 2003 andNgullie et al., 2014) and (Ahmed et al., 2015a andRahmani et al., 2017) indicated that application of salicylic acid at 2.5 g/l recorded the highest fruit retention, number of fruits and total yield per tree. ...
Abstract
This investigation was conducted at private orchard located at new Assiut
city, Assiut, Egypt, during 2020 and 2021 seasons on Sewy date palm grown in
sandy soil, to investigate the effect of spraying silicon(potassium silicate) at (2 and
3 cm3
/L) and salicylic acid at (2 and 3 g/L) on yield and some physical and
chemical fruit properties. The foliar spraying for all treatments were done three
times during the season, the first spray was done at beginning of spathes appearing.
The second one was applied after fruit setting finally the third one was applied
after one month later. The control was sprayed with tap water. The results indicated
that spraying silicon (potassium silicate) and salicylic acid was very effective on
increasing yield, bunch weight and some physical and chemical fruit
characteristics compared to the control. The enhancing associated with the high
concentration of such spraying substance. Moreover, Salicylic acid was superior
to Silicon in this respect which gave the best results of this study compared with
the other investigated treatments.
Keywords: Silicon, Salicylic acid, Potassium, Sewy date, Yield
... Salicylic acid (SA), is a phenol-derivative compound which is widely distributed in plants (Chen et al. 2009) and it is well known to regulate pivotal physiological and biochemical processes including plant signaling, plant defense and response to biotic and abiotic stress (Wani et al. 2017;Sharma et al. 2020b). SA can be isolated in plants in its free and conjugated forms, for example methylated, hydroxylated and/or glucosylated (Raskin 1992). Salicin, one of the natural SA derivatives, was firstly isolated from the bark of the willow tree (Salix sp.) by Johan Büchner in 1828 (Arif and Aggarwal 2020;Shine et al. 2016). ...
... Besides the "direct" role of SA in plants subjected to salt stress, SA interplays with other phytohormones and signaling molecules in salt-stressed plants (Munir et al. 2016;Raskin 1992). Figure 2 reports a schematization of some possible interactions between SA and other biomolecules. ...
Salicylic acid (SA) has multiple functions in plants, either under optimal or environmental stress conditions. In salt-stressed plants, SA in coordination with other plant hormones (e.g., auxins, abscisic acid, gibberellins) and other signaling molecules can take part to the finely tuned regulatory network, to promote the stimulation of plant defenses aimed at counteracting the salt-triggered harmful effects. This review summarizes the most updated literature dealing with the roles of SA in salt-stressed plants with the aim to provide a comprehensive picture about physiological, biochemical and molecular mechanisms mediated by SA during salt stress, to highlight the possible beneficial effect of SA supplementation and to orientate the direction of future research on this topic.
... Salicylic acid (SA) is an endogenous plant hormone of phenolic nature that posses an aromatic ring with a hydroxyl group and plays a vital role in plant growth, ion uptake and transport (Hayat et al. 2010). SA a natural inductor of thermogenesis, are known to induce flowering in a range of plants, control ion uptake by roots, photoperiodic responses, senescence mediation and stomatal conductivity (Raskin 1992). It has been reported to mitigate the deleterious effects of several environmental stresses on plants including low temperature and chilling, high temperature and drought (Senaratna et al. 2000), and salinity (Yildirim et al. 2008), increase tolerance and defence to pathogen attack (Raskin et al. 1990). ...
A field experiment was conducted at Agricultural Research
Farm, Pandit Deen Dayal Upadhyay Institute
of Agricultural Sciences, Utlou, Bishnupur District,
Manipur, India during the year 2018-2019 to study
the effect of salicylic acid and potassium nitrate on
yield, economics nutrient uptake and quality of lentil under rainfed
conditions. The findings indicated that seed priming
of salicylic acid (SA) @ 200 ppm and scaling up
of potassium nitrate (KNO3) up to 1.5% as foliar
application significantly enhanced the yield (grain
yield, stover yield and biomass yield) and economics,
nutrient uptake and quality of lentil. The treatment
combination salicylic acid @ 200 ppm + KNO3 1.5%
gave the maximum grain yield (1104.88 kg/ha), stover
yield (1799.06 kg/ha) and biomass yield (2903.95 kg/
ha). The gross returns (₹73617), net returns (₹38729)
and benefit:cost ratio (2.11) were highest through
application of SA @ 200 ppm and KNO3 @ 1.5%.
The N, P and K uptake (kg/ha) and protein content
of lentil were highest through application of SA @
200 ppm and KNO3 @ 1.5%.
... Salicylic acid (2-hydroxybenzoic acid; SA) has been shown to play an important role in several physiological processes in plants, including heat production, flowering, and germination [1,2]. The role of SA in pathogen resistance has been studied extensively in the last two decades [3,4]. These studies have demonstrated that the accumulation of SA is related to the full expression of resistance to some pathogens, leading to alterations in mitochondrial function and changes in gene expression. ...
A simple and inexpensive capillary zone electrophoresis (CZE) with UV detection method was used to determine salicylic acid (SA) and six structural analogs (benzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, acetylsalicylic acid, methyl salicylate, and jasmonic acid). All of the compounds were successfully separated within a migration period of 6 min, with a high number of theoretical plates (>37,000, calculated using the width at the base of the SA peak), in 20.0 mmol L ⁻¹ Na 2 HPO 4 /H 3 BO 3 buffer (pH 9.0) containing 2.0% methanol and 2.0% acetonitrile. The regression line for SA was linear over the range 0.5–200 µmol L ⁻¹ . Both the intra- and inter-day precisions of the migration time (relative standard deviations, RSDs, 0.6% and 4.7%, respectively) and peak area (RSDs 0.9% and 7.3%, respectively) were acceptable. The proposed method was used to determine the SA concentrations in tobacco leaves ( Nicotiana tabacum L.) from the Xanthi-nc ( NN genotype) and the Nt-NahG mutant strains that had been irradiated with UV (254 nm) for 20 min and the ones that had not been irradiated. Rapid separation (<6 min), good reproducibilities (RSDs < 11.9%), and good recoveries (94.7–118%) were obtained in the tobacco leaf analyses.
... Several studies performed with rhizosphere bacteria show that most strains produced metabolites of the AIA type, siderophores and salicylic acid (22). Salicylic acid (SA) is a phenolic secondary metabolite (20) present in plant tissues (33,41), regulating plant growth and increasing crop yield when supplied in low exogenous concentrations (34). In maize, the application of SA increases grain production per plant, total dry biomass, and N, P, K contents (41). ...
Salicylic acid and Azospirillum brasilense stimulate plant growth and productivity. In some environments, plant physiology similarly responds to both bioactive products. Considering this, a field experiment was conducted to study the physiological effect of Salicilic acid and A. brasilense on growth and grain yield of maize plants. The experiment involved three treatments consisting of imbibed seeds in an aqueous solution of SA (0.01 mM), inoculated seeds with A. brasilense and a control treatment. Seed imbibition in SA and inoculation with A. brasilense improved vegetative growth in the early stages of crop ontogeny, increasing leaf growth, plant height, stem diameter and biomass accumulation. Spikelet length and weight were greater in plants first inoculated with A. brasilense and then treated with SA. Results indicated that SA stimulated biomass partitioning towards leaves, root and stem, while A. brasilense mainly affected leaf growth, plant height, ear dimensions and grain yield. Such results turn crucial for biological fertilization strategies aimed at reducing pollutant loads that accompany chemical fertilizers. Both products can be part of maize management practices given competitive economic advantages and sustainability.
Highlights:
• Seed imbibition in SA and inoculation with brasilense improved vegetative growth in the early stages of crop ontogeny, increasing leaf growth, plant height, stem diameter and biomass accumulation.
• Salicylic Acid stimulated biomass partitioning towards leaves, root and stem in maize plants.
• Azospirillum brasilense stimulates leaf growth, plant height, as well as ear dimensions and grain yield in corn plants.
... Secondary metabolites, including major groups such as phenols and flavonoids, also aid plant interactions with their surrounding environment (Hartmann, 2007). Studies have demonstrated that some phenol metabolites, such as salicylic acid, play a crucial role in allowing plants to resist biological stresses (e.g., soil insect pests) and abiotic stresses (e.g., drought and extreme cold) (Raskin, 1992;Wani et al., 2016). Additionally, some flavonoids, such as quercetin, assist in plant anti-oxidation and water and nutrient transport (Hartmann, 2007;Hara et al., 2012). ...
Root exudates play an important role in nutrient acquisition and defense of trees. However, there are few studies on the mechanism of productivity decline in late stage from the perspective of root exudates. Therefore, we collect root exudates in the summer and winter from 8-year-old (young), 18-year-old (middle-aged), and 49-year-old (overmature) trees in Chinese fir plantations to assess how their exudation rates and metabolite composition changed across these different life stages. Results showed that the rates and metabolite composition of root exudation varied significantly across plantation ages and between seasons. Specifically, the young Chinese fir trees increased exudation rates and produced more carbohydrates and quercetins, and overmature trees secreted more lipids and salicylic acids. This indicates that young Chinese fir plantations adopted root metabolic strategies which increased nutrient acquisition to satisfy the demands of rapid growth, but overmature plantations might produce more defensive metabolites to improve their defense capabilities. Additionally, in the winter, trees had slower root exudation rates and released a smaller proportion of organic acid, carbohydrate, and quercetin metabolites than in the summer, but a greater proportion of lipid and salicylic acid metabolites. We also found that soil microbial factors (microbial community composition and diversity) had a significant effect on the composition of primary and secondary metabolites in the winter. Overall, as plantation age increased, Chinese fir root metabolic strategies related to nutrient acquisition decrease, while those related to defense increase. These findings provide a new perspective for our understanding of the mechanisms that lead to productivity declines of Chinese fir plantations in later growth stages.
... It is present in plant either as free phenolic acid or as a conjugate form that is produced by glucosylation, methylation or hydroxylation of the aromatic ring. 128,129 The synthesis of SA occurs in plants via two pathways, in which chorismate is used as a primary metabolite. In one pathway, chorismate is converted to isochorismate by isochorismate synthase that is further catalyzed by isochrismate pyruvate lyase to salicylic acid. ...
Ethylene, the gaseous ripening hormone, notably influences the postharvest physiology of the fruit. The pronounced effect of ethylene on postharvest physiology ranges from beneficial to unacceptable, with substantial commercial repercussions. Climacteric fruit undergoes an ethylene burst with the onset of ripening, and this autocatalytic ethylene production leads to accelerated ripening and senescence of fruit. Thus, the fruit becomes soft, mealy, and prone to pathogen attack that ultimately leads to high postharvest losses during handling, storage, and marketing. The key to appropriate handling, storage, and marketing of fruit lies largely in the successful management of ethylene. Biological interventions such as gene silencing, gene editing and recently the gene modifications through CRISPR/Cas9 are widely accepted and being used to regulate ethylene in fruit. Nevertheless, postharvest interventions and use of novel molecules such as 1-MCP, polyamines, salicylic acid, and ozone have received commercial status for controlling ethylene action in fruit. Use of metal-based catalysts at low temperature has been considered as a safer approach. This review focuses on the history, biosynthesis, action mechanism and techniques employed for useful modulation of ethylene biosynthesis and action in harvested fruit.
... The increment in total phenolic content under the high concentration of salicylic acid (200 ppm) may be due to the phenolic nature of salicylic acid [76]. This rise in the phenolic content may be one way that salicylic acid helps to lessen the suppressive effects of drought, as Table 6 Effect of irrigation (times per week) and salicylic acid (ppm) on essential oil production, total phenolics, and antioxidant activity of Hyssopus officinalis during 2018-2019 and 2019-2020 seasons phenols have perfect structural chemistry for free radical scavenging activity [52]. ...
... They are very beneficial for preventing free oxygen and reducing cell senescence, as well as protecting the cells from senescence. Moreover, they enhance the cell division and the biosynthesis of organic foods and control the incidence of fungal attack (Galala and Abdou, 1996;Elade, 1992;Raskin, 1992). Recently, using plant extracts, especially garlic, moringa, turmeric, etc, are considered a good alternative for improving date palms production through enhancing fruit quality and marketing. ...
... Salicylic acid is an important plant hormone that not only governs flowering growth, gender differentiation, stomatal movement, and photoperiod but also is a sufficient and necessary factor to induce pathogen defense responses (Raskin, 1992). Salicylic acid-mediated plant defense is an important defense route for plants to resist pathogens that are biotrophic or semi-trophic (Palmer et al., 2017). ...
The sunflower inbred line 33G was used as the experimental material, which was planted in the downy mildew disease nursery and the normal field, respectively, to examine changes in metabolites differences in metabolic pathways, and the mechanism of regulation of metabolic pathways in the process of sunflower susceptible to downy mildew. At the seedling stage, six biological replicates were collected from the leaves of diseased plants in the disease nursery and non-diseased plants in the normal field, respectively (S33G in the disease nursery and R33G in the normal field). The alterations in metabolites and metabolic pathways in susceptible and normal plants were studied by using LC/MS technology. The results demonstrate that in the S33G-R33G comparison group, 679 differentially expressed metabolites are screened, with 294 up-regulated metabolites and 385 down-regulated metabolites, and the differential metabolites are enriched to 58 metabolic pathways. Alkaloids, fatty acids, flavonoids, terpenoids, and polyketones are the most up-regulated differential metabolites, while lipids and lipid molecules, organic oxygen compounds, organic acids and derivatives, and other compounds are the most down-regulated differential metabolites. By comparison, it is discovered that arachidonic acid metabolism, diterpene biosynthesis, purine metabolism, oxidative phosphorylation, α-linolenic acid metabolism, citrate cycle (TCA cycle), nicotinate and nicotinamide metabolic pathways are considerably activated.
... Salicylic acid (SA) is a phytohormone that regulates multiple aspects of plant life, including disease resistance, leaf senescence, flowering, and thermogenesis (Vlot et al., 2009;Raskin, 1992). In particular, the roles of SA in plant defense and senescence have been thoroughly investigated, and both processes share some components in SA signaling and regulation (Love et al., 2008;Rivas-San Vicente et al., 2011;Zhang et al., 2017). ...
In plants, salicylic acid (SA) hydroxylation regulates SA homoeostasis, playing an essential role during plant development and response to pathogens. This reaction is catalyzed by SA hydroxylase enzymes, which hydroxylate SA producing 2,3- dihydroxybenzoic acid (2,3-DHBA) and/or 2,5-dihydroxybenzoic acid (2,5-DHBA). Several SA hydroxylases have been recently identified and characterized from different plant species; however, no such activity has been previously reported in maize. In this work, we describe the identification and characterization of a new SA hydroxylase in maize plants. This enzyme, with high sequence similarity to previously described SA hydroxylases from Arabidopsis and rice, converts SA into 2,5-DHBA; however, it shows different kinetics properties to those from previously characterized enzymes, and it also catalyzes the conversion of the flavonoid dihydroquercetin into quercetin in in vitro activity assays, suggesting that the maize enzyme may have different roles in vivo as those previously reported from other species. Despite this, ZmS5H-1 can complement the resistance to pathogen and early senescence phenotypes of Arabidopsis s3h mutant plants. Finally, we characterized a maize mutant in the S5H-1 gene ( s5h-1 ) that has altered growth, senescence and increased resistance against Colletotrichum graminicola infection, showing not only changes in SA and 2,5-DHBA but also variations in flavonol levels. Together, the results presented here provide evidence that SA hydroxylases in different plant species have evolved to show differences in catalytic properties that may be important to fine tune SA levels and other phenolic compounds such as flavonols to regulate different aspects of plant development and defense against pathogens.
... About 0.02 g ascorbic acid was added to the sonicated solution to prevent oxidation of Fe NPs and loss of activity. Regarding the free state, SA is a crystalline powder with pH 2.4 and a melting point of 157-159°C [15], so SA cannot be conjugated with Fe NPs during preparation. ...
Aims
This study aimed to examine the effect of magnetite coating of salicylic acid and Cu metal nanoparticles on yield, cellular contents, and some biochemical constituents of wheat subjected to heat stress.
Background
An applied experiment was conducted over two seasons at the Agricultural Experimental Station of Desert Research Center (DRC), which was supervised by the El Wadi El Gadeed Governorate in Egypt. The grains of wheat cultivars Sids1 (tolerant) and Gimmeza7 (sensitive) were treated with copper metal as NPs (Cu NPs) (0.25, 0.50, 0.75, 1.0, and 10ppm) and magnetite NPs (0.25, 0.50, 0.75, 1.0 and 10ppm) coated with salicylic acid at 100ppm (Fe NPs+SA).
Objective
The objective of this study was to examine wheat tolerance to heat stress and subsequently yield by comparing two wheat cultivars under the same conditions.
Method
The chemically formulated nanoparticles were well characterized and applied in two wheat cultivars subjected to heat stress.
Results
The results showed that all NPs treatments had a positive impact on all physiological parameters and grain yield. Sids1 surpassed Gemmeiza7 in the quality of wheat grains (essential, non-essential amino acids). However, Gimmeza7 exceeded Sids1 in yield quantity, especially with the application of SA+Fe NPs at 0.50 ppm. These effects were associated with heat tolerance and the best survival in wheat cultivars. There was an increase in glutathione content, antioxidant enzymes (Glutathione -S- Transferase), and/or a decline in malondialdehyde content.
Conclusion
Conclusion: Fe NPs+SA (0.5ppm) helped the Gimmeza7 cultivar to mitigate the effects of heat stress through activating growth, glutathione, and glutathione S transferase, enhancing yield quantity in two wheat cultivars (Misr1 and Gimmeza11), and decreasing their MDA content.
... It's been discovered to be an endogenous regulatory signal that helps plants defend themselves against infections. It's also a natural signal molecule for defense system activation (Anosheh et al. 2012;Ashraf et al. 2010;Raskin 1992). Plant stress tolerance has been demonstrated to improve when SA is used. ...
... It's been discovered to be an endogenous regulatory signal that helps plants defend themselves against infections. It's also a natural signal molecule for defense system activation (Anosheh et al. 2012;Ashraf et al. 2010;Raskin 1992). Plant stress tolerance has been demonstrated to improve when SA is used. ...
The miracle tree, Moringa oleifera, offers a wide range of applications in crop science, ranging from improved stand establishment and growth promotion to resistance to biotic and abiotic challenges. Moringa leaf and seed extracts can thus be utilized for seed treatment and foliar application. Moringa cultivation should consequently be encouraged and new uses and applications explored. In addition, a substantial amount of studies regarding understanding many parts of the Moringa genome in respect to biotic stressors must be explored. In addition, studies on the association between phenotypic and molecular data and genetic maps (both related and physical maps) are needed to identify genes in reproductive competition. Next-generation sequencing (NGS) has the potential to become an accessible tool for discovering genome- wide genetic markers and generating saturated gene maps at a reasonable cost and time. Moringa oleifera under Stressful Conditions.
... It occurs naturally in plants in small amounts. It participates in the stomata regulation system, responding rapidly to environment changes, nutrient uptake, biological and enzymatic activity, and exogenously sprayed SA interact with stress signaling mechanisms [12,13]. Catalase and ascorbate peroxidase are the main enzymes involved in the removal of H 2 O 2 in plants, and SA can; inhibit their activities; this inhibition leads to a local increase in H 2 O 2 levels, which enhances adaptive responses in plants, such as the growth response to various stimuli such phenylalanine ammonia-lyase (PAL), is the first enzyme and committed in the phenolic metabolic pathway [9,13,14]. ...
Sweet peppers are consumed worldwide, and traditional uses have sparked interest in their applications as dietary antioxidants, which can be enhanced in plants using elicitors. These are endowed with phytochemicals with potential health benefits such as antioxidants, bioavailability, and bioaccessibility. The trend in metabolomics shows us chemical fingerprints linking metabolomics, innovative analytical form, and bioinformatics tools. The objective was to evaluate the impact of multiple stress interactions, elicitor concentrations, and electrical conductivity on the concentration of secondary metabolites to relate their response to metabolic pathways through the foliar application of a cocktail of said elicitors in pepper crops under greenhouse conditions. The extracts were analyzed by spectrophotometry and gas chromatography, and it was shown that the PCA analysis identified phenolic compounds and low molecular weight metabolites, confirming this as a metabolomic fingerprint in the hierarchical analysis. These compounds were also integrated by simultaneous gene and metabolite simulants to obtain effect information on different metabolic pathways. Showing changes in metabolite levels at T6 (36 mM H 2 O 2 and 3.6 dS/m) and T7 (0.1 mM SA and 3.6 dS/m) but showing statistically significant changes at T5 (3.6 dS/m) and T8 (0.1 mM SA, 36 mM H 2 O 2 , and 3.6 dS/m) compared to T1 (32 dS/m) or control. Six pathways changed significantly (p < 0.05) in stress-induced treatments: aminoacyl t-RNA and valine-leucine-isoleucine biosynthesis, and alanine-aspartate-glutamate metabolism, glycoxylate-dicarboxylate cycle, arginine-proline, and citrate. This research provided a complete profile for the characterization of metabolomic fingerprint of bell pepper under multiple stress conditions.
... This study aimed to characterise the efficacy and defence response mechanisms of applying SA in combination with an antagonistic bacterium SF14 to control green mould caused by P. digitatum in postharvest. SA is a natural phenolic compound and plant defence hormone that promotes plant immunity when plants are challenged with pathogens Raskin, 1992). In this study, the use of SA alone at different concentrations was proven effective in controlling green mould disease. ...
Title "Induced Systemic Response in Plants against Biotic Stress"
Edited by Chetan Keswani, Raffaella Balestrini, Tatiana Minkina, Satyendra Singh, Ugo De Corato, Estibaliz Sansinenea
Description
Microbial biopesticides reduce disease incidence by triggering host response. This phenomenon is known as Induced Systemic Resistance (ISR). During this elevated state of resistance, several defense pathways are co-activated in the host system. The proposed special issue will focus on the role of phenylpropanoid derivatives in plant defense and plant–microbe (++) interactions for overcoming biotic stress. In addition, the SI will also explore the metabolic regulation of phenylpropanoid pathway at the molecular level, and in response to phytohormones under biotic stress.
... Salicylic acid (SA) is a phenolic compound extracted from willow bark for the first time (Raskin et al., 1990). Since the 1960s, SA has been found to be used as a plant hormone (Raskin, 1992), mainly used in plant stress resistance, promoting plant growth and improving plant disease resistance (Van Butselaar & Van Den Ackerveken, 2020). In recent years, with the understanding of medicinal components, SA has been applied to the study of inducing secondary metabolism. ...
Sanghuangporus baumii is a medicinal fungi with anti-inflammatory, liver protection and antitumour effects. Terpenoids are one of the main medicinal ingredients of S. baumii. However, terpenoid production by wild-type S. baumii cannot meet the market demand, which affects its application in medical care. Therefore, exploring how to increase terpenoid content in S. baumii is a promising path in this research field. Salicylic acid (SA) is a secondary metabolite. In this study, a concentration of 350 μmol/L SA was added into fungal cultivations for 2 and 4 days, and then the transcriptome and metabolome of untreated mycelia and treated with SA were analysed. The expression of some genes in the terpenoids biosynthesis pathway increased in SA-induced cultivations, and the content of isopentenyl pyrophosphate (IPP) and geranylgeranyl-PP (GGPP) increased significantly as well as the contents of triterpenoids, diterpenoids, sesquiterpenoids and carotenoids. The gene FPS was considered to be a key gene regulating terpenoid biosynthesis. Therefore, FPS was overexpressed in S. baumii by Agrobacterium tumefaciens-mediated genetic transformation. The gene FPS and its downstream gene (LS) expression levels were confirmed to be increased in the FPS overexpressing transformant, and terpenoid content was 36.98% higher than that of the wild-type strain in the evaluated cultivation conditions.
... This inequality can be observed within members of the same family (Rivas-San Vicente and Plasencia 2011). SA is considered a potent plant hormone of phenolic nature (Raskin 1992) due to its essential role in plant growth and development (Popova et al. 1997). Previous studies have shown that endogenous SA content increases rapidly subjected to various stresses (Kunkel and Brooks 2002;Janda et al. 2014;Kahn et al. 2015). ...
Herbicides are used in agriculture to increase crop yield. However, their use often prompts concern about the consequences safety of crop production. Salicylic acid (SA) is a phenolic compound considered a phytohormone that confers plant resistance to different stresses. To determine the influence of SA on the reduction of herbicide-induced toxicity, we used young bean (Phaseolus vulgaris L.) seedlings treated with 1 mM of SA, 100 µM of prometryne or combined treatments. After 30 days of culture, prometryne treatment resulted in plant growth inhibition (shoot height, leaf area, fresh and dry weight) and decreased photosynthetic pigments content. It increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels. Meanwhile, the activities of enzymatic antioxidants, catalase (CAT) and ascorbate peroxidase (APX), as well as herbicide detoxification enzyme glutathione S‑transferase (GST), were significantly improved. Furthermore, herbicide enhanced proline amount and decreased that of glutathione. These findings reflect the presence of stress status. An exogenous supply of SA seemed to reduce the deleterious effects caused by prometryne and appeared to overcome this stress status. Such positive effect was reflected by enhancement of growth and leaf pigments contents, regulating antioxidant enzyme activities (CAT, APX, GST), and decreasing oxidative stress indices. This study demonstrates that exogenous application of SA to young bean plants reversed and/or minimized the damage caused by prometryne through the protection and improvement of some morpho-biochemical characters.
... SA is a naturally occurring phenolic compound in plants, also known as 2-hydroxybenzoic acid, and is one of the major plant hormones that plays a crucial role in plant metabolism [8][9][10][11]. It has an important influence on physiological processes in plants, such as growth, plant development and their adaptations to stress factors [10] as well as on the expression of inducible traits in the activation of plant defenses when attacked by pests [12]. Methyl salicylic acid (MeSA), a volatile derivative and an inactive precursor of SA, plays a key role in long-distance signaling from infected to uninfected tissue through the phloem [13,14]. ...
The effects of salicylic acid (SA) and one of its better-known derivatives—methyl salicylic acid (MeSA)—on the infection of apple fruits with the fungus Monilinia laxa, which causes brown rot, were investigated. Since research to date has focused on preventive effects, we also focused on the curative use of SA and MeSA. Curative use of SA and MeSA slowed the progression of the infection. In contrast, preventive use was generally unsuccessful. HPLC–MS was used to analyze the content of phenolic compounds in apple peels in healthy and boundary peel tissues around lesions. The boundary tissue around the lesions of untreated infected apple peel had up to 2.2-times higher content of total analyzed phenolics (TAPs) than that in the control. Flavanols, hydroxycinnamic acids and dihydrochalcones were also higher in the boundary tissue. During the curative treatment with salicylates, the ratio of TAP content between healthy and boundary tissue was lower (SA up to 1.2-times higher and MeSA up to 1.3-times higher content of TAPs in boundary compared to those in healthy tissue) at the expense of also increasing the content in healthy tissues. The results confirm that salicylates and infection with the fungus M. laxa cause an increased content of phenolic compounds. Curative use of salicylates has a greater potential than preventive use in infection control.
... These results suggested that SL affected substance transformation by promoting the increase of ACC. SA is a phenolic compound, which is involved in regulating plant growth and development (Raskin, 1992). Yu et al. (2021) mentioned that SA and ethylene synergistically promoted leaf senescence in Arabidopsis. ...
Camellia oleifera Abel. (C. oleifera), one of the four woody oil-producing plants in the world produces edible oils with high percentage of unsaturated fatty acid content in seeds. The mature C. oleifera seeds continue to undergo a series of physiological changes after harvest. To this end, the dynamic changes in nutrients, oil content, fatty acid composition, and endogenous hormone content in C. oleifera seeds under different natural drying times after harvest were investigated. The content of soluble sugar and soluble protein of C. oleifera seeds increased with the extension of natural drying, especially soluble sugar content increased nearly 2-fold at 30 d after post-harvest natural drying compared with that of the control group. The content of oil reached a peak (23.6%) at 30 d after post-harvest natural drying. During the post-harvest natural drying process, the relative content of palmitic acid and oleic acid increased, while the relative content of palmitic acid and linoleic acid decreased. Furthermore, the levels of unsaturated fatty acids (oleic acid, linoleic acid, linolenic acid, and arachidonic acid) increased significantly with increasing natural drying time. The overall trend of endogenous hormones SA, SL, and ACC concentrations increased with the post-harvest natural drying process. Furthermore, the concentration of SA, SL, and ACC were positively correlated with oil content. Altogether, post-harvest natural drying for 30 days significantly promoted the anabolism of oil and improved the quality of C. oleifera seeds. These findings provide a scientific basis for reasonable post-harvest treatment to improve Camellia oil yield.
... Salicylic acid is involved in several defence function as well as normal development processes such as plant thermo genesis, flower development and allelopathy (Raskin, 1992 activators, salicylic acid, a-amino butyric acid, isonicotinic acid and azoxystrobin were evaluated in vitro and in vivo. Salicylic acid at 100 ppm was proved most effective in inhibiting mycelial growth. ...
... The effect of drought stress can be reduced and the crop performance can be improved by using the seed priming techniques [16,17]. Salicylic acid (SA) is a seven-carbon phenolic compound produced by the plants which can regulate the growth [18]. Salicylic acid increased resistance to water stress in wheat seedling [19]. ...
... K. Singh et al., 2001). It also stimulates cell division and cell enlargement, increases the tolerance of plants to all kinds of stresses, and protects plant cells from oxidation by free radicals, which can explain the above results (Hayat et al., 2007;Lee et al., 1995;Raskin, 1992) ...
The present investigation was aimed at assessing the efficacy of N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU) and salicylic acid on fruit retention, yield, and quality of mango cv. Dusehri. The research was carried out at the Department of Fruit Science, Punjab Agricultural University, Ludhiana, India. The experiment was conducted simultaneously at two different locations for two cropping seasons during 2019–20 and 2020–21. Fruit retention enhancing treatments of 2,4-Dichlorophenoxyacetic acid (2,4-D) (@20 ppm), CPPU (@5, 10, and 15 ppm), and salicylic acid (@100, 200, and 300 ppm) were applied at pea stage of fruit growth. Experimental plants were observed for various reproductive, yield, and fruit quality parameters. The results indicated that foliar application of CPPU (T6-CPPU @10 ppm) significantly enhanced fruit retention during marble and harvest stages at both locations in both seasons. The novel growth hormone also improved fruit yield, fruit weight, and fruit quality in mango cv. Dusehri. Foliar applied salicylic acid recorded intermediate values for observed parameters. Therefore, foliar application of CPPU can be considered as a better alternative to 2,4-D for fruit drop management of mango.
... SA, a small phenolic compound that is transported via the phloem, serves a variety of functions: enhancing disease, drought, and heat resistance (Raskin, 1992). According to Li et al. (2015a), SA pretreatment increases LCD activity, helps endogenous H 2 S build up, and further enhances the heat tolerance response of maize seedlings. ...
Adverse environmental constraints such as drought, heat, cold, salinity, and heavy metal toxicity are the primary concerns of the agricultural industry across the globe, as these stresses negatively affect yield and quality of crop production and therefore can be a major threat to world food security. Recently, it has been demonstrated that hydrogen sulfide (H2S), which is well-known as a gasotransmitter in animals, also plays a potent role in various growth and developmental processes in plants. H2S, as a potent signaling molecule, is involved in several plant processes such as in the regulation of stomatal pore movements, seed germination, photosynthesis and plant adaptation to environmental stress through gene regulation, post-translation modification of proteins and redox homeostasis. Moreover, a number of experimental studies have revealed that H2S could improve the adaptation capabilities of plants against diverse environmental constraints by mitigating the toxic and damaging effects triggered by stressful environments. An attempt has been made to uncover recent development in the biosynthetic and metabolic pathways of H2S and various physiological functions modulated in plants, H2S donors, their functional mechanism, and application in plants. Specifically, our focus has been on how H2S is involved in combating the destructive effects of abiotic stresses and its role in persulfidation. Furthermore, we have comprehensively elucidated the crosstalk of H2S with plant growth regulators.
... Salisilik asidin diğer birçok fenolik bileşik gibi, bitki büyümesinin düzenlenmesi, gelişimi ve diğer organizmalarla etkileşiminde temel rol oynadığı görüşü ortaya çıkmıştır (Harborne, 1980). Araştırmalarda salisilik asidin birçok fizyolojik ve biyokimyasal etkilerinden söz edilmiş (Raskin, 1992) ve SA, sıcaklık stresi de dâhil olmak üzere, abiyotik streslere karşı bitki tepkilerindeki rolünden dolayı büyük ilgi görmüştür. Dünyada ekonomik anlamda üzüm üretimi ılıman iklime sahip bölgelerde gerçekleştirilmektedir. ...
Bitkiler bulundukları çevre içinde, gelişimlerini sınırlayan, farklı şekillerde meydana gelebilen olumsuz koşullara maruz kalabilmektedirler. Bitkilerde büyüme, gelişme ve metabolizmayı etkileyen ve/veya engelleyen bu olumsuz koşullara stres adı verilmektedir. Salisilik asit (SA) bitkilerde yaygın olarak bulunan ve artık günümüzde bitki büyüme ve gelişmesinin düzenlenmesinde önemli rol oynadığı kabul edilen bir fitohormondur. SA aynı zamanda, tuzluluk, yüksek ve düşük sıcaklık, su, ağır metal, don ve kuraklık stresi gibi abiyotik stres şartlarında bitkilerin toleransını artırmaktadır. Çalışmamız da Türkiye‘nin önemli beyaz şaraplık üzüm çeşitlerinden olan ve Tokat‘ta yaygın yetiştiriciliği yapılan Narince üzüm çeşidine ait fidanlar kullanılmıştır. Uygulanan yüksek sıcaklık stresi öncesi bitkilere 4 farklı dozda ( 0, 0.5, 1.0, 1.5 µmol l-1 ) salisilik asit (SA) uygulanmış olup bitki büyütme kabininde 40ËšC‘de 12 saat boyunca yüksek sıcaklığa maruz bırakılmıştır. Stres uygulamasından 21 gün sonra ise bitkilerden bitki büyümesini takip etmek amacıyla, sürgün uzunluğu (cm), yaş- kuru sürgün ve kök ağırlıkları (g) alınmış, Salisilik asidin etkisini ortaya koymak amacıyla ise oransal su kapsamı (%), iyon akışı (%) ve hücre zarı zararlanma oranı (%) hesaplanmıştır.
... This study aimed to characterise the efficacy and defence response mechanisms of applying SA in combination with an antagonistic bacterium SF14 to control green mould caused by P. digitatum in postharvest. SA is a natural phenolic compound and plant defence hormone that promotes plant immunity when plants are challenged with pathogens Raskin, 1992). In this study, the use of SA alone at different concentrations was proven effective in controlling green mould disease. ...
Penicillium digitatum is a major post-harvest pathogen of citrus fruit causing tremendous economic losses. In this study, salicylic acid (SA) and antagonistic bacteria Bacillus amyloliquefaciens (SF14) were tested in controlling P. digitatum (green mould) infections as an alternative to chemical controls. Three concentrations of SA (0.5, 1, and 2%) were tested for their antifungal activity in both in vitro and in vivo conditions alone and in combination with SF14. Fruit quality parameters including fruit firmness, weight loss, titratable acidity, and soluble solids content were evaluated. The impact of these biological treatments was also investigated by measuring the changes in organic and mineral properties of orange fruits using Fourier transform infrared spectroscopy (FT-IR). Enzymatic activity including phenylalanine ammonia-lyase (PAL), total polyphenols and flavonoids was also tested. In vitro assays showed that SF14 combined with 0.5% SA provided the highest inhibition of green mould growth reaching 72.98%. Inhibition of spore germination was also highest in the same treatment od reaching 63.40%. FTIR of fungal biomass confirmed an alteration of fungal well wall following biological treatments. Moreover, during in vivo assays, the combination of SF14 and 0.5% SA produced the lowest disease severity (5.43%) without considerably affecting the fruit quality. Further investigation of the effect of these treatments on the mineral composition of treated oranges showed that Ca, Fe, K, Mg, and Na concentrations were significantly affected. Changes in these elements may show a defence reaction induced by the biological treatments against the pathogen, which was also confirmed with the measurement of PAL activity, total polyphenols, and flavonoids. Interestingly, FTIR of citrus peel indicated significant changes in the content of bands denoting for phenolic and aromatic rings, suggesting an induced resistance against the pathogenic fungus. Overall, our findings suggested that the combination of both bacterial antagonist SF14 and 0.5 % SA can control the green mould of citrus, and as such constitutes a safer alternative to chemicals during postharvest storage.
The leaves of Stevia rebaudiana Bertoni contain steviol glycosides (SGs), which provide the sweet taste of stevia. However, drought can have a negative impact on the plant's growth and development. To address this issue, signaling molecules such as sodium nitroprusside (SNP), spermidine (SPD), and salicylic acid (SA) are often applied to increase plant tolerance. However, the combined effects of these molecules have not been extensively studied. This research aimed to investigate the effects of controlled elicitation with SA, SNP, SPD, and their combinations on plant performance, SG content, and drought stress mitigation in Stevia rebaudiana under drought stress. The elicitor treatments were found to result in a significant increase in SG content, with 0.1 mM SA being the most effective treatment. Additionally, the treatments were able to reduce the stress effects on growth parameters to non-stress levels. The use of SPD, SA+SNP, and SPD+SNP on stressed plants significantly increased CAT and SOD activity, resulting in a more active antioxidant defense system that lowered MDA contents and H2O2 generation. These findings suggest that stevia cultivation with controlled elicitation could be used to improve plant growth, tolerance, and SG production under drought stress conditions.
Pear anthracnose caused by Colletotrichum fructicola is one of the main fungal diseases in all pear-producing areas. The degradation of ubiquitinated proteins by the 26S proteasome is a regulatory mechanism of eukaryotes. E3 ubiquitin ligase is substrate specific and is one of the most diversified and abundant enzymes in the regulation mechanism of plant ubiquitination. Although numerous studies in other plants have shown that the degradation of ubiquitinated proteins by the 26S proteasome is closely related to plant immunity, there are limited studies on them in pear trees. Here, we found that an E3 ubiquitin ligase, PbATL18, interacts with and ubiquitinates the transcription factor PbbZIP4, and this process is enhanced by C. fructicola infection. PbATL18 overexpression in pear callus enhanced resistance to C. fructicola infection, whereas PbbZIP4 overexpression increased sensitivity to C. fructicola infection. Silencing PbATL18 and PbbZIP4 in Pyrus betulaefolia seedlings resulted in opposite effects, with PbbZIP4 silencing enhancing resistance to C. fructicola infection and PbATL18 silencing increasing sensitivity to C. fructicola infection. Using yeast one-hybrid screens, an electrophoretic mobility shift assay, and dual-luciferase assays, we demonstrated that the transcription factor PbbZIP4 upregulated the expression of PbNPR3 by directly binding to its promoter. PbNPR3 is one of the key genes in the salicylic acid (SA) signal transduction pathway that can inhibit SA signal transduction. Here, we proposed a PbATL18-PbbZIP4-PbNPR3-SA model for plant response to C. fructicola infection. PbbZIP4 was ubiquitinated by PbATL18 and degraded by the 26S proteasome, which decreased the expression of PbNPR3 and promoted SA signal transduction, thereby enhancing plant C. fructicola resistance. Our study provides new insights into the molecular mechanism of pear response to C. fructicola infection, which can serve as a theoretical basis for breeding superior disease-resistant pear varieties.
Equilibrium mole fraction solubility of salicylic acid in nine aqueous-ethanolic mixtures, as well as in neat water and neat ethanol, was determined at seven temperatures from T = (293.15 to 323.15) K. Salicylic acid solubility in these mixtures was adequately correlated with well-known correlation/prediction methods based on Jouyban-Acree model. Apparent thermodynamic quantities, i.e. Gibbs energy, enthalpy, and entropy, for the dissolution and mixing processes, were computed by means of the van’t Hoff and Gibbs equations. The enthalpy–entropy compensation plot of enthalpy vs. Gibbs energy of dissolution was not linear exhibiting positive slopes from neat water to the mixture of w1 = 0.30 and from the mixture of w1 = 0.50 to neat ethanol indicating enthalpy-driven drug transfer processes but negative in the interval of 0.30 < w1 < 0.50 indicating entropy-driven drug transfer processes from more polar to less polar solvent systems. Moreover, by using the inverse Kirkwood–Buff integrals it is observed that salicylic acid is preferentially solvated by water molecules in water-rich mixtures but preferentially solvated by ethanol molecules in those mixtures of 0.24 < x1 < 1.00.
Increasing global warming is severely affecting tree growth and development. However, research on the sex-specific responses of dioecious trees to warming is scarce. Here, male and female Salix paraplesia were selected for artificial warming (an increase of 4 °C relative to ambient temperature) to investigate the effects on morphological, physiological, biochemical and molecular responses. The results showed that warming significantly promoted the growth of female and male S. paraplesia, but females grew faster than males. Warming affected photosynthesis, chloroplast structures, peroxidase activity, proline, flavonoids, nonstructural carbohydrates (NSCs) and phenolic contents in both sexes. Interestingly, warming increased flavonoid accumulation in female roots and male leaves but inhibited it in female leaves and male roots. The transcriptome and proteome results indicated that differentially expressed genes and proteins were significantly enriched in sucrose and starch metabolism and flavonoid biosynthesis pathways. The integrative analysis of transcriptomic, proteomic, biochemical and physiological data revealed that warming changed the expression of SpAMY, SpBGL, SpEGLC and SpAGPase genes, resulting in the reduction of NSCs and starch and the activation of sugar signaling, particularly SpSnRK1s, in female roots and male leaves. These sugar signals subsequently altered the expression of SpHCTs, SpLAR and SpDFR in the flavonoid biosynthetic pathway, ultimately leading to the differential accumulation of flavonoids in female and male S. paraplesia. Therefore, warming causes sexually differential responses of S. paraplesia, with females performing better than males.
Hydrogen sulfide (H2S), merely considered a harmful gas, stays as an intrinsic new gaseous signaling agent that has been broadly researched in plants from seed development to senescence. As global regulatory authorities, phytohormones, which include stimulators (such as auxin: AUX; gibberellin: GA; cytokinin: CTK; and melatonin: MEL) and inhibitors (such as ethylene: ETH; abscisic acid: ABA; salicylic acid: SA; and jasmonic acid: JA), hold an indispensable concern during the progressive stages, advancement, reaction, and adjustment to hostile conditions of plants. Phytohormones are now thought to intend the most important pursuits for increasing plant growth, throughput, and strain resistance, that influence agricultural plant performance and productivity. Exogenous H2S reduces Ethylene generation in peach seedling roots amid waterlogged conditions, and their interplay adversely impacts Ethylene manufacture during stress caused by osmosis. Ethylene-induced closure of stomata also needs H2S. The interplay of H2S and ethylene is critical for reducing hexavalent chromium stress. H2S collaborates with phytohormones, additional gasotransmitters, and ionic messages like abscisic acid (ABA), ethylene, auxin, CO, and NO in its regulatory roles.KeywordsPhytohormonesHydrogen sulfide (H2S)EthyleneStress toleranceWaterloggingGasotransmittersSignal crosstalk
Bread Wheat is one of the most important crops which has main position in nutrition of the world's population. Powdery mildew, caused by the biotrophic pathogen Blumeria graminis f.sp tritici (Bgt), known as a destructive disease of wheat worldwide. There are several methods to control the disease, but use of
inducers able to induce a systemic resistance in plants are very important. As of Piriformospora indica endomycorrhiza fungi and salicylic acid after symbioted with roots and inoculated on plants, respectively, with inducting systemic resistance can play a pivotal role in inducting resistance of plant to pathogens. Plants in response to biological agents produce numerous compounds such as reactive oxygen species,
phytoalexins and a group of proteins called pathogenesis related (PR) proteins. In order to examinate the
expression rate of PR1, PR2, PR3, PR5, PRX, PAL, NPR1, MLO and BI-1 genes using Real Time PCR
technique in response to Bgt and also change pattern of peroxidase, catalase and ascorbate peroxidase
enzymes, 40 Iranian commercial wheat genotypes were screened using Bgt in seedling stage. On the basis of
colonies number formed on samples, cv. Flat was selected as susceptible lines, and cv. Tajan and cv.
Gascojen were selecteted as as spring and winter resistance genotypes, respectively. For testing the ability of
fungus P. indica and SA for inducing resistance in wheat against Bgt fungus, cv. Falat treated seperately and
then exposed to Bgt fungi together with control plants. Similarly, to compare the pattern of genes
expression, cv. Falat together with resistant cultivars were exposed to fungus Bgt. The expression rate of
target genes was carried out at 5 time courses and in 3 independent replicates and then genes expression rate
were normalized in comparing with their relative internal reference Actin gene. Results indicated that in both
groups of treated and control plants, levels were increased after infection for all genes excepts MLO and BI-
1. Maximum expression level of genes were observed at 24 hours after infection. This process was observed
slowly in control plants but caused early and faster induction of plant defense genes in treated plants at early
hours after infection. At 48 hours after inoculatin, transcript levels of induced genes started to dampen in
both groups of experimental plants, indicating effective suppression of defense-associated genes upon
haustorium development. Also, comparing the expression patterns of genes in susceptible and resistant
cultivars showed that the expression of these genes in induced resistant varieties were much faster than the
Falat susceptible cultivar. In addition, the results of this study showed that the antioxidant activities of the
treated plants and resistant varieties are less than of the susceptible cultivar. Therefore, this phenomenon can
promoted the idea that these plants with reduced enzyme activities inducting the rapid cell death that is
combated with the pathogen. While symbiant plants except overexpression of peroxidase enzyme, were not
showed significantly different for other enzyme activitiesy than control plants. Therefore, the symbiotic
fungi seems can not be effective for inducing resistance via enzymatic pathway. Overall, results indicated
that Tajan and Gascojen cultivars with overexpression of resistance genes and antioxidant enzymes have
high potential for improving resistance to powdery mildew. Both of P. indica and SA inducers are able to
induce resistance in susceptible cultivar through overexpression of resistance genes and reducing number of
colonies grown on Bgt fungus p
Severe outbreaks of diseases are the consequences of interactions between pathogenic microorganisms and cultivated crops. Plants are recurrently exposed to various biotic stresses in their innate environment. To endure such unfavorable circumstances, they have acquired complex mechanisms to react and acclimatize to biotic stresses. Plants are host to many contagious diseases caused by both living and nonliving agencies like viruses, bacteria, fungi, nematodes, and stress conditions. Comparatively small proportions of pathogens effectively assault the host plant which results in diseases. Plant disease is a physiological disorder or structural irregularity that is destructive to the plant and its products that suppress its monetary value. Plants are sessile and responsive organisms that encounter a variety of environmental strains. Throughout their life cycle, plants respond to diverse intimidations arising from their external environment. Fungal pathogens have a meticulous impact causing a major damage and yield losses in agriculture. Due to their sessile nature plants develops a broad range of strategies that cooperatively work in defense against biotic and abiotic stresses. Plant diseases can be viewed as obstinate roadblocks to the rapid advancement in agricultural yield. Interpreting the molecular basis of plant–pathogen interaction facilitates us to select plant resistance genes. The present work is focused on the consequence of fungus Macrophomina phaseolina on the growth of chickpea plants via monitoring various biochemical parameters which play important role in defense response upon infection with the pathogen. Comparative studies on the effect of M. phaseolina toxin in chickpea as well as other host plants like Brassica oleracea, Brassica juncea, Helianthus annus, and Vigna mungo via detached leaf bioassay method are also planned.KeywordsChickpeaChitinase geneResistant
Esta obra constituiu-se a partir de um processo colaborativo entre professores, estudantes e pesquisadores que se destacaram e qualificaram as discussões neste espaço formativo. Resulta, também, de movimentos interinstitucionais e de ações de incentivo à pesquisa que congregam pesquisadores das mais diversas áreas do conhecimento e de diferentes Instituições de Educação Superior públicas e privadas de abrangência nacional e internacional. Tem como objetivo integrar ações interinstitucionais nacionais e internacionais com redes de pesquisa que tenham a finalidade de fomentar a formação continuada dos profissionais da educação, por meio da produção e socialização de conhecimentos das diversas áreas do Saberes. Agradecemos aos autores pelo empenho, disponibilidade e dedicação para o desenvolvimento e conclusão dessa obra. Esperamos também que esta obra sirva de instrumento didático-pedagógico para estudantes, professores dos diversos níveis de ensino em seus trabalhos e demais interessados pela temática.
The experiment was conducted in the nursery of Diyala Agriculture Directorate during the growing seasons 2021 from March to November 2021 to study the effect of growth promoters Humic acid, Atonic and Salicylic growth promoters acid spray on some chemical and vegetative parameters of Local and bloody orange transplants budded on sour orange rootstock. The experiment included two factors, the first one was two orange cultivars (Local and bloody), and the second was the spray of growth promoters(Humic acid, Atonic and Salicylic acid). Humic acid was sprayed at 1%, Atonic at 1 ml L ⁻¹ , and salicylic acid at 300 mg L ⁻¹ . Results revealed the superiority of bloody cultivar compared to local orange in most studied characteristics (plant height, scion diameter, leaf area, leaves chlorophyll, nitrogen, phosphorous and potassium content). The interaction between salicylic and atonic showed a significant increase in scion diameter, leaf area, leaf chlorophyll content, nitrogen, phosphorous and potassium content compared to untreated transplants.
Chitosan (CS), a bio-renewable natural material, has the potential to be utilized as a biopolymer for food packaging films (PFs)/coatings. However, its low solubility in dilute acid solutions and poor antioxidant and antimicrobial activities limit its application in PFs/coatings. To address these restrictions, chemical modification of CS has garnered increasing interest, with graft copolymerization being the most extensively used method. Phenolic acids (PAs) as natural small molecules are used as excellent candidates for CS grafting. This work focuses on the progress of CS grafted PA (CS-g-PA) based films, introducing the chemistry and methods of preparing CS-g-PA, particularly the effects of different PAs grafting on the properties of CS films. In addition, this work discusses the application of different CS-g-PA functionalized PFs/coatings for food preservation. It is concluded that the food preservation capability of CS-based films/coatings can be improved by modifying the properties of CS-based films through PA grafting.
Despite the important role of root exudates in the functions and processes of forest ecosystems, few studies have examined the effects of warming on the chemical composition of root exudates. In this study, we examined how warming affected composition of fine root exudates of Chinese fir (Cunninghamia lanceolata) saplings in different seasons. We designed a complete randomized block design soil warming (+ 4 ℃) experiment. Through liquid chromatography-mass spectrometry (LC/MS) in combination with a modified culture-based cuvette system, we compared metabolite composition of root exudates between warmed and control saplings. Warming changed the concentration of more metabolites in the summer than the spring. More primary metabolites (e.g., amino acids and organic acids) and defense-related secondary metabolites (e.g., phenols and terpenoids) significantly increased after warming in summer than in spring. Warming enhanced multiple metabolite pathways related to absorption of nutrients (e.g., alanine, aspartate, and glutamate metabolism for N and citrate cycle for P) and water (e.g., arginine biosynthesis) and plant defense (e.g., enhanced tryptophan metabolism in the spring, flavone, and flavonol biosynthesis in the summer). Warming increased the composition and pathways of metabolites in root exudates of Chinese fir saplings. The alternation was much more pronounced in the dry summer suggesting that changes in metabolite composition and pathways are important responses of Chinese fir saplings to drought. These findings provide insights into how climate change may affect important belowground processes in subtropical forests.
The world population is supported by food availability that depends on cultivation. Agriculture, however, comports environmental threats related with global warming and nature contamination. Therefore, more friendly techniques that are less damaging for the environment without resignation of yield have gained attention. Among them, bioinoculants containing microbial species (bacteria and fungi) emerge in the farming market as possible contributors. This review revises the scientific basis of such products as biofertilizers, biostimulators, stress regulators, biopesticides, and bioremediation agents. More than 40 years of research suggests that bioinoculants’ efficiency relies on root growth promotion that enhances soil exploration and root capability for superior nutrient and water uptake, and such growth promotion is mostly dependent (directly and/or indirectly) on production of plant growth regulators (phytohormones) by microorganisms. Notwithstanding, in keeping yield, bioinoculants are not enough by themselves, and they should be combined with other technologies, namely, plants genetically designed for more efficient use of resources, direct sowing, moderate and specifically oriented fertilization, green soil coverage, and crop rotation.KeywordsBioformulationsPGPBPlant growth-promoting bacteriaPlant hormonesRoot efficiencySustainable agriculture
This research was conducted in the experimental field of the General Station of Hort. and Forestry Ministry of Agricalture / Al-Mahaweel, in the two season of 2014 and 2015 to investigate the influance of Salicylic acid (0 ,100 and 200 mg.L-1) , Tryptophan acid (0 ,100 and 200 mg.L-1) and Nutrient solution with King live (0, 1.5 and 3 g.L-1) and their interactions in growth of olive seedlings of Manzanello cultivar. The experiment conducted in arrangement factorial in a completely randomized block design with three replicates (five seedling in each experimental unit), So the number of treatment is 27 distributed randomly on 405 seedling age of 1 year. The data were analyzed by using the ANOVA table using Genstat software and the mean were compared by using the least significant different ( L.S.D.) at 0.05 significant level. Results can be summarized as following :
1. The treatment with Salicylic acid at a concentration of 200mg.L-1 caused a significant increases in all vegetative growth traits ( plant height, stem diameter, branches number, branches lenght, leaves number, leaf area, and vegetative dry weight percentage), and root growth characteristics (roots number, roots length, lateral roots diameter , and roots dry weight percentage ). Salicylic acid on the other hand effected significantly in chlorophyll and percentage of N , P , K ,Fe, Zn , Cu, carbohydrate, C/N ratio, proteins and endogenous plant hormones concentration (IAA, GA3, Cks) in leaves for two seasons of the study were : 90.09& 117.49cm , 9.06& 10.50mm , 11.24&12.63 branches/ seedling , 23.14& 26.51cm , 328.04 & 348.58 leave/ seedling ، 7.06 & 8.17 cm2 , 44.86 &60.22%, 28.87 & 31.86 root/ seedling , 29.83& 35.04 cm , 3.04&4.10mm , 41.96 &54.25 %, 69.15 &77.67 Spad unit , 1.79 & 1.68% , 0.215 & 0.212%, 1.432 &1.428% , 114.19 & 113.37 mg.Kg-1 , 24.03 & 19.78 mg.Kg-1, 15.25&14.77 mg.Kg-1 , 13.80 &13.47%, 7.66 &8.02 , 11.13&10.46 % , 2.147 & 2.042 m molar , 22.614 &21.845 m molar, 11.049 & 10.144 m molar .
2. Tryptophan acid at 200 mg.L-1 increased significantly in all vegetative growth characteristics.
3. Nutrient solution ( King live) at 3 g.L-1 lead to significant increase in most vegetative and root characteristics, also chemical characteristics : percentage of N , P , K ,Fe, Zn , Cu, carbohydrate, proteins, C/N ratio, chlorophyll and endogenous plant hormones concentration (IAA, GA3, Cks) in leaves.
4. Treating olive seedling with Salicylic acid and Tryptophan acid and Nutrient solution reduced significantly the activity of antioxidant enzymes SOD, CAT, and POD, as well as leaf prolene content and concentration of ABA in leaves.
5. The dual interaction of the study factors causes a significant increase in most characteristics under study,while The dual interaction reduced significantly the activity of anti-oxidants enzymes SOD, CAT and POD, as well as leaf proline content and concentration of ABA in leaves.
6. The triple interaction of the trial factors causes a significant increase in in most characteristics under study( plant height, stem diameter, branches number, branches lenght, leaves number, leaf area, and vegetative dry weight percentage), and root growth characteristics (roots lenght, roots number, lateral roots diameter and roots dry weight percentage ) and effected significantly in chlorophyll and percentage of N , P , K ,Fe, Zn , Cu, carbohydrate, C/N ratio, proteins and endogenous plant hormones concentration (IAA, GA3, Cks) in leaves,while The triple interaction significantly reduced the activity of anti-oxidants enzymes SOD, CAT and POD, as well as leaf proline content and concentration of ABA in leaves for two seasons of the study were : 99.15 & 135.26 cm , 12.15 & 13.55 mm , 14.17 & 15.07 branches/ seedling , 27.20 &30.18cm , 379.67& 423.73 leave/ seedling , 9.31 &11.45cm 2, 54.50 &64.32 %, 35.19 &38.15 root/ seedling , 34.81 & 39.42cm , 3.36 &4.48 mm , 49.17 &60.68 %, 88.32 90.83& Spad unit , 1.89& 1.78 % , 0.290 &0.283 %,1.554 1.535& %, 130.94&128.20 mg.Kg-1, 29.74 &22.97 mg.Kg-1, 17.84&17.20 mg.Kg-1 , 15.68 & 15.10 %, 8.47 & 8.86 , 11.66 &11.15% , 0.308 &0.278 micromole.gm-1 dray weight , 2.884 & 2.989m molar , 26.911 & 25.263m molar , 13.642 &13.014 m molar , 116.57 &105.90 m molar , 10.90 &11.28 Un.mol , 1.23 & 2.45 Un.mol , 82.17 &95.64 Un.gm-1 .
Water deficiency is one of the most severe abiotic stresses in rainfed dry lands and limits crop productivity. Exogenous applications of salicylic acid (SA) have been applied to mitigate the adverse effects of water-deficit stresses, but the relative efficacy of different derivatives of SA in enhancing water-deficit tolerance along with the underlying physio-biochemical mechanism and yield of crops is not well documented. Field experiments were conducted to ascertain the relative efficacy of exogenous application of three plant bioregulators (PBRs) [SA, thiosalicylic acid and 5-sulfosalicylic acid (SSA)], each at three concentrations (0.5, 1.0 and 1.5 mM), on the growth, physio-biochemical characteristics and yield of cluster bean under rainfed conditions. Based on a 2-year field experiment, the application of PBRs enhanced yield (from 8 to 16%). The yield enhancement with the application of PBRs was associated with elevated water content (from 9 to 17%), membrane stability (from 12 to 18%) and antioxidant enzyme activity (from 12 to 33%) and reduced lipid peroxidation (from −15 to −34%) in leaves. The effects of PBRs were conditionally type and concentration dependent. The application of SSA at a rate of 1 mM was more effective in enhancing water-deficit tolerance and improving the yield of cluster bean under water shortage conditions. This study provides empirical evidence of the potential for the application of SA and its derivatives to enhance crop yields under drought conditions. The results have direct implications for sustainable crop production for similar regions of the world facing water deficits.
The phytohormone salicylic acid (SA) is known to regulate plant immunity against pathogens. Plants synthesize SA via the isochorismate synthase (ICS) pathway or the phenylalanine ammonia-lyase (PAL) pathway. The ICS pathway has been fully characterized using Arabidopsis thaliana, a model plant that exhibits pathogen-inducible SA accumulation. Many species including Populus (poplar) depend instead on the partially understood PAL pathway for constitutive as well as pathogen-stimulated SA synthesis. Diversity of SA-mediated defense is also evident in SA accumulation, redox regulation, and interplay with other hormones like jasmonic acid. This review highlights the contrast between Arabidopsis and poplar, discusses potential drivers of SA diversity in plant defenses, and offers future research directions.
Treatments of primary leaves of asparagus bean (Vigna sesquipedalis Fruhw.) with salicylate had different effects on resistance to local lesion development caused by tobacco necrosis virus (TNV), depending upon the concentration used for treatment. At 1 mm, salicylate slightly reduced lesion size but not virus accumulation, while at 3 mm it significantly decreased lesion size and virus accumulation. Treatments with 5 mm solutions appreciably increased both parameters, but also damaged the leaf tissue.The hypersensitive reaction of the leaves to virus inoculation was accompanied by the accumulation of five host-coded protein bands (VS0to VS4). However, three (or more) days after treatment with salicylate at any concentration between 1 and 5 mm only one band accumulated and this band appeared to correspond to VS1. This finding clearly questions the role of the VS1 protein in limiting the spread and multiplication of TNV.The leaves responded rapidly to treatment with salicylate with stomatal closure, increased K+ leakage and ethylene production. These responses are generally considered to be general reactions to stress. None of them however, was correlated with any of the observed changes in TNV infection.
Screening for the pathogenesis-related (b) protein patterns of 11Nicotiana species and 30N. tabacum varieties has revealed both inter- and intraspecific variability and 7 different b-proteins (b0, b1, b1, b1, b2, b3 and b4) have been clearly defined. Their genetic determinants are sexually transmitted independently of theN gene conferring resistance to TMV, and a monogenic inheritance has been demonstrated for one of them (b1). Grafting experiments have revealed the existence of a species-aspecific mobile compound responsible for the expression of the b-protein genes, the production of which is probably under the control of theN gene. Among the 5 intraspecific and 6 interspecific hybrids studied, one of them, theN. glutinosa x N. debneyi together with its amphidiploid, synthesizes b-protein (b1) in a constituve way and possesses a high level of resistance to necrosis-inducing viruses. The amphidiploid is able to transfer these two properties to otherNicotianae not only by crossing but also by grafting; it therefore appears to permanently synthesize the mobile compounds. Furthermore, the hypersensitive reaction to TMV in these hybrids is only completely broken down at 35 C, whereas this normally occurs at 30 C in plants with theN gene.
Polyclonal and monoclonal antibodies that recognize the 35-, 36-, and 37-kDa alternative oxidase proteins of Sauromatum guttatum (Schott) were used to isolate a cDNA clone, pAOSG81, from an S. guttatum cDNA expression library. A fusion protein with an apparent molecular mass of 48 kDa was expressed from a pUC119 derivative of pAOSG81 (pAOSG81-119) in Escherichia coli cells and was recognized by the monoclonal antibodies. When the in vitro translated and immunoprecipitated products made from mRNA hybrid-selected by pAOSG81 were analyzed, a single band corresponding to a protein with an apparent molecular mass of 42 kDa was observed. DNA sequence characterization showed that pAOSG81 contains the entire coding region of a protein with a calculated molecular mass of 38.9 kDa, a putative 63-amino acid transit peptide, and a 9-amino acid match to the authentic N-terminal sequence of the 36-kDa alternative oxidase protein. Analyses of the deduced amino acid sequence indicate: (i) that the transit peptide is predicted to form amphiphilic helices, and (ii) that three regions of the processed protein are likely to form transmembrane alpha-helices. We conclude from these data that pAOSG81 represents a nuclear gene, aox1, encoding a precursor protein of one or more of the alternative oxidase proteins of S. guttatum.
Healthy tobacco plants accumulate beta-1,3-glucanases (glucan endo-1,3-beta-glucosidase; EC 3.2.1.39) in their roots and in specific parts of the flowers. After infection with tobacco mosaic virus, acidic and basic beta-1,3-glucanases are induced in the inoculated and virus-free leaves of the plant. An analysis of cDNA clones demonstrated that at least five genes for acidic beta-1,3-glucanases are induced after tobacco mosaic virus infection. Southern blot analysis indicated that the tobacco genome contains approximately eight genes for acidic beta-1,3-glucanases and a smaller number of genes encoding basic beta-1,3-glucanases. Genes from both gene families were cloned and sequenced. The basic isozymes contain a C-terminal extension that is cleaved off during their targeting to the vacuoles. This extension is absent in the acidic isozymes, which accumulate extracellularly. Northern blot hybridization showed that genes encoding acidic and basic beta-1,3-glucanases are strongly induced after tobacco mosaic virus infection or salicylate treatment of tobacco. The cloning of these genes is a first step toward the identification of regulatory elements involved in their coordinate induction.
Infection of Nicotiana tabacum var. “Samsun” and “Samsun NN” with tobacco mosaic virus “Wageningen” U 1 (TMV W U 1) at 30 °C leads to systemic mosaic symptoms in both varieties. Electrophoretic patterns of soluble leaf proteins in polyacrylamide gels showed identical changes for both varieties and were the same as those in the combination TMV W U 1-Samsun at 20 °C and similar to those in the combination TMV W U 1-Samsun EN, in which identical symptoms are induced. Four new protein components (I to IV) accumulating at 20 °C in Samsun NN plants showing local lesions did not increase in amount after transfer of these plants to 30 °C; bands I, II and IV were considerably reduced, whereas band III appeared unaffected.When Samsun plants were infected with the Holmes' ribgrass strain of TMV (TMV HR) at 20 °C, both free TMV HR coat protein and relatively small amounts of the new components I to IV were apparent, proving that these components cannot be products of the N gene. The formation of small local lesions on the variety Samsun EN upon infection with TMV HR resulted in induction of the new components I to IV in apparently trace amounts, whereas quantitative changes seemed to be extremely limited. Inoculation of Samsun NN plants with TMV HR led to symptoms under greenhouse conditions only. In this combination, systemic acquired resistance was expressed when traces of protein components I to IV were present. In general, the changes in soluble proteins were connected with the type of symptoms—either mosaic or localized necrosis—produced, rather than the genetic make-up of the host plant variety.
As found earlier, supply of EDTA was obligatory for both flowering and satisfactory vegetative growth in Wolffia microscopica. It is now shown that the metal affecting growth and flowering is most probably iron. Omission of Fe but not of Cu, Zn, Mn and B from the medium markedly affects vegetative growth. There exists also a strong interaction between EDTA and Fe, one being largely inactive in the absence of the other. When Fe-EDDHA is substituted for Fe-citrate and EDTA in the medium, no great effect is seen in vegetative growth, but flowering takes place even under continuous light. Studies with (59)Fe show that, in the medium containing Fe-EDDHA, Fe uptake is stimulated several-fold; this is apparently associated with the flowering condition.
Salicylic acid and acetylsalicylic acid at concentrations of 10(-6)M to 10(-4)M effectively inhibit ethylene production by pear cell suspension cultures. Results suggest these acids act by blocking the conversion of 1-aminocyclopropane-1-carboxylic acid to ethylene.
The activity of the ethylene-forming enzyme (EFE) in suspension-cultured tomato (Lycopersicon esculentum Mill.) cells was almost completely abolished within 10 min by 0.4 mM of the metal-chelating agent 1,10-phenanthroline. Subsequent addition of 0.4 mM FeSO4 immediately reversed this inhibition. A partial reversion was also obtained with 0.6 mM CuSO4 and ZnSO4, probably as a consequence of the release of iron ions from the 1,10-phenanthroline complex. The inhibition was not reversed by Mn(2+) or Mg(2+). Tomato cells starved of iron exhibited a very low EFE activity. Addition of Fe(2+) to these cells caused a rapid recovery of EFE while Cu(2+), Zn(2+) and other bivalent cations were ineffective. The recovery of EFE activity in iron-starved cells was insensitive to cycloheximide and therefore does not appear to require synthesis of new protein. The EFE activity in tomato cells was induced by an elicitor derived from yeast extract. Throughout the course of induction, EFE activity was blocked within 10-20 min by 1,10-phenanthroline, and the induced level was equally rapidly restored after addition of iron. We conclude that iron is an essential cofactor for the conversion of 1-aminocyclopropane-1-carboxylic acid to ethylene in vivo.
Infection of the second true leaf (leaf 2) of cucumber with Colletotrichum lagenarium systemically protected the first true leaf (leaf 1) and leaf 3 from subsequent disease caused by the fungus. Protection of leaf 3 was consistently better than leaf 1. Excising the stem below the petiole of leaf 3 at the time leaf 2 was inoculated did not affect protection of leaf 1. When the petiole of inducer leaf 2 was girdled with cotton and hot water prior to inoculation with C. lagenarium, resistance was not induced in leaves 1 or 3. Similarly, when the petiole of inducer leaf 1 was girdled prior to inoculation with C. lagenarium, resistance was not induced in leaf 2. Resistance was not induced in leaf 2 if its petiole was girdled prior to the inoculation of inducer leaf 1. Inoculating leaf 5 with the fungus induced resistance in leaves 1 to 4 and 6 to 10, but protection was greater in leaves 9 and 10. Resistance was not induced in cucumber plants once they set fruit, and was markedly reduced when induced at the time of flowering.
SUMMARY Spraying tobacco plants with salicylic acid induces both the synthesis of 'pathogenesis-related' (PR) proteins and resistance to viruses that can induce necrotic lesions. We show that spraying Samsun NN tobacco with salicylic acid induced the production of PR-1 mRNAs and inhibited the systemic multiplication of alfalfa mosaic virus (A1MV) by 90%. Salicylic acid treatment also induced the synthesis of PR proteins in bean and cowpea plants, and reduced by 75 % the production of local lesions in A1MV-infected bean plants. Salicylic acid inhibited the replication of A1MV in cowpea protoplasts by up to 99%, depending on the mode of application. In A1MV- inoculated cowpea protoplasts, the production of viral minus-strand RNA, plus-strand RNA and coat protein was abolished, indicating that salicylic acid inhibits an early step in the A1MV replication cycle. The viability of the cells and the synthesis of host proteins were not affected by salicylic acid. Another aromatic compound, p-coumaric acid, induced neither PR proteins nor resistance to virus infection.
PREVIOUS investigations of the auxin metabolism in plant tissues led to the following findings of a ring hydroxylation resulting in 2-hydroxyindolyl-3-acetic acid1,2, and a hydroxynaphthalene-1-acetic acid, which probably hydroxylated in the 8-position, and their glucosidos2. Other known products of the auxin metabolism were the aspartic acid conjugates3 and the betad-glucose esters4,5 of the free auxinic acids. Analogues of the last two metabolites have also been described for benzoic acid4,6. In wheat coleoptiles no hydroxylation of benzoic acid could be demonstrated.
Trans-cinnamic acid, coumarin, salicylic acid, resorcinol, gallic acid, tannic acid and rutin counteracted the abscission-inducing
effect of ABA. This inhibitory action of phenolic compounds on ABA-induced abscission may indicate that they have a regulatory
role in the process.
The influence of 12 naturally occurring phenolic acids on the uptake of potassium by barley (Hordeum vulgare L. cv. Karlsberg) was examined using 86Rb-labelled potassium solutions. Without exception, all compounds tested, including both cinnamic acid and benzoic acid derivatives,
caused a significant reduction of uptake.
In addition, the inhibitory capacities of 15 variously substituted benzoic acids were determined over a range of different
concentrations of inhibitors. For each of these compounds an inhibition constant (Ki), defined as the concentration required to produce a 50 per cent reduction of uptake, was determined. The Ki values were found to be strongly correlated with the octanol-water partition coefficients of the compounds under examination.
It is clear from this study and previous work upon phosphate uptake that phenolic acids exert a generalized inhibitory effect
upon active ion-uptake which is almost certainly mediated through reversible alterations in membrane permeability.
Infection of plants by viruses can lead to a systemic or a localized infection. Systemic infections can produce protection against related viruses, as seen in the phenomenon of cross‐protection. The mechanisms thought to be involved are discussed. Localized infections also produce protection but against a wide range of unrelated pathogens, including bacteria and fungi. This involves an active response by the infected plants, switching on a number of different resistance mechanisms for the different types of pathogens. Research on these plant‐coded, induced proteins thought to be involved in resistance is discussed.
GA3 as well as SA increase the protein content of the stem and the leaves at 1 day under both 8- and 24-h photoperiods. A new
protein band with Rm 0.47 seems to be associated with floral bud initiation as it develops within 1–3 days in the stem as
well as in the leaves of plants exposed to inductive treatments regardless of whether the induction is caused by 8-h photoperiods
or by treatment with GA3 of SA under 24-h photoperiods. Another band with Rm 0.23 developed only in the stem of water-as well as GA3- or SA-treated plants under 8-h photoperiods. It may possibly be associated with extension growth.
The involvement of plastids in phenolic metabolism has been studied in Petunia after an isolation method of pure and physiologically intact chloroplasts has been adapted.Feeding experiments with [14C] phenylalanine demonstrated in these isolated organelles: the synthesis of cinnamate and benzoate derivatives which, with the exception of the first term of each serie, are o-hydroxylated (o-coumaric acid, coumarin and salicylic and gentisic acids); the lack of formation of labelled p-hydroxylated derivatives and flavanoids.The results are in agreement with the characterization, in the plastids of specific enzymes (PAL, cinnamate-2-hydroxylase) and the absence of cinnamate-4-hydroxylase.All these data suggest that the formation of p-hydroxylated derivatives, esters and flavonoids often characterized in chloroplasts may involve a cooperation between different organelles.
The duckweed, Lemna paucicostata 6746, is a short-day plant and is known to remain vegetative under long-day conditions in nutrient solutions containing EDTA. Lemna paucicostata, strain LP6, is a new strain in which so far it has not been possible to induce flowering in vitro either under SD or LD conditions. Here the induction of flowering is reported in both plants under otherwise non-inductive conditions by the use of salicylic acid, a phenol. Aspirin (acetylsalicylic acid) also brings about a similar effect. Flowering in Lemna paucicostata 6746 can be induced to the extent of 60% which is in contrast to an earlier report [1]. The effects of salicylic acid and aspirin on L. paucicostata LP6 are even more striking since almost 90–100% plants could be induced to flower.
By feeding ortho-3H cinnamic acid to Melilotus and ortho-3H cinnamic and benzoic acids to Gaultheria it has been shown that ortho-coumaric acid biosynthesis involves an efficient migration and retention of the ortho proton while salicylic acid biosynthesis involves a much lower retention.
Plants can be systemically immunized against diseases caused by fungi, bacteria, and viruses by restricted infection with fungi, bacteria, or viruses. Immunization followed by a booster inoculation protects cucumber, watermelon, and muskmelon throughout the season, and a single immunization protects cucumber against at least 10 unrelated diseases.
Occurence of PAL, cinnamate-hydroxylase and p-coumarate-hydroxylase, is found in cell-free extracts from Quercus pedunculata roots; moreover, an enzyme system which catalyzes benzoïc acid formation from cinnamic acid is caracterized for the first time. Role of these enzymes and their interactions within the same organ are discussed.
Gentisic acid has been shown to be one of the most commenly occurring aromatic acids of green plants. The systematic distribution
of the compound is described and its possible relationship lignification is discussed. Methods for its separation from other
phenolic constituents of plants and for the identification of the compound are described.
This paper deals with some properties of enzymes involved in the synthesis of phenolic acids, with special reference to their intracellular location. The results obtained can be summarized as follows: 1.1. Two phenylalanine ammonia-lyase isoenzymes coexist in Quercus roots as has been previously described for oak leaves. The cinnamate-sensitive isoenzyme is associated with the microsomal fraction whereas the benzoate-sensitive isoenzyme is located in the “F 10 000” fraction including mitochondria and microbodies.2.2. The cinnamate 4-hydroxylase, catalyzing p-coumarate formation, is tightly bound to microsomes and the “benzoate synthase”, an emzyme involved in the benzoic acid formation from t-cinnamate, is confined to the “F 10 000” fraction, presumably in microbodies.These data show that phenolic acids biosynthesis pathways are closely compartmented in organelles so that phenylpropanoid compounds are mainly formed in microsomes whereas C6−C1 acids are formed in microbodies. The regulation of these pathways seems to involve sophisticated mechanisms, associating isoenzymes with tight compartments.
We show here that Agrobacterium tumefaciens virulence (Vir) gene
expression is activated specifically by the plant molecules
acetosyringone (AS) and α-hydroxyacetosyringone (OH-AS). These
molecules induce the entire vir regulon in Agrobacterium as well as the
formation of T-DNA intermediate molecules. AS and OH-AS occur
specifically in exudates of wounded and metabolically active plant cells
and probably allow Agrobacterium to recognize susceptible cells in
nature.
METHYL salicylate has been found to occur both in the free
state1 and as the aglycone of a primeveroside,
gaultherin2 in Gaultheria procumbens L. (Ericaceæ).
IN the course of chromatographic studies on the phenolic constituents of Theobroma cacao L., an ultra-violet fluorescent compound (compound A), possessing an RF value of 0.28 in benzene/acetic acid/water, was shown to be widely distributed throughout the tissues of the plant1. This compound has now been shown to possess chromatographic and ultra-violet fluorescence properties identical with those of gentisic acid (2 : 5 dihydroxy benzoic acid). Chromatographic examination of a large number of leaf hydrolysates has revealed that gentisic acid is widely distributed in the plant kingdom, and it would appear to be one of the most commonly occurring aromatic acids of plant tissue. This acid, although usually present in very small or trace quantities, can readily be detected by the chromatographic technique described. The presence of other fluorescent aromatic acids, namely, caffeic, ferulic and sinapic acids in leaf hydrolysates has recently been reported2.
Cultured cells of Mallotus japonicus converted exogenous o-hydroxybenzoic acid into its O-glucoside after a lag period of 8 hr during which time the aglycone was taken up rapidly by the cells, partly excreted and then re-absorbed. The glucosylation of the aglycone into o-O-β-d-glucosylbenzoic acid began almost simultaneously with the induction of glucosyltransferase activity, and ca 78% of the aglycone administered was transformed into the glucoside in 12 hr. On the other hand, m- and p-hydroxybenzoic acids were glucosylated immediately after administration, the latter yielding both its O-glucoside and glucose ester. Inhibitor experiments suggested the possible participation of either 70S or 80S ribosomes in the glucosylation of isomeric hydroxybenzoic acids.
The 1-octanol-water partition coefficients are presented for 54 organic compounds. The additive-constitutive nature of the logarithm of partition coefficients is considered. It is postulated that intramolecular hydrophobic bonding can result in lower than expected values for partition coefficients in certain types of compounds.
Cloudberry (Rubus chamaemorus L.) is very resistant to deterioration by micro-organisms and has a good keeping quality. In the present study the natural content of some organic acids, often used as food preservatives, has been determined by gas chromatography. Benzoic acid was found in the greatest amount (about 50 mg/100 g cloudberry). Sorbic acid, salicylic acid, ϱ-hydroxy-, methyl-ϱ-hydroxy-and propyl-ϱ-hydroxy-benzoic acid were found in smaller amounts (less than 1 mg/100 g cloudberry).The amount of benzoic acid changes very little with the degree of ripeness or place of growth.
Injection of leaves of tobacco (Nicotiana tahacum cv. ‘Xanthi’ nc) with salicylic acid (SA) or phenylsene (PS) had an effect on the local lesion development caused by tobacco mosaic virus (TMV), depending upon the concentration used and the time interval between injection and challenge inoculation. Maximum reduction in lesion size was obtained with 0.75 mM SA or with 8 mM PS. Concentrations higher than 1 mM SA or 25 mM PS damaged the leaf tissue, PS being far less toxic than SA. The leaves responded rapidly to injection with SA or PS. A time interval of only 1 h between injection and TMV inoculation reduced the lesion size significantly. Isolated tobacco cell walls incubated with SA yielded carbohydrate fractions capable of reducing lesion size significantly after injection. Cell walls incubated without SA or with PS did not yield active carbohydrate fractions.
Die Biosynthese der Gentisinsure wurde mittels markierter Vorstufen in vier Arten hherer Pflanzen untersucht. Es konnte gezeigt werden, da Gentisinsure ber die Zwischenstufen Zimtsure, Benzoesure und Salicylsure gebildet wird. Die Hydroxylierung erfolgt hier erst auf der Stufe der Benzoesuren, whrend andere Hydroxybenzoesuren (z. B. 4-Hydroxybenzoesure und Vanillinsure) durch unmittelbaren Abbau aus den entsprechend substituierten Zimtsuren entstehen.Biosynthesis of gentisic acid was investigated by the use of labelled precursors in four species of higher plants. We showed that gentisic acid is formedvia the intermediates cinnamic, benzoic, and salicylic acid. Thereby hydroxylation occurs at the benzoic acid level, whereas other hydroxybenzoic acids (e.g. 4-hydroxybenzoic and vanillic acid) originate by immediate degradation of correspondingly substituted cinnamic acids.
Abscisic acid, a potent growth inhibitor inhibits hypocotyl growth ofRaphanus sativus seedlings. Phenolic compounds,viz., trans-cinnamic acid, chlorogenic acid, ferulic acid, salicylic acid, tannic acid and quercetin when applied with ABA, antagonize ABA action and restore normal seedling growth.
Gibberellic acid promotes hypocotyl growth and on combined application with ABA, the ratio of their concentrations determines the course of the resultant growth. This interaction can be modulated by phenolic compounds. Phenolic compounds in low concentrations when present together with GA and ABA, favour GA-induced growth by antagonizing the inhibitory influence of ABA.
The inhibitory action of abscisic acid on a wide range of growth processes is so far known to be reversed only by growth promoting hormones,viz., IAA, GA and cytokinins. Antagonistic action of phenolic compounds towards ABA, and increasing the action of GA when present together with GA and ABA, establishes a dual role to this class of compounds; balancing the effect of both growth promoting and growth inhibiting hormones.
Ethylene production by apple discs is effectively inhibited by salicylic acid. Inhibition is pH dependent, being greatest
from pH 3.5–4.5 and minimal at pH 6.5 and above. With 100 μM salicylic acid maximal inhibition, approximately 90%, is achieved
in 3 h with an apparent Ki of 40 μM. At somewhat higher concentrations salicylic acid also inhibits the conversion of 1-aminocyclo-propane-1-carboxylic
acid to ethylene by pear discs and mung bean hypocotyls. Salicylic acid interferes with action of the putative ethylene-forming
enzyme and in this respect is somewhat more effective than cobalt ion. The inhibitory effects of salicylic acid and cobalt
ion are not additive. Implications for the limits and locus of salicylic acid inhibition are discussed.
Aqueous salicylate solutions stimulated ethylene formation only when injurious, or potentially injurious, concentrations were
exogenously supplied to soybean cuttings. Stimulation occurred via the biochemical sequence involving ACC as an intermediate,
and was attributable to stimulation of ACC synthesis but not of EFE activity. Similar results were obtained by testing wound-induced
ethylene, whereas the production of virus-induced ethylene was not affected by salicylate. Prolonged salicylate treatments
which did not produce evident injurious effects inhibited soybean growth and rooting, probably through the moderate antiauxinic
property attributable to salicylates. These findings are discussed in relation to other results obtained from similar or different
plant materials.
Residues from corn and rye plants were allowed to decompose in soil for periods up to 30 days at 22–23 C, and the identity of some of the compounds produced as well as their relative phytotoxicity to lettuce seed and seedlings were determined. Paper, thin-layer, and gas chromatography were the principal methods used to identify the various compounds formed. The identities were confirmed by comparison with known synthetic compounds. Eighteen compounds were identified in the decomposing corn residues. Of these, salicylaldehyde, and butyric, phenylacetic, and 4-phenylbutyric acids were volatile, and benzoic,p-hydroxybenzoic, vanillic, ferulic,o-coumaric,o-hydroxyphenylacetic, salicylic, syringic,p-coumaric,trans-cinnamic, and caffeic acids were not volatile. Resorcinol,p-hydroxybenzaldehyde, and phloroglucinol were also found. In the decomposing rye residues, nine compounds were identified, including vanillic, ferulic, phenylacetic, 4-phenylbutyric,p-coumaric,p-hydroxybenzoic, salicylic, ando-coumaric acids, and salicylaldehyde. In the lettuce seed bioassay, most of the above compounds from corn and rye decomposition products exhibited some phytotoxicity. Phenylacetic, 4-phenylbutyric, salicylic, benzoic, ando-hydroxyphenylacetic acids were highly inhibitory to the growth of lettuce at concentrations between 25 and 50 ppm. The others reduced growth significantly at 100 ppm. Most of the phototoxic spots were located in theR
f
0.37–0.97 zone when developed in 2% acetic acid solvent.
Changes in the mitochondrial electrontransport chain were followed in the thermogenic inflorescence ofSauromatum guttatum Schott from 5d before thermogenesis to 3d thereafter. The capacities of the alternative and cytochrome pathways of mitochondrial electron transport were found to be developmentally coordinated to contribute to the thermogenic events in the appendix and the sterile floral regions. Electron flow through the alternative pathway, is believed primarily responsible for heat production, and this pathway was expressed to the highest degree in both tissues during thermogenesis. In the appendix, the cytochrome chain was shut down considerably during thermogenesis, forcing electron flow through the alternative pathway and thus yielding maximum heat production. The shut-down of the cytochrome chain does not occur in the sterile floral region which may explain why this region is not as thermogenic as the appendix. Cytochrome-oxidase difference spectra indicated that the cytochrome oxidase of appendix mitochondria was not capable of accepting electrons on the day of thermogenesis, and that this capacity was partially restored by the following day even though the tissue was senescing at this time point. Relative levels of messenger RNAs for cytochrome-oxidase subunits I and II were found to decrease the day before thermogenesis, which could result in lower levels of these proteins in appendix mitochondria on the day of thermogenesis.
The capacity for overall mitochondrial protein synthesis was also investigated and was found to drop continuously from 5d before thermogenesis to 3d thereafter, even though the capacities of the electron-transport chain were changing dramatically. The levels of mitochondrial ribosomal RNA levels decreased during development, which could explain the overall drop in mitochondrial translational efficiency. Experiments concerning the synthesis of the alternative-oxidase proteins indicated that they were most likely nuclearly encoded, and that their expression could be induced by salicylic acid.
Inoculation of half-leaves of Nicotiana tabacum var. Samsun NN, with tobacco mosaic (TMV) virus induced a high level of resistance to TMV in the opposite half-leaves. Challenge inoculation with TMV of the resistant half-leaves 7 days after the first inoculation resulted in limited lesion formation; the lesions were consistently only one-fifth to one-third as large (in diameter) as were lesions in susceptible half-leaves, and they usually were fewer in number. Similarly, inoculation of lower leaves on a plant induced resistance in upper leaves and vice versa. Resistance was first detected in 2–3 days, reached a maximum in about 7 days, and persisted for at least 20 days. The uninoculated resistant leaves or half-leaves proved to be free of virus. The highest level of resistance developed when plants were kept at 20°C before and after the challenge inoculation. Resistance could be detected in plants kept at 29° after challenge. Complete protection was not obtained by increasing the ratio of the area first inoculated to that challenged. Resistance was induced by mixed infections by TMV and potato virus X (PVX), but leaves highly resistant to TMV alone were only slightly resistant when challenged with TMV plus PVX. Resistance was induced by TMV infection in detached leaves, in excised shoots, and in plants kept in the dark 2 days before challenge inoculation. No resistance was induced by mechanical or chemical injury or by viruses that do not cause necrosis.The resistance induced by TMV is not specific for TMV. Leaves with TMV-induced resistance were resistant not only to TMV but also to tobacco necrosis virus, to turnip mosaic virus, and to tobacco and tomato ringspot viruses. The resistance was not as effective against these viruses as against TMV, but each of these local-lesion viruses induced a resistance in Samsun NN tobacco indistinguishable from that induced by TMV.
A pathogenesis-related (PR) protein was found in both the infected and the uninfected leaves of cucumber plants inoculated on the first true leaf with a fungal, a bacterial or a viral pathogen. This host-coded protein was detected up to five leaves above the infected leaf. The protein was purified from the intercellular fluid by ion-exchange chromatography and by high performance liquid chromatography on ion-exchange and phenyl-sepharose columns. The purified PR-protein was shown to be a chitinase with a molecular mass of 28 000 as determined by SDS-polyacrylamide gel electrophoresis and by gel filtration.
Radioactive p-hydroxybenzoic, vanillic and syringic acids were shown to be synthesized in a variety of plants from the corresponding hydroxycinnamic acids labelled in the β-position. Decarboxylation of the hydroxybenzoic acids indicated that nearly all the activity was contained in the carboxyl carbons. In addition to the formation of C6-C1 acids by removal of a 2-carbon fragment from C6-C3 acids, some species were capable of O-methylating protocatechuic to vanillic acid or hydroxylating it to yield gallic acid. Demethoxylation of sinapic and dehydroxylation of caffeic acid occurred in some species. Ortho hydroxybenzoic acids were shown to arise from phenylalanine and cinnamic acid.
The synthetic chelating agent EDDHA (ethylenediamine-di-o-hydroxyphenylacetic acid) and salicylic acid (SA) induce or enhance flowering in Lemna gibba L., strain G3, and Pistia stratiotes L. In L. gibba G3 these compounds also induce gibbosity, a swelling of the lower side of the fronds. EDTA (ethylenediaminetetraacetic acid) brings about similar effects in L. gibba G3. However, it is markedly less effective than EDDHA and SA and there are strong arguments in favour of a recent conclusion that it brings about its effect via a different mechanism. Ethylene induces gibbosity in L. gibba G3, however, neither in this species nor in P. stratiotes does it affect flowering. The effect of EDDHA/SA as well as ethylene on L. gibba G3 is specifically negated by autoclaved GA3 is i.e., break-down products of GA3 such as allogibberic acid, whereas non-autoclaved GA3 is ineffective. On the other hand GA3 induces profuse flowering in P. stratiotes whereas autoclaved GA3 is less effective. In the light of the various results it could be hypothesized that a gibberellin and ethylene in combination with another factor are involved in flowering of L. gibba G3.
The response of tomato plants to injury or to treatment with cell wall fragments has been studied. Wounding, pectic fragments or chitosan causes the systemic accumulation of proteinase inhibitor proteins. This response can be inhibited by pretreatment of the plants by aspirin. The effect of aspirin is rapid and reversible. Related hydroxybenzoic acids are also inhibitory: the structural specificity required for inhibition is very similar to that demonstrated by others to be required for induction of pathogenesis-related proteins in tobacco.