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Using of endophytic Saccharomycopsis fibuligera and thyme oil for management of gray mold rot of guava fruits
Abstract
The study deal with potentiality of Saccharomycopsis fibuligera and essential oils for controlling the gray mold rot of guava fruits. Botrytis cinerea was identified morphologically, at molecular level and then its pathogenicity was tested. Moreover, the endophytic yeast S. fibuligera was isolated from asymptomatic guava fruits and genetically identified. S. fibuligera successfully showed suppressive effect on B. cinerea comprising 48.52%, while thyme oil (among 8 tested oils) showed the highest inhibitory impact producing 26 mm inhibition zone at MIC value 0.2 µl/ml. 90.04% of total constituents of thyme oil was identified via GC-MS analysis. The major components were carvacrol, γ-terpinene, p-cymene and thymol. In vivo, thyme oil and S. fibuligera caused significant reduction in the disease comprising 78.6 and 67.9%, respectively. In conclusion, our study confirmed that thyme oil and S. fibuligera individually may be applied as future ecofriendly alternatives to synthetic fungicides for controlling the disease.
... In addition, the application of microbial antagonists as biocontrol agents in managing postharvest fruit diseases is considered to be an environmentally safe and promising tactic [17]. Many antagonistic microorganisms-including bacteria, fungi, and yeastsshow high efficiency against various postharvest fruit diseases [18][19][20]. For B. cinerea grey mold disease management, the current study aimed to investigate the efficiency of both preen (uropygial) oil-extracted from chicken feathers-and the endophytic bacteria Bacillus safensis, as safe and effective alternative biocontrol agents against B. cinerea, as well as to investigate the impact of combined antagonistic bacteria and preen oil for the biocontrol of B. cinerea grey mold disease. ...
... In addition, the application of microbial antagonists as biocontrol agents in managing postharvest fruit diseases is considered to be an environmentally safe and promising tacti [17]. Many antagonistic microorganisms-including bacteria, fungi, and yeasts-show high efficiency against various postharvest fruit diseases [18][19][20]. For B. cinerea grey mold disease management, the current study aimed to investigate the efficiency of both preen (uropygial) oil-extracted from chicken feathers-and the endophytic bacteria Bacillu safensis, as safe and effective alternative biocontrol agents against B. cinerea, as well as t investigate the impact of combined antagonistic bacteria and preen oil for the biocontro of B. cinerea grey mold disease. ...
... Three plates were used as replicates for each concentration. Minimum inhibitory concentration (MIC) was estimated as the lowest concentration of preen oil that inhibited the pathogen growth on the agar plates [19]. ...
Recently, there have been urgent economic and scientific demands to decrease the use of chemical fungicides during the treatment of phytopathogens, due to their human health and environmental impacts. This study explored the biocontrol efficacy of novel and eco-friendly preen (uropygial) oil and endophytic Bacillus safensis in managing postharvest Botrytis grey mold in strawberry fruit. The preen oil (25 μL/mL) showed high antifungal activity against B. cinerea Str5 in terms of the reduction in the fungal radial growth (41.3%) and the fungal colony-forming units (28.6%) compared to the control. A new strain of Bacillus safensis B3 had a good potential to produce chitinase enzymes (3.69 ± 0.31 U/mL), hydrolytic lipase (10.65 ± 0.51 U/mL), and protease enzymes (13.28 ± 0.65 U/mL), which are responsible for the hydrolysis of the B. cinerea Str5 cell wall and, consequently, restrict fungal growth. The in vivo experiment on strawberry fruit showed that preen (uropygial) oil reduced the disease severity by 87.25%, while the endophytic bacteria B. safensis B3 reduced it by 86.52%. This study reports the efficiency of individually applied bioagents in the control of phytopathogenic fungi for the first time and, consequently, encourages their application as a new and innovative strategy for prospective agricultural technology and food safety.
... They can be used to control postharvest pathogens and preserve fruit quality. Essential oils consist of various volatile compounds that act synergistically and exhibit antifungal and antimicrobial effects (Abdel-Rahim and Abo-Elyousr, 2017). Numerous opportunities exist for exploring their utility in the management of postharvest diseases with a wide range of natural fungicidal plant volatiles (Blasi and Cossignani, 2020). ...
This study investigated the effect of thyme, cinnamon, and oregano essential oil treatment (spraying and fumigation) on gray mold (Botrytis cinerea) and the quality of Taify table grapes in cold storage. Fruit were sprayed with 0.5% and 1% concentrations, fumigated with 2% or 4% concentrations, and stored at 2 °C ± 1 °C for 4 weeks. Compared with the untreated controls, all treatments had a stronger effect on quality maintenance. In addition, spraying was more effective than fumigation. Fruit sprayed with oregano oil with 1% concentration exhibited the least weight loss, decay, infection, and physical damage. They also exhibited the least changes in soluble solid content, vitamin C, and berry coloring. The second most effective treatment was spraying with cinnamon oil with 1% concentration. Furthermore, all treatments reduced the natural occurrence of B. cinerea. The highest reductions were observed in the oregano treatments (spraying with 1% and 4% concentrations). The lowest reductions were observed in the thyme treatments (spraying with 0.5% and 1% concentrations). The lowest levels of peroxidase and polyphenol oxidase enzymes were observed in the treatments with oregano (spraying with 0.5% and 1% concentration) and cinnamon (spraying with 1% concentration). Our results suggest that cinnamon and oregano essential oils could be used as natural antifungal compounds during postharvest storage.
... The main strategy to control anthracnose in banana has been the application of synthetic fungicides (e.g., trifloroxistrobine, tebuconazole and thiabendazole) in the field and during the postharvest period. However, the excessive use of synthetic fungicides has been associated with induction of antimicrobial resistance in phytopathogenic fungi, besides of a growing consumer concern regarding their harmful effects on human health and environment (Abdel-Rahim & Abo-Elyousr, 2017;Cindi et al., 2015;Farzaneh et al., 2015;Khaliq et al., 2019). Consumers have progressively increased the preference to foods preserved with natural components and refused to consume foods formulated or preserved with chemically synthesized compounds Vilaplana et al., 2018). ...
Aim:
This study evaluated the inhibitory effects on mycelial growth and damage on membrane integrity and enzymatic activity caused by Conyza bonariensis essential oil (CBEO) on distinct pathogenic Colletotrichum musae isolates, as well as the preventive and curative effects of coatings with gum Arabic (GA) and CBEO to reduce anthracnose development in banana during room temperature storage. The effects of GA-CBEO coatings on some physicochemical parameters of banana were investigated during room temperature storage.
Method and results:
CBEO (0.4 - 1 μl ml-1 ) inhibited the mycelia growth of C. musae isolates in laboratory media. The exposure of C. musae conidia to CBEO (0.6 μl ml-1 ) for 3 and 5 days resulted in high percentages of conidia with damaged cytoplasmic membrane and without enzymatic activity. Coatings with GA (0.1 mg ml-1 ) and CBEO (0.4 - 1 μl ml-1 ) reduced antrhacnose development in banana artificially contaminated with C. musae during storage. In most cases, the disease severity indexes found for GA-CBEO coated banana were lower than or similar to those found for banana treated with commercial fungicide. GA-CBEO coated banana had reduced alterations in physicochemical parameters during storage indicating more prolonged storability.
Conclusion:
The application of GA-CBEO coatings is effective to delay the anthracnose development in banana during storage, which should help to reduce the amount of fungicides used to control postharvest diseases in this fruit.
Significance and impact of the study:
This is the first study showing the efficacy of coatings formulated with GA and CBEO to delay the development of anthracnose in banana, as well as to decrease alterations in physicochemical parameters indicative of postharvest quality of this fruit during storage. In a practical point of view, GA-CBEO coatings could be innovative strategies to delay the antrachnose development and postharvest losses in banana.
... Four sets of test tubes were prepared and then incubated individually at 28 • C for 0 h, 1 day, 2 days, and 4 days, respectively. According to the modified method of [23], wounded apple fruits were aseptically and individually inoculated with 200 µL of each set of the treated pathogen inoculum and then allowed to dry for 1 h. Next, all the inoculated fruits were placed separately in surface sterilized plastic plates in a humid chamber and then covered with aluminum foil. ...
This study aimed to green synthesize nanosilver (AgNPs) using black tea extract and use it as a nanopreservative to increase the shelf life of stored apple fruits. Ultraviolet visible absorption (UV–vis) analysis of AgNPs recorded two λ max values at 260 and 452 nm. Transmission electron microscope and dynamic light scattering analyses showed that AgNPs are spherical in shape and have an average size of 20 and 170.6 nm, respectively, with a zeta potential of −20.06 mV. An in vitro assay confirmed the antifungal potential of AgNPs against M. fructigena when applied at 200 mg/L and preincubated for 4 days, reducing the radial growth by 96.1%. At the same dose and preincubation period, AgNPs caused a significant reduction in the diameter and fresh weight of brown rotted lesions in apple fruits artificially coinoculated with the pathogen by 77.4% and 84.4%, respectively. AgNPs caused the leakage of proteins and DNA from M. fructigena conidia and did not express cytotoxicity against the human HaCaT cell lines. Accordingly, green synthesized AgNPs are eco-friendly and economical and do not pose harm to human health; thus, they could be used as an effective nanopreservative in apple fruit stores to reduce the incidence of brown rot disease.
... On the other hand, EF and coating derived from plant-based natural products, including natural polymers (proteins, polysaccharides and lipids) and plant-derived secondary metabolites (i.e. essential oils), have been reported to have a very important role in fruit storage (Abdel-Rahim and Abo-Elyousr, 2017;Chen et al., 2019;Ju et al., 2019;Riva et al., 2020). These materials are environmentally friendly with high biodegradability (Nor and Ding, 2020) and correct use of them may have no negative impacts on human health. ...
Prevention of the postharvest losses had been a very important issue for the
scientific world for many centuries, where it was believed to help reaching sustainability in
horticultural production and prevention of hunger around the world. The main means of
deteriorations at fruits which may occur after harvest include physiological changes/losses,
physical losses, bio-chemical changes, changes in enzymatic activities and pathological
deterioration. Among these, diseases cover the most important part, where the losses due to
the diseases range from 5% to 20% which may reach to more than 50% at some susceptible
cultivars. Fungicides had been the most important tool for the management of the
postharvest diseases for many years, together with hygiene, cold storage and packaging.
However, due to the scientifically confirmed hazards of agro-chemicals on environment
and human health, the acceptability of the agro-chemicals had decreased and scientists
turned their face to natural alternatives. Most of the tropical and subtropical fruits contain
superficial cuticle, which helps fruits to regulate respiration and transpiration and to protect
against microbial decay. However, the waxy cuticle is generally being removed or damaged
during washing or other handling practices. Therefore, the application of protective
coatings (including wax) has been used in fruits industry since the twelfth century, against
microbial decay and for maintaining postharvest quality. This review aimed to summary
and discussed the main natural products used for this purpose to provide broad in scope
guide to farmers and fruit storage sector.
... Targeting the flower microbial community to shape the fruit microbiota for a biocontrol phenotype might be a promising way to manage postharvest pathogens. The use of endophytic beneficial microorganisms is rising in the biocontrol of fruits and vegetables (Abdel-Rahim and Abo-Elyousr, 2017;Calvo-Garrido et al., 2019;Kumar et al., 2021;Morales-Cedeño et al., 2021;Rivera Chávez et al., 2019;Vilanova et al., 2018). Some of them are also epiphytic and can be used as biocontrol agents. ...
Harvested fruits and vegetables are threatened by pathogens which can cause losses for up to 55 % depending on the fruit and country. A potentially sustainable control method is the biological control of these postharvest diseases using biocontrol agents (BCA). Nevertheless, the lack of reliability in practical conditions compared with synthetic chemical pesticides is a major hinderance. Strategies combining BCA application to nutrient additives, salts, edible coatings, or physical treatments have been evaluated to improve BCA antagonism activity, but with only relative success. The fruit surface is colonized by complex microbial communities that are often resilient. In a such environment, BCA establishment might be difficult. The integration of the role of microbial communities to assemble a BCA-friendly microbiota, is a promising solution to manage the reliability of BCA in real condition. Biocontrol phenotype of a microbiota is a complex metabolic phenotype that can be broken down in a multiple process supported by a network of beneficial microorganisms and molecules. Combining BCA application in a suitable complex biocontrol mix including for example beneficial helper strains, essential macro and micronutrients also acting as prebiotic of biocontrol could help the establishment of BCA in the epiphytic microbial network. At the same time, it could achieve a biocontrol efficacy and reliability comparable to synthetic chemical pesticides. In addition, the timing of beneficial microbial application has been reviewed based on the available literature. For example, we propose that shifting application at flowering stage (to induce a “path dependency”) could be considered for the future management of postharvest disease of fruits and vegetables. This application moment shift could be extended to other plant organ like seeds.
... Moreover, S. fibuligera can generate aromas and esters, which can improve the quality of liquor [7]. Furthermore, studies showed that S. fibuligera exerts an inhibitory effect on guava grey mould [8]. Therefore, as a strain with multifunctional properties, the study of S. fibuligera in liquor production has important academic significance and practical value. ...
Saccharomycopsis fibuligera, also known as Endomyces fibuliger or Saccharomyces fibuligera, is a yeast that produces ascospores and is widely found in all types of fermentation starters. It secretes α-amylase, β-glucosidase and acid protease with high efficiency and is an important functional microorganism in the fermentation of grains. Hence, S. fibuligera has high industrial application value; for example, it has a high starch conversion capacity and can synthesise trehalose from starch and it can decompose and synthesise single-cell proteins from starch and use proteins as a protein feed. It also produces aromas, esters and alcohols via fermentation; thereby, improving liquor quality. Moreover, S. fibuligera exerts an inhibitory effect on guava grey mould and can synthesise fungicides. Because S. fibuligera has excellent development potential and research value in industrial production, it has attracted considerable attention. In this study, the physicochemical, enzymatic and ester-producing properties of S. fibuligera and its effect on liquor flavour were examined. These findings will help screen excellent strains, optimise liquor fermentation conditions and improve liquor production quality.
... In 2017, the state recorded 7 tons of guava produced over an area of approximately 670 ha -1 (IPARDES, 2019). Several studies around the world, aim of improving guava management techniques and production (Salazar et al., 2006;Rezende et al., 2015;Abdel-Rahim and Abo-Elyousr, 2017;Moon et al., 2018;Adhiambo et al., 2019;Blanco et al., 2019). The purpose of the present work was to carry out climatic risk agricultural zoning for guava in Paraná river basin 3, a drainage area on the left bank of the Itaipú reservoir located between the Iguaçu and Piquiri rivers. ...
Fruticulture constitutes an important sector of the Brazilian agricultural industry. Despite technological and scientific advances, climate is still the most important variable defining crop productivity. Because of this, agroclimatic zoning should be one of the first factors to consider when starting to plant a particular crop. The objective of this work was to conduct climate risk zoning for guava (Psidium guajava L.) in Paraná river basin 3, Paraná, Brazil, using meteorological data from 43 stations collected between 1976 and 2018. The climate risk analysis was based on the climatic factors that impact the species, such as rainfall, annual water deficit, average annual temperature, coldest month temperature, and risk of frost. The findings of this study suggest that the basin has areas with a low climate risk for guava cultivation. Precipitation and water balance were sufficient under all tested scenarios. The most limiting factor for production was frost, but with risk only present during the first years of cultivation. Despite this, planting restrictions were only predicted to occur in the far west portion of the basin. Agricultural techniques that reduce the risk of frost and avoiding areas with greater frost incidences are the two most important aspects to consider to ensure greater success for guava in the region.
... The antagonistic efficacy of the yeast isolates was determined using the dual culture method as described by Abdel-Rahim and Abo-Elyousr (2017). Agar disks containing actively growing mycelium of the pathogen were individually placed at the centre of petri plates with PDA medium between two parallel streaks of each tested yeast isolate (3 cm apart). ...
In this study; an isolate of Monilinia fructigena the causal agent of apple fruit brown rot was isolated from rotten apple fruits cv. Golden delicious. In the in vivo pathogenicity assay, it presented significant disease incidence on the inoculated apple fruit, thus confirming its virulence. Five endophytic yeasts were isolated from healthy apple fruits; identified according to their microscopic characteristics as; Schwanniomyces vanrijiae, Galactomyces geotrichum, Pichia kudriavzevii, Debaryomyces hansenii, and Rhodotorula glutinis. The first three isolates showed appreciable inhibitory potential against M. fructigena by in vitro test; moreover, they caused a significant inhibition of germination of pathogen conidia by 67.6-89.2%. Identification of these three potent yeasts in addition to M. fructigena isolate was confirmed by PCR analysis through amplification of ITS region. In in vivo assays, fruits were inoculated with each of the 5 BCAs and M. fructigena simultaneously; 24 h before, and 24 h after pathogen inoculation, showing a noticeable reduction of disease incidence by 84.02-89.5%, 80.1-86.9%, 56.3-86.9% respectively, compared with the controls. By in vitro plate assays, BCAs were able to produce fungal cell wall hydrolyzing enzymes such as: chitinases, pectinases, β-1,3-glucanase, and protease, in addition to the production of a killer toxin. At 10 mg/L of Fe⁺³ in PDA, the three BCAs recorded significant in vitro inhibition of M. fructigena growth. The three potent BCAs do not express human pathogenicity traits. The aims of the current study were to isolate and characterize yeasts able to inhibit the growth of M. fructigena during apple storage.
... However, the curative activity was pathogen dependent, as was shown in several studies, where another yeast strain such as Metchnikowia pulcherrima had higher curative activity (43.3% lesion reduction) against C. acutatum than against P. expansum (no lesion reduction) on apples (Conway et al., 2004); or 100% of Botrytis cinerea inhibition and no inhibition of Cladosporium cladosporioides by M. pulcherrima were also observed on apples (Ruiz-Moyano et al., 2016). Better results were obtained in other studies concerning preventive activity, than in studies dealing with the curative action of yeasts against fruit pathogens (Mari et al., 2012;Tang et al., 2015;Abdel-Rahim and Abo-Elyousr, 2017;Liu et al., 2017). Therefore, in order to determine the real antagonistic potential of C. inconspicua and P. kluyveri it would be necessary to repeat this study testing the preventive activity against A. alternata and C. musae. ...
Biological control is one of the best strategies to reduce the use of chemical products during the postharvest period. The isolation and identification of potential biocontrol agents from fruit surfaces is the first step in obtaining an effective biological product against pathogens. In this study several yeast strains were isolated from Ecuadorian fruit and were identified. The curative activity of two selected yeasts, Candida inconspicua (CPN3) and Pichia kluyveri (B1), was analyzed to establish their antagonism against Alternaria alternata on yellow pitahaya and against Colletotrichum musae on organic banana. CPN3 yeast showed better effectiveness (p < 0.01) than B1 in controlling black rot on yellow pitahaya; whereas on organic banana B1 demonstrated better efficacy (p < 0.05) in reducing anthracnose than CPN3. This fact was related to the population dynamics of both yeasts during cold storage of yellow pitahaya and organic banana. No negative effects were observed on physicochemical quality of fruit treated with the potential biocontrol agents. Although curative activity was observed when using CPN3 and B1, studies about their preventive action are needed to establish the antagonistic potential of both yeasts.
... Yeasts have the ability to compete for space and nutrients, giving them an advantage as biocontrol agents for postharvest pathogens (Filonow 1998;Punja and Utkhede 2003;Kupper et al. 2013). Several published researches have shown the capability of yeasts to control postharvest fungal diseases (Platania et al. 2012;Kupper et al. 2013;Liu et al. 2013;Moretto et al. 2014;Abdel-Rahim and Abo-Elyousr 2017). According to the best of our knowledge there is no published data determining the biological control of yeast on potato soft rot diseases. ...
In this study, an antagonistic yeast isolate, Wickerhamiella versatilis was considered as a promising biocontrol agent against Pectobacterium carotovorum subsp. Carotovorum (Pcc) the causal agent of soft rot disease of potato. Antagonistic yeast inhibited the growth of Pcc in vitro, and reducing the soft rot severity of infected potato tubers (cv. Diamant) under greenhouse conditions. Consequently, cellulase and pectinase hydrolytic activities in infected potato tubers with yeast + Pcc were decreased compared with infected tubers with Pcc. The histological characterization of treated potato tubers with antagonistic yeast W. versatilis using scanning electron microscope showed the accumulation of extracellular substances that may induce plant resistant and protects potato tubers from hydrolysis and damages. This study may introduce the possibility of using the antagonistic yeast isolate, as a biocontrol agent against soft rot of potato tubers.
... In this study, we isolated a marine yeast ZMY-1 from the sea mud obtained at Zhangzhou Mangrove Reserve in Fujian province, China, which showed good inhibitory properties against B. cinerea (Fig. 1). B. cinerea can cause gray mold in many different fruits, including strawberries, tomatoes ( Zhang et al., 2017), table grapes (Ferreira, 1990), guava fruit ( Abdel-Rahim and Abo-Elyousr, 2017), and pears ( Nikkhah et al., 2017). Several yeasts exhibit inhibitory effects on B. cinerea, such as Cryptococcus albidus (Fan and Tian, 2001), P. guilliermondii In our present work, the marine yeast ZMY-1 was identified as Sporidiobolus pararoseus by molecular analysis, and named Sporidiobolus pararoseus ZMY-1 (Fig.2). S. pararoseus ZMY-1 effectively inhibits growth in vitro on PDA medium and in vivo in strawberry fruit. ...
... Thus, any potential control measure which can effectively delay symptoms of anthracnose infection would have an important role in extending the shelf life of bananas during storage (Maqbool et al., 2010) Chemical fungicides, like imazalil, are commonly used to control anthracnose in bananas during the postharvest period in order to prolong the shelf life of fresh fruit. Although the control of postharvest pathogens currently still relies mainly on the application of fungicides, because of the short time between treatment and consumption, there are strong public and scientific demands against the use of chemical fungicides in order to prevent carcinogenic impacts, residual toxicity, ecological pollution and particularly the fungicide-resistance development (Cindi et al., 2015;Farzaneh et al., 2015;Abdel-Rahim and Abo-Elyousr, 2017). ...
Anthracnose in organic bananas is an aggressive, difficult to control postharvest disease. Essential oils have been studied in order incorporate them into integrated pest management, and to reduce synthetic fungicides during the postharvest period. In vitro assays showed that thyme oil was the best essential oil to control mycelial growth of Colletotrichum musae. This essential oil was tested in vivo because of its fungicidal effect. The results showed that, after storage and shelf life at 20 °C, severity inhibition of C. musae on fruit treated with 500 μL L−1 of thyme oil (30.8%) was higher (p < 0.05) than with other treatments. Moreover, 500 μL L−1 of thyme oil reduced weight loss, retained color and firmness, and slowed the changes of chemical parameters in organic bananas during storage. After the postharvest period, panelists did not detect thyme oil odor, and overall appearance was also better, when using thyme oil, than in non-treated fruit. These results suggest that thyme oil may be potentially used for controlling anthracnose in organic bananas during the postharvest period, without a negative effect on its physicochemical and sensory quality.
Fruit diseases brought on by fungus infestation leads to postharvest losses of fresh fruit. Approximately 30% of harvested fruits do not reach consumers’ plates due to postharvest losses. Fungal pathogens play a substantial part in those losses, as they cause the majority of fruit rots and consumer complaints. Understanding fungal pathogenic processes and control measures is crucial for developing disease prevention and treatment strategies. In this review, we covered the presented pathogen entry, environmental conditions for pathogenesis, fruit’s response to pathogen attack, molecular mechanisms by which fungi infect fruits in the postharvest phase, production of mycotoxin, virulence factors, fungal genes involved in pathogenesis, and recent strategies for protecting fruit from fungal attack. Then, in order to investigate new avenues for ensuring fruit production, existing fungal management strategies were then assessed based on their mechanisms for altering the infection process. The goal of this review is to bridge the knowledge gap between the mechanisms of fungal disease progression and numerous disease control strategies being developed for fruit farming.
Plants host diverse microbial communities, which undergo a complex interaction with
each other. Plant-associated microbial communities provide various benefits to the host directly or
indirectly, viz. nutrient acquisition, protection from pathogen invaders, mitigation from different
biotic and abiotic stress. Presently, plant-associated microbial strains are frequently utilized as
biofertilizers, biostimulants and biocontrol agents in greenhouse and field conditions and have
shown satisfactory results. Nowadays, the plant/fruit microbiome has been employed to control
postharvest pathogens and postharvest decay, and to maintain the quality or shelf life of fruits. In
this context, the intervention of the natural fruit microbiome or the creation of synthetic microbial
communities to modulate the functional attributes of the natural microbiome is an emerging aspect.
In this regard, we discuss the community behavior of microbes in natural conditions and how the
microbiome intervention plays a crucial role in the postharvest management of fruits
As endophytes are widely distributed in the plant’s internal compartments and despite having enormous potential as a biocontrol agent against postharvest diseases of fruits, the fruit–endophyte–pathogen interactions have not been studied detail. Therefore, this review aims to briefly discuss the colonization patterns of endophytes and pathogens in the host tissue, the diversity and distribution patterns of endophytes in the carposphere of fruits, and host–endophyte–pathogen interactions and the molecular mechanism of the endophytic microbiome in postharvest disease management in fruits. Postharvest loss management is one of the major concerns of the current century. It is considered a critical challenge to food security for the rising global population. However, to manage the postharvest loss, still, a large population relies on chemical fungicides, which affect food quality and are hazardous to health and the surrounding environment. However, the scientific community has searched for alternatives for the last two decades. In this context, endophytic microorganisms have emerged as an economical, sustainable, and viable option to manage postharvest pathogens with integral colonization properties and eliciting a defense response against pathogens. This review extensively summarizes recent developments in endophytic interactions with harvested fruits and pathogens—the multiple biocontrol traits of endophytes and colonization and diversity patterns of endophytes. In addition, the upscale commercial production of endophytes for postharvest disease treatment is discussed.
In this study, we utilized pomegranate peel and marine algae Ulva lactuca (U. lactuca) as rich and sustained sources of bioactive compounds to combat tomato-black spot disease. n-Hexane extracts from the peel of pomegranate (Punica granatum)
(PPE) and the marine algal biomass U. lactuca (ULE) were used alone and in combinations to verify their impact against
Alternaria alternata (A. alternata). The applied extracts exhibited severe destructive efects on both fungal growth and
structure such as mycelia malformation, underdeveloped conidia, cell wall deformation, and shrinkage. Moreover, increased
deformations and protrusions, and notch-like structures, were noticed in A. alternata mycelia treated with mixed extracts
(PPE and ULE) compared to all other treatments. The protein and reduced sugar contents in tomato fruits were signifcantly
increased in the infected fruits with A. alternata. The highest enzyme activities of pectinase, cellulase, catalase (CAT), and
ascorbate peroxidase (APX) were recorded in infected tomatoes in comparison with the healthy ones. Molecular docking
studies showed that each extract is rich with bioactive compounds that have a promising inhibition efect on A. alternata
cellulases. Pomegranate and Ulva extract showed promising antifungal activity against A. alternata which revealed their
feasibility and applicability as biocontrol agents in postharvest disease management and food preservation against fungal
pathogens.
The control of plant diseases is still widely carried out through the use of synthetic chemicals. However, many fungal and bacterial pathogens have developed resistance to the active ingredients of a wide range of pesticides. In addition, the problems associated with their use (i.e., waste disposal) as well as the increasing public awareness regarding residues and environmental risks have promoted the search for new and safer alternatives. Thus, the replacement of chemical pesticides with non-toxic compounds for consumers and for the environment is gaining considerable attention worldwide. Lowering the loss of products can be achieved through the use of an integrated disease management program, which employs a variety of control means and methods with a focus on preventing, reducing, and eradicating predisposing/instigating factors.
In this Special Issue, we invite scientists and researchers to contribute research articles on the utilization of a range of alternative control strategies, such as biological control using antagonistic/beneficial agents; physical strategies using low temperatures, modified and controlled atmospheres, heat, and irradiation; and substances generally regarded as safe, such as sanitizers, plant extracts, and essential oils. Papers that concentrate on the integrated disease management of agricultural products are also accepted.
In this Special Issue, original research articles and reviews are welcome. Research areas may include (but are not limited to) the following:
Integrated strategies to control plant diseases;
Alternatives to reducing/substituting chemical pesticides;
Natural compounds to control plant diseases;
Physical means of managing plant pathogens/diseases;
The role of biocontrol agents in managing plant diseases;
Nanotechnology as a way to control plant diseases.
We look forward to receiving your contributions.
Prof. Dr. Youssef Khamis
Prof. Dr. Antonio Ippolito
Prof. Dr. Khaled A. El-Tarabily
Guest Editors
Banana and mango are the top commodities in the Philippines that are traded worldwide however, fungal diseases such as anthracnose affect their yield and quality. Environmentally sound control strategies have been explored and one of these is mycofumigation using fungal endophytes. This alternative approach is understudied in the Philippines, hence, the study aimed to evaluate the mycofumigation potential of fungal endophytes collected from Mt. Makiling, Luzon, Philippines and their pathogenicity to banana and mango fruits. In vitro and in vivo mycofumigation assays were conducted with a completely randomized design layout with triplicates per treatment under laboratory conditions. The fungal endophytes used as mycofumigants, Diaporthe sp. and Fusarium proliferatum, were comparatively effective in controlling the anthracnose of banana and mango. The mycelial growth for in vitro assay of Colletotrichum musae and Colletotrichum gloeosporioides were significantly reduced compared to the control when exposed to volatile organic compounds produced by the fungal endophytes. In addition, the results of the in vivo mycofumigation assay against C. musae showed Diaporthe sp. had a significantly higher inhibition rate (93%) than F. proliferatum (67%) when grown on potato dextrose agar plates. The bioefficacy of the Diaporthe sp. and F. proliferatum was improved when grown on peanut and corn seed substrates with a reduction of banana and mango anthracnose severity ranging from 82 to 100%. Cultures grown on corn substrate performed better than those grown on peanut. Pathogenicity tests also revealed that these endophytic fungi did not cause disease in the banana or mango fruits indicating their potential as good biocontrol agents against C. musae and C. gloeosporioides.
Aromatic plants and their extracts have gained acceptance as natural alternatives to conventional antimicrobial agents. However, essential oils (EOs) extracted from plants often do not exert sufficiently potent effects on account of extrinsic interference effects (e.g. sensitivities to light, oxygen, humidity, high temperatures, or UV radiation) and unfavorable intrinsic characteristics (e.g., hydrophobicity and volatility). The physical, chemical, and biological characteristics of EOs can be regulated by entrapment or by coating with other materials that protect them against harsh processes and unfavorable external conditions. Biodegradable polymer encapsulation technologies based on plant and animal extracts have significantly improved the sustained release of EOs and associated food preservation strategies. In this review, we discuss EO compounds, preparation methods pertaining to their encapsulation, and the applications of EO microcapsules in fruits and vegetables. We conclude by discussing the safety of these methodologies while also highlighting future insights in this field of research.
The current study aimed to evaulate the efficacy of hydrogen
peroxide, ammonium chloride and sulfur nanoparticles,
aqueous plant extracts of pelargonium, thyme and carnation
and Tilt 25% fungicide for controlling fabae bean rust disease
and investigate the induction of resistance of faba bean
plants against rust disease. All above treatments were tested
on urediniospores germination of Uromyces viciae-fabae in
vitro. Among the treatments used, hydrogen peroxide at
50 mM and pelargonium extract at 20% were the most effective,
which decreased of urediniospores germination 34.2
and 36.75%, respectively, than the other treatments. Spraying
of infected faba bean plants Spanish cultivar with all tested
treatments was effective in reducing disease severity of rust
disease under greenhouse and field conditions. The highest
reduction in disease severity was observed in case of Tilt
25% fungicide treatment, followed by hydrogen peroxide.
Furthermore, all treatments significantly increased total phenol
content and enzymes activity in treated plants compared
to untreated plants. Morevere, the application of these treatments
enhanced significantly all studied agronomic characters,
i.e., plant height (cm), number of pods per plant and
weight of 100 seeds (gm). The study indicated that these
treatments can be useful for the protection of faba bean
plants from rust disease, especially in clean farming.
The current study aimed to evaulate the efficacy of hydrogen
peroxide, ammonium chloride and sulfur nanoparticles,
aqueous plant extracts of pelargonium, thyme and carnation
and Tilt 25% fungicide for controlling fabae bean rust disease
and investigate the induction of resistance of faba bean
plants against rust disease. All above treatments were tested
on urediniospores germination of Uromyces viciae-fabae in
vitro. Among the treatments used, hydrogen peroxide at
50 mM and pelargonium extract at 20% were the most effective,
which decreased of urediniospores germination 34.2
and 36.75%, respectively, than the other treatments. Spraying
of infected faba bean plants Spanish cultivar with all tested
treatments was effective in reducing disease severity of rust
disease under greenhouse and field conditions. The highest
reduction in disease severity was observed in case of Tilt
25% fungicide treatment, followed by hydrogen peroxide.
Furthermore, all treatments significantly increased total phenol
content and enzymes activity in treated plants compared
to untreated plants. Morevere, the application of these treatments
enhanced significantly all studied agronomic characters,
i.e., plant height (cm), number of pods per plant and
weight of 100 seeds (gm). The study indicated that these
treatments can be useful for the protection of faba bean
plants from rust disease, especially in clean farming.
Fruit-based diets are recognized for their benefits to human health. The safety of fruit is a global concern for scientists. Fruit microbiome represents the whole microorganisms that are associated with a fruit. These microbes are either found on the surfaces (epiphytes) or in the tissues of the fruit (endophytes). The recent knowledge gained from these microbial communities is considered relevant to the field of biological control in prevention of postharvest fruit pathology. In this study, the importance of the microbiome of certain fruits and how it holds promise for solving the problems inherent in biocontrol and postharvest crop protection are summarized. Research needs on the fruit microbiome are highlighted. Data from DNA sequencing and "meta-omics" technologies very recently applied to the study of microbial communities of fruits in the postharvest context are also discussed. Various fruit parameters, management practices, and environmental conditions are the main determinants of the microbiome. Microbial communities can be classified according to their structure and function in fruit tissues. A critical mechanism of microbial biological control agents is to reshape and interact with the microbiome of the fruit. The ability to control the microbiome of any fruit is a great potential in postharvest management of fruits. Research on the fruit microbiome offers important opportunities to develop postharvest biocontrol strategies and products, as well as the health profile of the fruit.
Background
Green mold disease on citrus caused by Penicillium digitatum is the most serious and destructive disease. It is causing 90% of production losses during post-harvest handling.
Results
In this study, the activity of seven yeast isolates from lemons against P. digitatum , a fungal pathogen that causes the green mold disease in lemons, was isolated and examined. In vitro experiments showed that isolate three significantly reduced pathogen growths and were later identified as Schwanniomyces vanrijiae . In addition, 3% ethanolic extracts of propolis (EEP) caused a strong mycelial growth inhibition with inhibition halos of 1.4 cm. The use of S. vanrijiae treatments to protect lemon fruits from green mold has been reported (55%); however, reports describing the application of EEP are limited (40%). Thus, the effectiveness of the combination of S. vanrijiae and 3% EEP in an antagonistic mixture for protecting lemon fruits from P. digitatum was examined. EEP and S. vanrijiae treatments were applied alone and in combination in both in vitro and in vivo conditions. The combined application of 3% EEP + S. vanrijiae on lemon fruits significantly reduced the severity and incidence of green mold (80 and 93.7%, respectively) with much higher efficacy than either treatment alone. Lemon fruits treated with both S. vanrijiae and 3% EEP showed increased levels of antioxidants, peroxidase (POD), polyphenol oxidase (PPO), and phenol than the untreated control.
Conclusion
The results indicated that the combination of S. vanrijiae + 3% EEP can strongly protect lemon fruits from green mold compared with the sole application of either bioagent.
Southern corn leaf blight (SCLB) caused by Bipolaris maydis is an important foliar disease of maize. In this study, a nematode-symbiotic bacterium Xenorhabdus budapestensis strain C72 was identified with remarkable inhibiting effect on mycelial growth and spore germination of B. maydis. The in vitro assay revealed that C72 cell-free culture media (CFCM) with thermostability exhibited broad-spectrum antifungal activities against other several important plant pathogenic fungi. The early colonization of B. maydis were significantly impaired by CFCM treatment under phytotron condition. This antagonism is likely to be the main contributor to the highly efficient plant protection of 40% (v/v) CFCM treatment against B. maydis, and the relative control effect reached to 59.15% and 77.96% in greenhouse and field experiments, which was comparable to the effect of fungicides. Moreover, we found that extracellular enzymes secreted by symbiotic bacterium may be one of the reasons for the antifungal potential of C72. Beside direct antagonistic effects provided by the bacterium, defense related genes were induced in maize after CFCM treatment. In summary, this study reported the first systematic evaluation of the effect of X. budapestensis C72 in controlling SCLB and exploration of its mode of action, then indicating that entomopathogenic bacteria have the potential to become a new and efficient biological control resource for plant fungal disease management.
Bacillus species are promising agent for the biological control of postharvest diseases. This study investigated the bio-control efficiency of Bacillus halotolerans KLBC XJ-5 against grey mould caused by Botrytis cinerea in postharvest strawberries, together with its underlying antagonistic mechanism. Treatment with B. halotolerans KLBC XJ-5 controlled mycelial growth as well as conidial germination of B. cinerea in vitro. The grey mould in strawberries inoculated with B. halotolerans KLBC XJ-5 was lower in comparison with that in the control fruit after 4 d of incubation. Genome sequencing and further bioinformatic analyses suggested that strain KLBC XJ-5 harboured six antimicrobial biosynthesis gene clusters, besides four glycoside hydrolase family 18 gene clusters
involved in chitin degradation. In addition, it secreted the lytic enzyme chitinase (CHI). B. halotolerans KLBC XJ-5-treated strawberries exhibited significant induced enzyme activities (polyphenol oxidase, phenylalanine ammonia lyase, β-1, 3-glucanase, and chitinase) and compounds related to disease resistance (total phenols, flavonoids). Compared to the control fruit, B. halotolerans KLBC XJ-5-treated fruit did not present differences on nutritional quality (measured in ascorbic acid, titratable acidity, and total soluble solids). Thus, it can be concluded that B. halotolerans KLBC XJ-5 could be potentially useful as a suitable bio-control agent in harvested strawberries
Fungal pathogens Alternaria spp., Botrytis spp. and Colletotrichum spp. cause a significant loss of horticultural crops and their yield annually. The most convenient way for controlling diseases caused by these pathogens is the use of chemical fungicides. However, current practices still result in soil, water and air pollution, contribute to the loss of biodiversity and climate change, also are harmful to human health. Therefore, there is a growing demand for environmentally friendly plant protection methods. Herbs, especially, volatile oils, are a natural source of active ingredients. The findings of antimicrobial and antifungal activities, low toxicity, and biodegradability of essential oils make them potential for use in plant protection against pathogens instead of chemicals. This research aimed to evaluate the ability of Lamiaceae plants essential oils to suppress the growth of Alternaria spp., Botrytis spp., and Colletotrichum spp. in vitro. The study was carried out at the LAMMC Institute of Horticulture, Lithuania. Essential oils from lavender (Lavandula angustifolia) and thyme (Thymus vulgaris) were obtained by hydrodistillation and poured to potato dextrose agar medium at 200 1,000 L-1 concentrations. The radial colony growth of each pathogen measured after placing mycelial plugs of each fungus on Petri dishes. Results demonstrated that thyme essential oil significantly suppressed the growth of all three investigated fungal pathogens at concentrations starting from 400 L-1 7 days after inoculation as no growth of the pathogens observed. Meanwhile, lavender essential oil had lower antifungal activity than thyme. The most significant concentration of lavender essential oil was 1,000 L-1. To conclude, thyme essential oil showed high antifungal activity, and lavender essential oil showed moderate antifungal activity for our tested horticultural crop fungal pathogens. Both oils can be applied as one of the eco-friendly ways to control plant pathogens.
Each plant has a microbiome that is consisted of epiphytic and endophytic microbial communities. The plant microbiome may play a prominent role in different functions such as growth, disease, suppressing pathogens and potential influence of the physiology of reproductive plant organs (e.g., fruit). Endophytic microbiomes of any plant organs have mutualistic interaction between each other and functionally interact with each other in multiple ways. The distribution pattern of endophytic microbiota varies with each plant's organs and largely depends on plant genotype (i.e., cultivar) developmental stages, growth condition, biotic and abiotic factors. The distribution pattern, as well as the potential utilization of endophytic microbiota that are associated with internal tissues for managing pre and postharvest pathogens, is discussed in this chapter. Abstract Each plant has a microbiome that is consisted of epiphytic and endo-phytic microbial communities. The plant microbiome may play a prominent role in different functions such as growth, disease, suppressing pathogens and potential influence of the physiology of reproductive plant organs (e.g., fruit). Endophytic microbiomes of any plant organs have mutualistic interaction between each other and functionally interact with each other in multiple ways. The distribution pattern of endophytic microbiota varies with each plant's organs and largely depends on plant genotype (i.e., cultivar) developmental stages, growth condition, biotic and abiotic factors. The distribution pattern, as well as the potential utilization of endo-phytic microbiota that are associated with internal tissues for managing pre and postharvest pathogens, is discussed in this chapter.
Food loss of fruit and vegetables caused by postharvest diseases is a major issue worldwide. The method used to prevent and control postharvest diseases is usually to use chemical fungicides, whereas long-term and large-scale use will make the pathogens resistance and potentially have a negative impact on human health and ecological environment. Therefore, finding a safe and effective biological control method instead of chemical control is a hot research topic in recent years. Endophytes, colonizing plants asymptomatically, can promote the growth of the hosts and enhance their resistance. The use of endophytes as biological control agents for postharvest diseases of fruit and vegetables has attracted more and more attention in recent 20 years. Compared with chemical control, endophytes have the advantages of being more environmentally friendly, sustainable and safer, while there are relatively few relevant studies, herein, it is necessary to have a summary for available literatures. This review mainly focused on the recent progress about using endophytes to enhance the resistance of postharvest fruit and vegetables to diseases, with the emphasis on the possible mechanisms and the potential applications. Furthermore, this article puts forward the future studying area for using antagonistic endophytes to prevent and control of fruit and vegetable postharvest diseases: (1) screening more potential broad spectrum anti-pathogen endophytes and their metabolic active substance by the method of macro genomics; (2) elucidating the underlining molecular mechanism among endophytes, harvested vegetables and fruit, pathogens, and microbial communities; (3) needing more application research for overcoming the difficulties of commercialization practice. This article is protected by copyright. All rights reserved.
O Paraná é destaque no cenário agropecuário nacional, apresentando um grande potencial agrícola. A utilização de avançadas técnicas agronômicas e conservacionistas coloca o estado em destaque em termos de produtividade. Nesse cenário, a fruticultura é um dos mais notórios segmentos agrícolas brasileiros. Apresenta evolução contínua de produção, atendendo a crescente demanda interna e externa, além de ser um dos principais segmentos da agricultura familiar. Apesar dos recentes avanços tecnológicos e científicos, o clima é ainda a variável mais importante na produtividade agrícola. Estudos que evidenciem a variabilidade climática e o impacto no desenvolvimento fisiológico das espécies são fundamentais para o planejamento e calendário agrícola, visando a conservação de recursos e um manejo sustentável da produção. Nesse contexto, uma das primeiras informações a serem consideradas ao iniciar o cultivo de determinada cultura é o zoneamento de risco agroclimático, visto que este fornece informações de risco meteorológico, melhor época de semeadura e disponibilidade hídrica. Dessa forma, o objetivo desse trabalho foi realizar o zoneamento de risco agroclimático para espécies frutíferas na bacia do Rio Paraná 3, que contemplou as seguintes espécies frutíferas: abacate, abacaxi, banana, goiaba, lima ácida tahiti, mamão, manga, maracujá e uvas rústicas. Por meio do zoneamento é possível recomendar por cultura e área/município a viabilidade, períodos e época de plantio e colheita indicados por meio do zoneamento, além de determinar os riscos para cada espécie frutífera. Para isso foram utilizados dados meteorológicos de 43 estações com recorte temporal de 1976-2018. A análise do risco agroclimático foi pautada nas exigências edafoclimáticas de cada espécie, sendo utilizados os elementos meteorológicos de temperatura, geada, precipitação, insolação, soma térmica, umidade e informações geográficas (latitude, longitude e altitude). Foram aplicadas técnicas estatísticas e de geoprocessamento, como regressões e interpolações para garantir uma plena cobertura regional de informações e contribuir para a tomada de decisão na agricultura da região. Identificou-se grande discrepância em todas as variáveis meteorológicas analisadas mesmo sendo uma área relativamente pequena do Estado do Paraná. Por estar localizado em região de transição climática, toda a área apresentou aptidão agrícola e potencialidades para o cultivo de uma série de espécies frutíferas. Promovendo assim, uma maior biodiversidade para o campo da região e maior segurança para os produtores, visando a possibilidade de conseguirem financiamento e crédito agrícola por meio do zoneamento. Espacialmente observou-se que a região na borda do Rio Paraná, com menores altitudes, apresentou maior aptidão para boa parte das frutas tropicais. O fator da altimetria garantiu maiores temperaturas, e menores risco de geada, mesmo sendo uma área relativamente mais seca, quando comparada ao restante da bacia. A precipitação e o balanço hídrico se mostraram suficientes, em todos os cenários analisados para o cultivo de frutas. O elemento meteorológico que mais limita a produção de frutas na região foi a geada. Toda a região apresenta risco de geada, o que restringe o plantio de frutíferas na região com maiores altitudes, próximo a Cascavel. A combinação do período mais chuvoso do ano e maior tempo hábil para o desenvolvimento das espécies antes do risco da primeira geada, resultou na recomendação de plantio das espécies para o início da primavera, no mês de outubro.
Bacterial spot disease caused by Xanthomonas axonopodis pv. vesicatoria is considered one of the major diseases of tomato crop worldwide. The objective of this paper was to study the effect of certain essential oils (EOs), lemongrass, oleum and thyme, on X. axonopodis pv. vesicatoria (PHYX14) for controlling bacterial spot disease in tomato plants. The tested three essential oils (EOs) showed antibacterial activity in vitro test at 1:10 concentration against the PHYX14.Thyme oil exhibited the highest inhibition against PHYX14 followed by lemongrass and finally oleum. Under greenhouse conditions, the effect of EOs on the bacterial spot of tomato was evaluated on tomato seedlings. Thyme oil exhibited the highest reducing of tomato bacterial spot followed oleum and then lemongrass. Results indicated that the application of the tested (EOs) to tomato plants two days after the infection caused the highest reduction of disease severity. While the application of oleum oil exhibited the highest induction of the oxidative enzymes, peroxidase (PO) and polyphenol enzyme (PPO). Also increased total phenolic contents of tomato leaves followed lemongrass and then thyme oil as compared by control. The application of EOs two days before the infection caused the highest induction of PO, PPO enzymes and total phenolic contents in tomato leaves than two days after the inoculation.
Bacterial spot disease caused by Xanthomonas axonopodis pv. vesicatoria is considered one of the major diseases of tomato crop worldwide. The objective of this paper was to study the effect of certain essential oils (EOs), lemongrass, oleum and thyme, on X. axonopodis pv. vesicatoria (PHYX14) for controlling bacterial spot disease in tomato plants. The tested three essential oils (EOs) showed antibacterial activity in vitro test at 1:10 concentration against the PHYX14.Thyme oil exhibited the highest inhibition against PHYX14 followed by lemongrass and finally oleum. Under greenhouse conditions, the effect of EOs on the bacterial spot of tomato was evaluated on tomato seedlings. Thyme oil exhibited the highest reducing of tomato bacterial spot followed oleum and then lemongrass. Results indicated that the application of the tested (EOs) to tomato plants two days after the infection caused the highest reduction of disease severity. While the application of oleum oil exhibited the highest induction of the oxidative enzymes, peroxidase (PO) and polyphenol enzyme (PPO). Also increased total phenolic contents of tomato leaves followed lemongrass and then thyme oil as compared by control. The application of EOs two days before the infection caused the highest induction of PO, PPO enzymes and total phenolic contents in tomato leaves than two days after the inoculation.
Botrytis cinerea is the most widely studied necrotrophic phytopathogenic fungus. It causes economic losses that are difficult to calculate due to the large number of hosts. While there are a wide array of fungicides on the market to control this phytopathogen, they are not considered sustainable in terms of the environment and human health. The search for new alternatives to control this phytopathogen has led to the use of endophytic microorganisms as biological control agents. Endophytic bacteria and endophytic fungi have been isolated from different plant species and some have proven effective in inhibiting B. cinerea. Furthermore, a significant number of fungistatic or fungicidal metabolites which could be used as alternative complementary chemical controls have been isolated from these fungi and bacteria. In this review, in addition to the metabolites which have shown fungicide activity against this phytopathogen, the different genera and species of endophytic bacteria and fungi are also considered. These have been isolated from various plant species and have displayed antagonistic activity against B. cinerea.
This study aimed to investigate the mycoparasitism of Botrytis cinerea, the pathogen of scape and umbel blights of onion seed crops, by endophytic Talaromyces pinophilus. The dual culture test showed that the antagonistic potentiality of T. pinophilus against B. cinerea depend on the mycoparasitism that was morphologically detected by the formation of mycelial overgrowth. Moreover, the light micrograph of the mycelia at the contact zone exhibited that the hyphae of T. pinophilus penetrated and grew intracellularly inside the hyphae of B. cinerea. A more illustrative figure of the establishment of coiled hyphae as well as the conformation of the penetration process was assayed by SEM and TEM analyses. SEM micrograph revealed that the hyphae of T. pinophilus grew along hyphae of B. cinerea, attached, coiled around the host hypha and generated pseudoappressorium. A clear disintegration of cell wall of the host hypha was observed at the penetration site. The micrographs of TEM exhibited the ability of T. pinophilus to produce pseudoappressorium, penetrate and then entere a hypha of B. cinerea causing distinct cytoplasmic disorganization. High activities of cell wall degrading enzymes (chitinase, lipase and protease) involved in the mycoparasitism were evaluated by the endophytic T. pinophilus. In conclusion, this study demonstrated that the endophytic T. pinophilus may be a promising biocontrol agent against phytopathogenic fungi instead of chemical fungicides.
Guava (Psidium guajava Linn.) an important fruit of subtropical countries is affected by about 177 pathogens of which, 167 are fungal, 3 bacterial, 3 algal, 3 nematodes and one epiphyte. Wilt is the most important disease of guava. Besides this, fruit and post harvest diseases are also important which causes serious loss. The fruit diseases are of two types i.e. field diseases and post harvest diseases, which develop during transit and storage. Due to it's perishable nature number of pathogens are reported on fruits which causes different types of rots of guava fruits. In the present communication all major diseases are described with their symptoms, causal organisms and disease management practices.
Postharvest diseases cause considerable losses to harvested fruits and vegetables during transportation and storage. The aim of this study was to evaluate the antifungal potential of Thymus danensis and Thymus carmanicus against four postharvest pathogenic fungi (Rhizopus stolonifer, Penicillium digitatum, Aspergillus niger and Botrytis cinerea) which can reduce the shelf life of strawberry fruit. The chemical composition of plant oils was determined by capillary gas chromatography and mass spectrometry. Antifungal assays were carried out in vitro using PDA plates. Antifungal potential was found for 2 analysed essential oils. T. carmanicus oils have chemical compositions characterized by carvacrol (70%), p-cymene (12.4%) and γ-terpinene (2.5%) as the major components while the major constituents of the T. danensis were thymol (64.8%), α-terpinene (11.3%) and p-cymene (7.9%). Thymus sp. oils showed inhibitory effect even at low concentration (300 μl/L) against B. cinerea and R. stolonifer and showed inhibitory effect against A. niger and P. digitatum at 600 μl/L. Both essential oils tested in vivo at the preliminary concentration exhibited inhibitory activity against the four pathogens.
The essential oils of the aerial parts of Thymus schimperi growing in two different localities of Ethiopia were analysed using GC, GC-MS, 1H- and 13C-NMR data. T. schimperi oil from plant material collected in Dinshu (Bale Province) was found to contain thymol (50%), γ-terpinene (12.1%), carvacrol (10.1%) and p-cymene (10.0%) as the major constituents whereas carvacrol (66.2%) and γ-terpinene (13.2%) were shown to dominate in the same species obtained from Addis Ababa. Thymol (48.6%) and γ-terpinene (19.8%) were the major constituents of T. vulgaris oil acclimatized in Wondo Genet, Ethiopia.
Nine isolates of Trichoderma were collected from Assiut Governorate, Egypt, as leaf surface and endophytic fungi associated with onion flora stalks. Four isolates were identified as Trichoderma harzianum, while five isolates were belonging to Trichoderma longibrachiatum. The antagonistic activity of these isolates against onion purple blotch pathogen Alternaria porri was studied in vitro using dual culture assay. All tested Trichoderma isolates showed mycoparasitic activity and competitive capability against the mycelial growth of A. porri. Mycoparastic activity of Trichoderma was manifested morphologically by the overgrowth upon the mycelial growth of the pathogen and microscopically by production of coiling hyphae around pathogen hyphae. Isolates of T. harzianum exhibited high ability to compete on potato dextrose agar (PDA) medium causing the maximum rate of pathogen inhibition (73.12%), while isolates of T. longibrachiatum showed inhibition rate equalling 70.3%. Chitinase activity of Trichoderma was assayed, and T. harzianum Th-3013 showed the maximum value con-tributing 2.69 U/min. Application of T. harzianum Th-3013 to control pur-ple blotch disease in vivo under greenhouse conditions caused disease reduction up to 52.3 and 79.9% before and after 48 h of pathogen inocu-lation, respectively, while the fungicide Ridomil Gold Plus caused disease reduction comprising 56.5 and 71.7%, respectively. This study proved that T. harzianum Th-3013 as a biocontrol agent showed significant reduction in onion purple blotch disease compared with the tested fungicide.
In the continual search by both pharmaceutical and agricultural industries for new products, natural selection has been found to be superior to combinatorial chemistry for discovering novel substances that have the potential to be developed into new industrial products. Since natural products are adapted to a specific function in nature, the search for novel secondary metabolites should concentrate on organisms that inhabit novel biotopes. Endophytic fungi inhabit such a biotope. In the course of the last 12 years, we have isolated ~ 6500 endophytic fungi from herbaceous plants and trees, screened them for biological activities, and have isolated and determined the structures of the biologically active compounds. Correlations were found between biological activity and biotope, e.g. a higher proportion of the fungal endophytes, in contrast to the soil isolates, inhibited at least one of the test organisms for antialgal and herbicidal activities. The substances isolated originated from different biosynthetic pathways: isoprenoid, polyketide, amino acid derivatives, and belonged to diverse structural groups: terpenoids, steroids, xanthones, chinones, phenols, isocumarines, benzopyranones, tetralones, cytochalasines, and enniatines. The potential role of the endophyte and its biologically active metabolites in its association with its host has been investigated. The fungal endophytes possess the exoenzymes necessary to colonize their hosts and they grow well in the apoplastic washing fluid of the host. When the roots of larch are colonized, the association with the host may be mutualistic, improving growth of the host and supplying the mycobiont with enough nourishment to extensively colonize the host's roots. The concentrations of some plant defence metabolites are lower than in the control when the host is infected with a pathogen than with an endophyte. We hypothesize that the interaction fungal endophyte-plant host is characterized by a finely tuned equilibrium between fungal virulence and plant defence. If this balance is disturbed by either a decrease in plant defence or an increase in fungal virulence, disease develops. Not only must the endophyte synthesize metabolites to compete first with epiphytes and then with pathogens in order to colonize the host, but presumably also to regulate metabolism of the host in their delicately balanced association. The utilization of a biotope such as that of the fungal endophyte is one aspect of intelligent screening, another very important one is the taxonomy of the fungus in order to avoid redundant structural isolations. It is not a random walk through a random forest. Many groups of fungi in different biotopes are waiting to be exploited.
The essential oil and various extracts obtained from Salvia cedronella Boiss have been evaluated for their possible in vitro antimicrobial and antiviral capacities. The GC-EIMS analysis of the essential oil was resulted in detection of 92 components representing 96.1% of the oil. Major components were 1,8- cineole, α α α α-pinene, caryophyllene oxide and sabinene. In the case of antimicrobial activity, hexane and dichloromethane extracts did not show any effects. Methanolic extract and essential oil exhibited various degrees of activity against the tested microorganisms. The antiviral potential of the plant samples was screened in 2 model systems namely; reproduction of 2 influenza viruses in MDCK cells and of 2 herpes simplex viruses in MDBK cells. The methanol extract showed a good anti-influenza virus effect, the growth of both A/Weybridge and A/Aichi was reduced significantly. This extract also exhibited anti-herpetic activity. Amount of the total phenolics was very high in methanol extract. It was followed by dichloromethane. This extract has also been found to be rich in flavonoids. A positive correlation was observed between biological activity potential and amount of phenolic compounds of the extracts.
W.H. (1999). Single spore isolation of fungi. Fungal Diversity 3: 29-38. Methods to isolate fungi from single spores are outlined. These methods are specifically designed for mycological laboratories which are not necessarily well funded. Therefore, they involve a simple procedure, are relatively inexpensive, and most importantly effective. Furthermore, only basic equipment is required. By using these methods, most fungi, with the exception of those that do not germinate on artificial medium, can be isolated. Some approaches are suggested to prevent mite infestations and to reduce the risk of bacterial contamination.
Borytis cinerea is responsible for the most postharvest losses of table grape. In the current research, the effect of essential oils extracted from sweet basil, fennel, summer savory and thyme plants were investigated both on mycelial growth of B. cinerea under in vitro condition and on fungal decay and quality sensors of table grape [Vitis vinifera (L.) cv. Tabarzeh] under in vivo conditions. Results showed that essential oils especially thyme, fennel and summer savory oils had a high inhibitory effect on mycelial growth of B. cinerea. Under in vivo assays, thyme and summer savory oils were able to reduce fungal decay sensory on table grape after 60 days of storage. In addition, essential oils had significant efficacy on quality parameters of fruit reducing a weight loss, berry shrinkage and berry and rachis browning. Also essential oil treatment increased the maturity index levels in treated fruits in comparison with controls. GC/MS analysis showed that linalool (65.25%), trans-anethole (64.72%), carvacrol (54.14%) and β-ocimene (12.62%) were the main compounds identified in sweet basil, fennel, summer savory and thyme oils, respectively. Results obtained from presented study showed that essential oils especially these one containing more phenolic compounds had a great antifungal activity and could be used as a benefit and safe tool for preservation of table grape.
It was found that plant storage tissues (fleshy sugar-containing fruits, subsurface metamorphically altered plant organs (storage
roots, tubers, etc.), and starch-containing seed lobes) nearly always contain yeasts that are able to actively reproduce in
these tissues causing no visible damage. Within storage tissues, yeast cells were detected both in the intercellular space
and inside plant cells. In the tissues of fleshy fruits, endophytic yeasts are represented by the same species as epiphytic
ones; cryptococci of the order Filobasidiales and ascomycetes belonging to the genera Hanseniaspora and Metschnikowia are predominant. In subsurface plant organs, red pigmented basidiomycetous yeasts of the genus Rhodotorula prevail. Selective growth of representatives of one species, Candida railenensis, is typical of starch-containing storage tissues of seeds. The results obtained change the established notion of the distributional
patterns of yeast fungi in natural habitats and suggest that internal storage tissues of plants can be considered as a new
interesting model for studies of coevolving plant-microbial associations.
Fifty-one endophytic isolates of Aureobasidium pullulans were obtained from the flesh of sweet cherries and extensively screened to evaluate their biocontrol activity against postharvest rots of sweet cherries and table grapes. Preliminary analysis of all isolates by randomly amplified polymorphic DNA (RAPD) with three different primers showed the presence of a high genetic variability and enabled isolates not showing any genetic difference to be discarded. Thirty-five isolates with different RAPD electrophoresis patterns had a wide range of biocontrol activity against Botrytis cinerea and Monilinia laxa on single-wounded berries of sweet cherries and table grapes with a reduction of decay from 10 to 100%. Two isolates (533 and 547) significantly reduced B. cinerea on table grape berries also when applied 6, 12, and 24 h after the pathogen inoculation. In a 2-year period of investigation (1998–1999), a reduction of total rots ranging from 32 to 80% (sweet cherries) and from 59 to 64% (table grape) was achieved with isolates 533 and 547 applied after harvest. Preharvest applications of isolate 547 significantly reduced postharvest rots of sweet cherries and table grapes by 47 and 38%, respectively. On the whole, isolates 533 and 547 were more effective than A. pullulans L47, a biocontrol agent of postharvest diseases with a known activity. Population studies demonstrated that isolate 547 was able to survive under field conditions, to increase its population during cold storage, and to penetrate the flesh of sweet cherries when applied during flowering.
The complete nucleotide sequence of the glucoamylase gene GLU1 from the yeast Saccharomycopsis fibuligera has been determined. The GLU1 DNA hybridized to a polyadenylated RNA of 2.1 kilobases. A single open reading frame codes for a 519-amino-acid protein which contains four potential N-glycosylation sites. The putative precursor begins with a hydrophobic segment that presumably acts as a signal sequence for secretion. Glucoamylase was purified from a culture fluid of the yeast Saccharomyces cerevisiae which had been transformed with a plasmid carrying GLU1. The molecular weight of the protein was 57,000 by both gel filtration and acrylamide gel electrophoresis. The protein was glycosylated with asparagine-linked glycosides whose molecular weight was 2,000. The amino-terminal sequence of the protein began from the 28th amino acid residue from the first methionine of the putative precursor. The amino acid composition of the purified protein matched the predicted amino acid composition. These results confirmed that GLU1 encodes glucoamylase. A comparison of the amino acid sequence of glucoamylases from several fungi and yeast shows five highly conserved regions. One homology region is absent from the yeast enzyme and so may not be essential to glucoamylase function.
Losses from postharvest fruit diseases range from 1 to 20 percent in the United States, depending on the commodity. The application of fungicides to fruits after harvest to reduce decay has been increasingly curtailed by the development of pathogen resistance to many key fungicides, the lack of replacement fungicides, negative public perception regarding the safety of pesticides and consequent restrictions on fungicide use. Biological control of postharvest diseases (BCPD) has emerged as an effective alternative. Because wound-invading necrotrophic pathogens are vulnerable to biocontrol, antagonists can be applied directly to the targeted area (fruit wounds), and a single application using existing delivery systems (drenches, line sprayers, on-line dips) can significantly reduce fruit decays. The pioneering biocontrol products BioSave and Aspire were registered by EPA in 1995 for control of postharvest rots of pome and citrus fruit, respectively, and are commercially available. The limitations of these biocontrol products can be addressed by enhancing biocontrol through manipulation of the environment, using mixtures of beneficial organisms, physiological and genetic enhancement of the biocontrol mechanisms, manipulation of formulations, and integration of biocontrol with other alternative methods that alone do not provide adequate protection but in combination with biocontrol provide additive or synergistic effects.
DNA coding for a secretable acid protease gene of Saccharomycopsis fibuligera was isolated from a genomic DNA library of the organism. Saccharomyces cerevisiae cells transformed with aplasmid carrying the cloned gene secreted protease having the same enzymatic properties as those ofthe S. fibuligera protease. Southern blot analysis of genomic DNA from S. fibuligera confirmed thatthe protease gene was derived from S. fibuligera.
Arthroascus fermentans, a new arthrosporous, fermenting, ascogenous yeast species, is described. The three strains of the species included in this study were isolated from soil samples obtained from different orchards in Taiwan. The species is homothallic, and the major ubiquinone isoprenolog is Q-8. DNA hybridization and DNA base composition data indicate that A. fermentans is a species that is distinct from previously described Arthroascus species. The type strain of A. fermentans is strain 80D2303, which has been deposited in the Culture Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, Taiwan, as strain CCRC 22530.
A number of Saccharomycopsis fibuligera strains that can hydrolyse and utilize starch as a carbon source were isolated from nuruk, a traditional Korean starter for rice wine fermentation, and their specific growth rates on starch-containing medium were compared to choose the prominent strain. S. fibuligera strain MBY1320 showed a higher growth rate at 42°C than that of strain S fibuligera KCTC7806, indicating that S. fibuligera MBY1320 has more thermo-tolerant machinery for starch hydrolysis and utilization than KCTC7806 Although the activity of a-amylase at 30°C was significantly lower for S fibuligera MBY1320 than KCTC7806 (3,812.5 U vs. 14,878.5 U), S fibuligera MBY1320 showed a much higher glucoamylase activity at 42°C than S. fibuligera KCTC7806 (5,048.9 U vs 13,152 3 U). Thus, a new S. fibuligera strain, with a higher starch-hydrolysing activity at elevated temperatures than that of other types of strain, this study reports.
Chemical fungicides have been intensively used in the control of postharvest decay in fruit in postharvest conditions; nevertheless, continuous use of these fungicides has faced two major obstacles: development of pathogen resistance to many key fungicides, and public knowledge on the health and environmental hazards of these compounds. This study evaluated the efficacy of Lactobacillus plantarum A7, thyme (Thymus vulgaris L.) and cumin (Cuminum cyminum L.) essential oils and the combination of these three elements as postharvest biocontrol agents against Botrytis spp. on strawberry fruit. Thyme oil had a remarkable antifungal effect against Botrytis spp. in vitro, whereas an inhibitory effect of cumin oil was achieved in higher concentrations. With thyme oil (2 h after artificial inoculation of the fruit), among three tested concentrations, only the 200 μL/L concentration showed an inhibitory effect on strawberries against Botrytis spp. (91.97%), while higher concentrations of cumin oil were required to prevent decay significantly. Both combinations of L. plantarum+ cumin oil and L. plantarum+ thyme oil completely inhibited the mycelia growth of the pathogens in vitro. Results showed that the combined treatments of strawberry fruit with L. plantarum+ cumin oil (50 μL/L) and L. plantarum+ thyme oil (100 μL/L) resulted in remarkably improved control of Botrytis infections, in comparison to the stand-alone application of L. plantarum A7 or essential oils. Quality (i.e. pH, acidity and ascorbic acid content) and sensory attributes of the strawberry fruit were better in the case of using cumin compared to thyme oil, when a combination of L. plantarum A7 and essential oils was used. This study has demonstrated that the integration of L. plantarum A7 with thyme and cumin essential oils is a potential biocontrol tool as a biofungicide in postharvest stage.
The essential oils from two clonal types of Thymus vulgaris (Laval-1 and Laval-2) were characterized and tested for antifungal activity. Contents were high in p-cymene, linalool, terpinen-4-ol and thymol which constituted 53.5% and 66.2% of Laval-1 and Laval-2 essential oils respectively. The essential oil volatiles from two clonal types exhibited antifungal activity against Botrytis cinerea and Rhizopus stolonifer, two common storage pathogens of strawberries (Fragaria ananassa). The inhibition of B. cinerea and R. stolonifer ranged from 26.5 to 63.5% and 5.5 to 50.5% respectively by oil from Laval-1, when exposed to concentrations of 50 to 200 ppm, while values of 36.9 to 90.5% and 11.5 to 65.8% were observed from oil from Laval-2. The decay of strawberry fruits caused by B. cinerea and R. stolonifer was controlled up to 73.6 and 73.0% respectively by volatiles from maximin concentration of Laval-1, and up to 75.8 and 74.8% from Laval-2. No visual phytotoxic symptoms were noticed for the observed period. Essential oil from Laval-2 exhibited higher antifungal activity which was related to its relatively higher content of antimicrobial compounds.
Post-harvest physico-chemical treatments—water at 40 °C or 60 °C (HW), and sodium bicarbonate at 1 or 2.5% (SBC) at 20, 40 and 60 °C—were tested on peaches and nectarines in order to control brown rot caused by Monilinia spp. and to select the best physico-chemical treatment to be used in combination with pre-harvest applications of the biological control agent Epicoccum nigrum (ATCC number 96794). Experiments were carried out in France, Italy and Spain in order to test different experimental conditions. Monilinia rot was reduced in peach and nectarine treated with HW (40 °C for 2 min) in all three countries, the percentage of rot reduction was similar for France, Italy and Spain (over 40%). A synergistic effect between HW at 40 °C during 150 s or at 60 °C during 20 s and SBC was observed in all three countries. After preliminary experiments post-harvest treatment of HW (60 °C) + SBC (1%) during 20 s was selected to combine it with field treatments. Pre-harvest treatments with fungicide or E. nigrum did not reduce brown rot in any country. However, pre-harvest treatments with E. nigrum, chemical fungicide, and their integration followed by post-harvest physico-chemical treatment significantly reduced Monilinia rot compared to pre-harvest untreated fruits followed by post-harvest physico-chemical treatment in Italy (over 70%). Post-harvest treatments with E. nigrum were also tested in Italy on natural and artificial infections in nectarine over 3 years. E. nigrum, as fresh or formulated cells, at a concentration of 108 conidia mL−1 were effective, significantly reducing the incidence of brown rot compared to control, both under artificial and natural infection, from 43 to 100%. Copyright © 2007 Society of Chemical Industry
Penconazole is a systemic triazole fungicide mainly used on grapes. The UE Maximum Residue Level (MRL) for penconazole is set at 0.2 ppm in wine and grapes. In the aim of identifying potential biomarkers of exposure to penconazole and possibly highlighting its endocrine disrupting mode of action, we used a transcriptomics-based approach to detect genes, that are transcriptionally modulated by penconazole, by using an appropriate in vitro model. T-47D cells were treated with commercial penconazole or penconazole contaminated grape extracts for 4 hours at doses close to the MRL. The whole-genome transcriptomic profile was assessed by using genome 44 K oligo-microarray slides. The list of common genes generated by the two treatments could be representative of potential markers of exposure. In order to understand the role of these genes in key events related to adversity, a pathway analysis was performed on a list of genes with the same modulation trend (up or down). The analysis returned a set of genes involved in Thyroid Cancer Pathway, thus confirming a role of penconazole in endocrine disrupting mediated effects and strongly suggesting a possible mode of action in thyroid carcinogenesis.
A DNA fragment containing the gene coding for extracellular glucoamylase ofSaccharomycopsis fibuligera was isolated from a genomic DNA library of the organism.Saccharomyces cerevisiae cells transformed with a plasmid carrying the cloned gene secreted glucoamylase having the same enzymatic properties as those ofS. fibuligera glucoamylase, and fermented starch. Southern blot analysis of genomic DNA fromS. fibuligera confirmed that the glucoamylase gene was derived fromS. fibuligera.
Post-harvest physico-chemical treatments—water at 40 °C or 60 °C (HW), and sodium bicarbonate at 1 or 2.5% (SBC) at 20, 40 and 60 °C—were tested on peaches and nectarines in order to control brown rot caused by Monilinia spp. and to select the best physico-chemical treatment to be used in combination with pre-harvest applications of the biological control agent Epicoccum nigrum (ATCC number 96794). Experiments were carried out in France, Italy and Spain in order to test different experimental conditions. Monilinia rot was reduced in peach and nectarine treated with HW (40 °C for 2 min) in all three countries, the percentage of rot reduction was similar for France, Italy and Spain (over 40%). A synergistic effect between HW at 40 °C during 150 s or at 60 °C during 20 s and SBC was observed in all three countries. After preliminary experiments post-harvest treatment of HW (60 °C) + SBC (1%) during 20 s was selected to combine it with field treatments. Pre-harvest treatments with fungicide or E. nigrum did not reduce brown rot in any country. However, pre-harvest treatments with E. nigrum, chemical fungicide, and their integration followed by post-harvest physico-chemical treatment significantly reduced Monilinia rot compared to pre-harvest untreated fruits followed by post-harvest physico-chemical treatment in Italy (over 70%). Post-harvest treatments with E. nigrum were also tested in Italy on natural and artificial infections in nectarine over 3 years. E. nigrum, as fresh or formulated cells, at a concentration of 108 conidia mL−1 were effective, significantly reducing the incidence of brown rot compared to control, both under artificial and natural infection, from 43 to 100%. Copyright © 2007 Society of Chemical Industry
We have designed two taxon-selective primers for the internal transcribed spacer (ITS) region in the nuclear ribosomal repeat unit. These primers, ITS1-F and ITS4-B, were intended to be specific to fungi and basidiomycetes, respectively. We have tested the specificity of these primers against 13 species of ascomycetes, 14 of basidiomycetes, and 15 of plants. Our results showed that ITS4-B, when paired with either a ‘universal’ primer ITS1 or the fungal-specific primer ITS1-F, efficiently amplified DNA from all basidiomycetes and discriminated against ascomycete DNAs. The results with plants were not as clearcut. The ITS1-F/ITS4-B primer pair produced a small amount of PCR product for certain plant species, but the quantity was in most cases less than that produced by the ‘universal’ ITS primers. However, under conditions where both plant and fungal DNAs were present, the fungal DNA was amplified to the apparent exclusion of plant DNA. ITS1-F/ITS4-B preferential amplification was shown to be particularly useful for detection and analysis of the basidiomycete component in ectomycorrhizae and in rust-infected tissues. These primers can be used to study the structure of ectomycorrhizal communities or the distribution of rusts on alternate hosts.
The antifungal potential of essential oils of oregano (Origanum vulgare), thyme (Thymus vulgaris) and clove (Syzygium aromaticum) was determined. To establish this antifungal potential, two molds related to food spoilage, Aspergillus niger and Aspergillus flavus, were selected. The agar dilution method was employed for the determination of antifungal activities. The three essential oils analyzed presented inhibitory effects on both molds tested. Oregano essential oil showed the highest inhibition of mold growth, followed by clove and thyme. Aspergillus flavus was more sensitive to thyme essential oil than A. niger. Clove essential oil was a stronger inhibitor against A. niger than against A. flavus.
Guava (Psidium guajava Linn.) an important fruit of subtropical countries is affected by about 177 pathogens of which, 167 are fungal, 3 bacterial,
3 algal, 3 nematodes and one epiphyte. Wilt is the most important disease of guava. Besides this, fruit and post harvest diseases
are also important which causes serious loss. The fruit diseases are of two types i.e. field diseases and post harvest diseases, which develop during transit and storage. Due to it’s perishable nature number
of pathogens are reported on fruits which causes different types of rots of guava fruits. In the present communication all
major diseases are described with their symptoms, causal organisms and disease management practices.
Data on chemical composition related to the synthesis of physiologically active substances (alkaloids, terpenoids, glycosides, phenolic compounds, etc.) and to the accumulation of individual elements or groups of five to ten elements (e.g., Cr, Co, Mn, and Zn) in medicinal plants were reviewed. Chemical features of medicinal plants serve as an integral determinant of their species specificity and pharmacological properties and enable their wide use in medical practice. The relationship between the synthesis of physiologically active substances and accumulation of elements is mediated by several levels of molecular regulation.
A total of 14 odoriferous angiospermic essential oils were tested against the toxigenic strain of Aspergillus flavus. The essential oil of Thymus vulgaris L. showed highest antifungal efficacy. The thyme oil absolutely inhibited the mycelial growth of A. flavus at 0.7 μl ml− 1 and exhibited a broad fungitoxic spectrum against eight different food contaminating fungi viz. Fusarium oxysporum, Cladosporium herbarum, Curvularia lunata, Aspergillus terreus, Aspergillus niger, Aspergillus fumigatus, Alternaria alternata and Botryodiploidia theobromae. The oil also showed significant antiaflatoxigenic efficacy as it completely arrested the aflatoxin B1 production at 0.6 μl ml− 1. Thyme oil as fungitoxicant was also found superior over most of the prevalent synthetic fungicides. The LC50 of thyme oil against mice was recorded as 7142.85 μl kg− 1 body weight indicating its non-mammalian toxicity and strengthening its safe exploitation as preservative for stored food commodities. The findings recommend the thyme oil as potential botanical preservative in eco-friendly control of biodeterioration of food commodities during storage.Industrial relevanceThe thyme essential oil may be recommended for large scale application as a plant based preservative for stored food items because of its strong antifungal as well as antiaflatoxigenic efficacy. Because of broad antimicrobial spectrum, more efficacy over prevalent synthetic preservatives as well as non-mammalian toxicity, the thyme essential oil may be formulated as a safe and economical plant based preservative against post harvest fungal infestation and aflatoxin contamination of food commodities.
Gray mold, caused by Botrytis cinerea, is the most important postharvest disease of table grapes. Chitosan, a natural biopolymer with antifungal and eliciting properties, and ethanol, a common food additive with antifungal properties, are both able to reduce postharvest decay of table grapes. The effectiveness of reduced doses of chitosan and ethanol, applied alone or in combination, to control gray mold of table grapes was evaluated. Artificially inoculated single berries or clusters were immersed in chitosan (0.1 and 0.5%), ethanol (10 and 20%), or their mixture. The combination of 0.5% chitosan with 10 or 20% ethanol improved decay control with respect to their single treatments, while combinations of 0.1% chitosan with 10 or 20% ethanol did not improve gray mold control compared to the treatments applied alone. On single berries stored 7 days at 15 ± 1 °C, the highest levels of decay control were observed on grapes treated with the combination of 0.5% chitosan and 10 or 20% ethanol (reductions of 94 and 97% on cv Autumn Seedless and 69 and 73% on Thompson Seedless, respectively, compared to controls). On small clusters stored 60 days at 0.5 ± 1 °C, the highest percent reduction was observed on grapes treated with the combination of 0.5% chitosan and 10 or 20% ethanol (reductions of 47 and 60% in Thompson Seedless, and 70 and 94% in Autumn Seedless, respectively, compared to controls). The tests with small clusters were carried out to simulate commercial prolonged cold storage of table grapes. The combination of reduced doses of chitosan and ethanol improved the control of gray mold of table grapes compared to their application alone, and the effect was at least additive and at times synergistic.
Bacillus amyloliquefaciens PPCB004 was selected as a potential antagonist to control Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer on peach fruit. The HPLC data of PPCB004 indicated the lipopeptides iturin A, fengycin and surfactin as secondary metabolites. The GC/MS analysis of PPCB004 showed 3-hydroxy-2-butanone as the dominant compound (97.52% of relative peak area). Thyme (TO) and lemongrass (LO) oils showed over 50% and 25% inhibition of radial mycelial growth respectively with 8 μl oil per plate for all pathogens. Combination treatment with both oils failed to increase the percentage inhibition of radial mycelial growth of the pathogens. Combined application of PPCB004 with TO or LO was tested to assess the effectiveness in the control of these pathogens during postharvest storage. The biofilm formation of PPCB004 was significantly higher in LO than TO. LO (6 μl plate−1) and PPCB004 completely inhibited the mycelial growth of the pathogens. Fruit inoculation trials with PPCB004 + LO in NatureFlex™ modified atmosphere packaging (MAP), showed lower disease incidence and severity at 25 °C for 5 d than treatments with PPCB004 + MAP, PPCB004 + TO + MAP, LO + MAP, TO + MAP or stand-alone MAP. On naturally infected fruit, PPCB004 + LO + MAP and LO + MAP treatments retained the total soluble solids/titratable acidity ratio and flesh firmness but failed to stimulate the levels of total phenolic content, phenylalanine ammonia-lyase, β-1,3-glucanase and chitinase activities. Combination of PPCB004 (spray treatment) + LO (in pad delivery system) in NatureFlex™ MAP showed absence of disease and off-flavour development, retained the overall appearance and increased the overall acceptance at market shelf conditions (20 °C for 2 d) after cold storage at 4 °C for 14 d.
Postharvest diseases cause considerable losses to harvested fruits and vegetables during transportation and storage. Synthetic fungicides are primarily used to control postharvest decay loss. However, the recent trend is shifting toward safer and more eco-friendly alternatives for the control of postharvest decays. Of various biological approaches, the use of antagonistic microorganisms is becoming popular throughout the world. Several postharvest diseases can now be controlled by microbial antagonists. Although the mechanism(s) by which microbial antagonists suppress the postharvest diseases is still unknown, competition for nutrients and space is most widely accepted mechanism of their action. In addition, production of antibiotics, direct parasitism, and possibly induced resistance in the harvested commodity are other modes of their actions by which they suppress the activity of postharvest pathogens in fruits and vegetables. Microbial antagonists are applied either before or after harvest, but postharvest applications are more effective than preharvest applications. Mixed cultures of the microbial antagonists appear to provide better control of postharvest diseases over individual cultures or strains. Similarly, the efficacy of the microbial antagonist(s) can be enhanced if they are used with low doses of fungicides, salt additives, and physical treatments like hot water dips, irradiation with ultraviolet light etc. At the international level, different microbial antagonists like Debaryomyces hansenii Lodder & Krejer-van Rij, Cryptococcus laurentii Kufferath & Skinner, Bacillus subtilis (Ehrenberg) Cohn, and Trichoderma harzianum Rifai, are being used. Biocontrol products like Aspire, BioSave, and Shemer etc., have also been developed and registered. Although the results of this technology are encouraging, we need to continue to explore potential uses on the commercial scale in different corners of the world.
The use of biocontrol agents as an alternative to synthetic, chemical fungicides that are presently used to control postharvest pathogens, has many constraints and obstacles that make it difficult to implement their use as a practical control strategy. Over the last 20 years postharvest biocontrol research has evolved towards being more integrated into a production systems approach with greater awareness of industry concerns. More research, however, is needed in many aspects of the science and technology of postharvest biocontrol and in integrating biocontrol agents into combined pre- and postharvest production and handling systems. Better understanding of the mode of action of postharvest biocontrol agents, relationships between infection levels occurring in the field and development of postharvest decay, along with basic information on microbial ecology and survival mechanisms of biocontrol agents on fruit surfaces, is critical for the advancement of successful implementation of postharvest biocontrol technology. The past 20 years of postharvest biocontrol research has seen tremendous advances and the creation of several products. Nonetheless, numerous challenges and opportunities still exist as this field of research matures. This review is an attempt to examine the field of postharvest biocontrol as it has developed over the past 20 years, define the reasons that have limited its commercialization, and identify areas of research that need to be addressed if the potential of postharvest biocontrol is to be achieved. We have also introduced a new paradigm for biocontrol research that may provide new opportunities for increasing the efficacy and consistency of biocontrol products.
The chemical composition and antimicrobial properties of the essential oils of three common Australian Eucalyptus species, namely E. olida, E. staigeriana and E. dives were determined by gas chromatography/mass spectrometry and the agar disc diffusion method, respectively. A total of 24 compounds were identified from the essential oil of E. dives, with the dominant compounds being piperitone (40.5%), α-phellandrene (17.4%), p-cymene (8.5%) and terpin-4-ol (4.7%). For E. staigeriana, 29 compounds were identified with 1,8-cineole (34.8%), neral (10.8%), geranial (10.8%), α-phellandrene (8.8%) and methyl geranate (5.2%) being the dominant ones. In contrast, a single compound, (E)-methyl cinnamate, accounted for 99.4% of the essential oils of E. oilda, although 20 compounds were identified. The essential oils displayed a variable degree of antimicrobial activity with E. staigeriana oil showing the highest activity. In general, Gram-positive bacteria were found to be more sensitive to the essential oils than Gram-negative bacteria. Staphylococcus aureus was the most sensitive strain while Pseudomonas aeruginosa was the most resistant.
Constructs carrying the Saccharomycopsis fibuligera β-glucosidase gene (BGL1) under the control of a constitutive actin or a galactose-inducible promoter were introduced into eleven Saccharomyces strains. In ten of these recombinant strains, BGL1 expression driven by the actin promoter was between 1.6- and 18-fold higher than that obtained with the galactose-inducible promoter. Strains carrying the actin promoter yielded ethanol concentrations from cellobiose of between 0.5% and 14%, depending on their ability to accumulate Bgl1 (between 30 and 250 mU/mL) but also on their genetic background. Comparative analysis of a S. cerevisiae strain and its corresponding petite version showed similar ethanol yields, despite a 3-fold lower β-glucosidase production of the latter, suggesting that respiratory activity could be one of the factors influencing ethanol production when using carbon sources other than glucose. This study provides a selection of strains that may be good candidates as hosts for ethanol biosynthesis from cellulosic substrates.
Introduction:
Botrytis cinerea (teleomorph: Botryotinia fuckeliana) is an airborne plant pathogen with a necrotrophic lifestyle attacking over 200 crop hosts worldwide. Although there are fungicides for its control, many classes of fungicides have failed due to its genetic plasticity. It has become an important model for molecular study of necrotrophic fungi.
Taxonomy:
Kingdom: Fungi, phylum: Ascomycota, subphylum: Pezizomycotina, class: Leotiomycetes, order: Helotiales, family: Sclerotiniaceae, genus: Botryotinia.
Host range and symptoms:
Over 200 mainly dicotyledonous plant species, including important protein, oil, fibre and horticultural crops, are affected in temperate and subtropical regions. It can cause soft rotting of all aerial plant parts, and rotting of vegetables, fruits and flowers post-harvest to produce prolific grey conidiophores and (macro)conidia typical of the disease.
Pathogenicity:
B. cinerea produces a range of cell-wall-degrading enzymes, toxins and other low-molecular-weight compounds such as oxalic acid. New evidence suggests that the pathogen triggers the host to induce programmed cell death as an attack strategy. Resistance: There are few examples of robust genetic host resistance, but recent work has identified quantitative trait loci in tomato that offer new approaches for stable polygenic resistance in future.
Useful websites:
http://www.phi-base.org/query.php, http://www.broad.mit.edu/annotation/genome/botrytis_cinerea/Home.html, http://urgi.versailles.inra.fr/projects/Botrytis/, http://cogeme.ex.ac.uk.
The circumscription of mycelial genera among the ascomycetous yeasts has been controversial because of widely different interpretations of the taxonomic significance of their phenotypic characters. Relationships among species assigned to mycelial genera were determined from extent of divergence in a ca. 600-nucleotide region near the 5′ end of the large subunit (26S) ribosomal DNA gene. Phylogenetic analyses showed that Stephanoascus is distinct from Zygoascus and that Blastobotrys, Sympodiomyces, and Arxula represent anamorphs of the Stephanoascus clade. The analyses demonstrated the following teleomorphic taxa to be congeneric: Ambrosiozyma/Hormoascus, Saccharomycopsis/Guilliermondella/Botryoascus/Arthroascus, Dipodascus/Galactomyces, and Eremothecium/Ashbya/Nematospora/Holleya. Species assigned to Dipodascus comprise two separate clades. New taxonomic combinations are proposed that reflect the phylogenetic relationships determined. Key words: mycelial yeasts, ribosomal rRNA/rDNA, molecular systematics.
Saccharomycopsis fibuligera is found to actively accumulate trehalose from starch and the gene responsible for biosynthesis of trehalose has been cloned and its expression has been characterized. This yeast is also found to secrete a large amount of amylases, acid protease and beta-glucosidase which have highly potential applications in fermentation industry. The genes encoding amylases, acid protease and beta-glucosidase in S. fibuligera have been cloned and characterized. It is also used to produce ethanol from starch, especially cassava starch by co-cultures of Saccharomyces cereviase or Zymomonas mobilis.
Botrytis cinerea has been found to be highly pathogenic to 'Chardonnay' and 'Pinot noir' cultivars of the grape-vine producing the characteristic grey mould symptoms within 7 days of inoculation to the vitro-plants. The yeast Pichia anomala (strain FY-102), isolated from apple skin, was found to be antagonistic to B. cinerea as it completely inhibited the appearance of the grey mould symptoms when grown together. The yeast was responsible for morphological changes such as coagulation and leakage of the cytoplasm of B. cinerea. The pathogen, when applied together with P. anomala, failed to bring about the grey mould symptoms on the grape-vine, suggesting that the yeast could control the expression of this disease. An account of the interaction between B. cinerea and P. anomala, as well as the sequences of the complete ITS region of the ribosomal DNA of the yeast are described here.
Vitamin C content in fresh and freeze-dried herbal juice, such as guava (Psidium guajava Linn.) emblic myrobolan (Phyllanthus embica Linn.), lemon (Citrus aurantifollia Swing), sweet pepper (Capsicum annuum Linn.) Garcinia schomburgkiana Pierre and passion fruit (Passiflora laurifoia Linn.) was determined by direct titration with iodine. The method showed excellent linearity (r2>0.99) over the concentration ranges tested (100-500% of the amount found in the juice samples), good precision (R.S.D.<1.5%) and recovery (>97%). The limit of detection and limit of quantitation were 2.2 and 7.3 mg, respectively. The amount of vitamin C found were 80.1 mg/100 g for guava, 226.0 mg/100 g for emblic myrobolan, 52.8 mg/100 g for sweet pepper, 39.1 mg/100 g for passion fruit, 10.5 mg/100 g for lemon and 4.6 mg/100 g for G. schomburgkiana. The stability of vitamin C during the first 4 weeks was remarkably improved after freeze-dried process. The percent reductions of vitamin C after freeze-dried process were 41.4 and 20.4% for guava and emblic myrobolan, respectively. After 8 weeks, the freeze-dried samples contained only traces amount of vitamin C tested by thin layer chromatography.
In recent years there has been an increasing interest in the use of natural substances, and some questions concerning the safety of synthetic compounds have encouraged more detailed studies of plant resources. Essential oils, odorous and volatile products of plant secondary metabolism, have a wide application in folk medicine, food flavouring and preservation as well as in fragrance industries. The antimicrobial properties of essential oils have been known for many centuries. In recent years (1987-2001), a large number of essential oils and their constituents have been investigated for their antimicrobial properties against some bacteria and fungi in more than 500 reports. This paper reviews the classical methods commonly used for the evaluation of essential oils antibacterial and antifungal activities. The agar diffusion method (paper disc and well) and the dilution method (agar and liquid broth) as well as turbidimetric and impedimetric monitoring of microorganism growth in the presence of tested essential oils are described. Factors influencing the in vitro antimicrobial activity of essential oils and the mechanisms of essential oils action on microorganisms are reported. This paper gives an overview on the susceptibility of human and food-borne bacteria and fungi towards different essential oils and their constituents. Essential oils of spices and herbs (thyme, origanum, mint, cinnamon, salvia and clove) were found to possess the strongest antimicrobial properties among many tested.