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Induction of PAL activity and dihydrostilbene phytoalexins in Dioscorea alata and their plant growth inhibitory properties
Abstract
Dihydropinosylvin, batatasin IV, demethylbatatasin IV and batatasin III were found in the water yam (Dioscorea alata) which had been inoculated with Botryodiplodia theobromae or treated with mercuric chloride. Following induction, transient increases were observed in the first three compounds and this was preceded by a transient increase in the activity of phenylalanine ammonia lyase but not tyrosine ammonia lyase activity. In mercuric chloride treated tubers an increase in polyphenol oxidase was also observed. The dormancy inducing compounds dihydropinosylvin and batatasin IV were also found to inhibit the germination of seeds of and root elongation in young seedlings of Sorghum bicolor. By comparison, demethylbatatasin IV was not inhibitory.
... The peel of D. rotundata (White yam, isu funfun) has been shown by previous workers to contain the constitutive antifungal phenanthrenes, batatasin I and hircinol (Coxon et al., 1982), and we showed that the inducible compounds in diseased D. rotundata, D. alata ( water yam, isu ewura), D. dumentorum (Esuru), D. bulbifera (Isu awun), and D. mangenotiana (Elephant yam, dagi daji, Ege Esusu)) are dihydrostilbenes (Table 3) with dihydropinosylvin being the most common and abundant in some species and absent in others (Table 3) (Fagboun et al, 1987;Adesanya et al, 1989;Cline et al, 1989;Kaganda and Adesanya, 1990) (Table 3). Other compounds isolated are batatasin III, batasin IV, demethylbatatasin IV, dihydroresveratrol, 3, 5 dimethoxydihyrostilbene with three of them being reported in literature for the first time. ...
... Batatatin IV and batatasin III also inhibited lettuce and Sorghum bicolor seed germination, hypocotyls elongation, and wheat coleoptile development (Hasimoto and Tajima, 1978). The major phytoalexin dihydropinosylvin was not as active (Cline et al., 1989). The result suggested that dihydropinosylvin and demethylbatatasin IV do not possess dormancy-inducing characteristics already established for batatasin IV and other batatasins. ...
... The result suggested that dihydropinosylvin and demethylbatatasin IV do not possess dormancy-inducing characteristics already established for batatasin IV and other batatasins. The role of batatasin IV in disease resistance is not clear, since it accumulates to a low level in Dioscorea species, including earlier investigated D. batatas (Takasugi et al, 1987;Cline et al, 1989), (Figure 1) and has also been reported to occur naturally in D. batatas by some other workers (Hashimoto et al, 1972). ...
... 17) :¾¾(Musa paradisiaca)ö Fusarium oxysporum 6"> Wj <º musanolones C-F zb ÷'Bº ê ®. 18) Â(Orchids) mycorrhyzal G 6">îj r orchinol, hircinol, loroglossol ÷'>, 19) batatasin" piceatannolf '' ²(yam) Botryodiplodia theobromae, Ò û>>& Colletotrchum falcatum 6">îj r W>Ú G Wj º zb. 20,21) 3 ¶# b~ ãÖ 6"B ÷ö~ «~ö ç&ì W>º phytoalexinf &B "(family) >&öB ßWj . ¯ Leguminosae"º flavonoidsê, Cruciferae"º indole FêÚ, Solanaceae"º sesquiterpenoidsê, Umbelliferae"º coumarinê " W B. ...
... 22,23) Kievitone" phaseollinef cowpea (Striga gesnerioides), bean(Phaseolus vulgaris)öB W>º phytoalexinbB Colletotrichum destructivum, C. lindemuthianum f Helminthosporium carbonum ÷öö &~ &Wj . [21][22][23][24]27,31) Casbenef bî ¶(Ricinus communis)öB W>º "º phytoalexinbB Rhizopus stolonifer, Aspergillus niger, Fusarium moniliformeö &~ &Wj <º. 36) Desoxyhemigossypol, hemigossypol f z(Gossypium barbadense)& Xanthomonas campestris, Verticillium dahliae b ÷öb 6">îj r Fê>Ú &Wj ¦. 37,38) Indole-sulfur z>. ...
Pathogens, insects and weeds have significantly reduced agricultural productivity. Thus, to increase the pro-ductivity, synthetic agricultural chemicals have been overused. However, these synthetic compounds that are different from natural products cannot be broken down easily in natural systems, causing the destruction of soil quality and agricultural environments and the gradually difficulty in continuous agriculture. Now agricul-ture is faced with the various problems of minimizing the damage in agricultural environments, securing the safety of human health, while simultaneously increasing agricultural productivity. Meanwhile, plants produce secondary metabolites to protect themselves from external invaders and to secure their region for survival. Plants infected with pathogens produce antibiotics phytoalexin; monocotyledonous plants produce flavonoids and diterpenoids phytoalexins, and dicotylodoneous plant, despite of infected pathogens, produce family-spe-cific phytoalexin such as flavonoids in Leguminosae, indole derivatives in Cruciferae, sesquitepenoids in Solan-aceae, coumarins in Umbelliferae, making the plant resistant to specific pathogen. Growth inhibitor or antifeedant substances to insects are terpenoids pyrethrin, azadirachtin, limonin, cedrelanoid, toosendanin and fraxinellone/dictamnine, and terpenoid-alkaloid mixed compounds sesquiterpene pyridine and norditerpenoids, and azepine-, amide-, loline-, stemofoline-, pyrrolizidine-alkaloids and so on. Also plants produces the sub-stances to inhibit other plant growths to secure the regions for plant itself, which is including terpenoids essen-tial oil and sesquiterpene lactone, and additionally, benzoxazinoids, glucosinolate, quassinoid, cyanogenic glycoside, saponin, sorgolennone, juglone and lots of other different of secondary metabolites. Hence, phytoal-exin, an antibiotic compound produced by plants infected with pathogens, can be employed for pathogen con-trol. Terpenoids and alkaloids inhibiting insect growth can be utilized for insect control. Allelochemicals, a compound released from a certain plant to hinder the growth of other plants for their survival, can be also used directly as a herbicides for weed control as well. Therefore, the use of the natural secondary metabolites for pest control might be one of the alternatives for environmentally friendly agriculture. However, the natural substances are destroyed easily causing low the pest-control efficacy, and also there is the limitation to pro-ducing the substances using plant cell. In the future, effects should be made to try to find the secondary metabolites with good pest-control effect and no harmful to human health. Also the biosynthetic pathways of secondary metabolites have to be elucidated continuously, and the metabolic engineering should be applied to improve transgenics having the resistance to specific pest.
... La producción de estos compuestos se ve favorecida por la irradiación con luz U.V. (Creasy, 1988) (Jeandet, 1991) y por heridas en los cotiledones en el caso de cacahuete (Arora, 1991 ). También se producen fitoalexinas con estructura de dihidroxiestilbeno en Dioscorea bulbifera y D. dumentorum cuando se infectan con el inductor Botryodiplodia theobromae (), y en la batata de agua (Dioscorea alata), con el mismo inductor (Cline, 1989). El primer caso de fitoalexina de tipo estilbeno encontrado en una planta de la familia de las Poáceas, la caña de azúcar, es piceatannol, que se produce cuando se infecta con Colletotrichum falcatum (Brinker, 1991). ...
This article covers the studies on phytoalexins activity of phenolic compounds (cinnamic acids, flavonoids, isoflavonoids, deoxianthocyanins, stilbenes, coumarins, chromones) against fungi and bacteria. The relationship between hydrophilic-lipophilic balance activity is reported.
Finally some reports on the preparation of synthetic phytoalexins sharing structural similarities with the natural ones (stilbenes, epi-catechin derivatives), of commercial interest as pesticides, insecticides and fungicides, are revised.
... La producción de estos compuestos se ve favorecida por la irradiación con luz U.V. (Creasy, 1988) (Jeandet, 1991) y por heridas en los cotiledones en el caso de cacahuete (Arora, 1991 ). También se producen fitoalexinas con estructura de dihidroxiestilbeno en Dioscorea bulbifera y D. dumentorum cuando se infectan con el inductor Botryodiplodia theobromae (), y en la batata de agua (Dioscorea alata), con el mismo inductor (Cline, 1989). El primer caso de fitoalexina de tipo estilbeno encontrado en una planta de la familia de las Poáceas, la caña de azúcar, es piceatannol, que se produce cuando se infecta con Colletotrichum falcatum (Brinker, 1991). ...
... It is believed that fungal infections of yam tuber tissue lead to the activation of certain enzymes in the tissue resulting in the production of a compound with antifungal activity. Ebukanson (1989) associates Dioscorea dumetorum's resistance to infection to the rise in the rate of phenolic acid, while Cline et al. (1989) observed the emission of phytoalexins in Dioscorea alata that had been inoculated with B. theobromae. ...
Severity of storage rots in different sections of white yam tubers (Dioscorea rotundata Poir.) was investigated. Yam samples with rots were collected from a yam barn and from selected markets in Accra, Ghana, to identify the most predominant pathogens associated with the rots. Nine fungal spoilage microorganisms, including Aspergillus flavus, Aspergillus niger, Botryodiplodia theobromae, Fusarium culmorum, Fusarium oxysporium, Fusarium sp., Penicillium brevi-compactum, Penicillium sp. and Rhizopus stolonifer and a bacterium species Erwinia carotovora were identified. The mean incidence of occurrence of the organisms on rotten tissues ranged from 1.2% to 28.5%. Of the 10 microorganisms isolated, B. theobromae, F. oxysporium and R. stolonifer were the most frequently encountered spoilage microorganisms in the markets. E. carotovora, Fusarium solani and Penicillium sp. were relatively sparse (incidence not exceeding 3%) compared to the other yam spoilage microorganisms. The surface area and weight of necrotic tissue induced by the spoilage fungi in the various zones of the tubers over a 28-day storage period were assessed. All the spoilage microorganisms produced rots in the yams, although to different degrees. The severity of the rots increased in weight and area over the period when the tubers were in store but were normally not significantly different in the zones of tubers. There was, however, a linear progression of rots in the various zones of the yam tubers. Although there was generally no significant (P ≥ 0.05) difference in the severity of rots induced by the different microorganisms in the tubers, R. stolonifer commonly induced more rot in the zones of the tubers compared to B. theobromae and F. oxysporium.
Natural products of microbial and plant origin which exhibit plant growth regulating activities are reviewed. Phytohormones such as auxins, cytokinins, gibberellins, abscisic acid and ethylene are not included. The review only surveys low molecular weight compounds that have been chemically characterized and have been reported to induce regulatory responses in plants. The chemical structures, the occurrence and physiological activities of these endogenous plant growth regulators are represented.
Applying voltammetric, spectroscopic, and molecular docking technology, the binding properties of batatasin derivatives with HSA were systematically estimated. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) results showed that the common irreversible oxidation peaks of these compounds at 0.50–0.60 V were an adsorption process with equal numbers of electrons and protons. These compounds could interact with HSA and form non-electroactive complexes, at a binding ratio of 1:1. Comparing their association constants with HSA, 2-hydroxy-3,5-dimethoxy-bibenzyl was the strongest, following by demethyl batatasin IV, 2,3-dihydroxy-bibenzyl and 2-(1-phenethyl)phenol which were basically comparable. The equal fluorescent emission point proved further that these compounds interacted with HSA indeed and new complexes generated. The compounds caused a large reduction of α-helix structure in HSA and extension of its peptide chain which were proved by UV-Vis and CD spectrometric results. Molecular docking results directly demonstrated that the compounds bound near Trp-214 in subdomain IIA mainly through hydrogen bonds.
The pepper (Capsicum annuum L.) fruits, which are ripering (green streaked with red), have been inoculated with several biotic elidtors (Phytophthora capsici L., Monilinia fructigena (Aderh ex. Ruhl) Honey. Alternaria alternata (Fr.) Keissler, Bacillus thuringiensis var. israelensis. Bacillus sphaericus. Pseudomonas syringae pv. tomato). Then, the changing of capsidiol amounts in fruit tissues and diffusates within 1-5 days have been investigated by using GLC method. After wards, the results obtained were compared. The highest accumulation of capsidiol was found in both fruit tissue and collected diffusate for A. alternats elicitor. The effects of the non pathogenic three bacteria were different, and a lesser amount of capsidiol was found when compared to fungi For the Pseudomonas s. pv. tomato elicitor, the highest amount of capsidiol was found in both fruit tissue and collected diffusates.
Plants of genus Dioscorea have long been served as important carbohydrate-stuffed foods in the tropical and subtropical regions, and utilized as traditional herb medicines to enhance digestive function, improve anorexia, and treat diarrhea in oriental countries. It is known that around 600 species of Dioscorea are distributed in the world including 107 species in Asia, but actually utilized Dioscorea species are restricted to small numbers. Phytochemical investigations for Dioscorea species have revealed a number of chemical components such as sapogenins, saponins, phenanthrenes, stilbenes, diterpenes and purine derivatives. According to recent pharmacological studies, Dioscorea species possess significant antioxidant, antibacterial and anti-inflammatory activities as well as anticancer, antidiabetic, cholesterol-lowering and hypolipidemic effects. Here, sev en Dioscorea species (D. batatas, D. japonica, D. bulbifera, D. opposita, D. tokoro, D. nipponica and D. alata), mainly distributed and used in Korea, China, and Japan, are reviewed to provide their botanical, phytochemical and pharmacological properties were described.
Dioscorea mangenstiana tuber infected with Botryodiplodia theobromae gave β-sitosterol, dihydropinosylvin, and a 4,2′-dihydroxy-3,5-dimethoxydihydrostilbene as its major inducible constituents in the ethylacetate extract.
We established Dioscorea bulbifera (aerial yam) cell suspension cultures to study the expression of defense-related genes upon elicitation with the yam pathogenic
ascomycete Colletotrichum gloeosporioides. The induction of phenylalanine-ammonia lyase (PAL) mRNA, coding for a key enzyme involved in phytoalexin biosynthesis, was
observed upon elicitation. Using RT-PCR, we isolated an elicited cDNA clone with an open reading frame of 453 nucleotides
which showed high homology to cDNA sequences of pathogenesis-related proteins belonging to the PRP-4 group. Yam PRP-4 expression is increased in elicited cell cultures as well as in elicited leaves, and is encoded by a small multigene family.
This is the first example for the cloning of a cDNA that might be involved in defense reactions of yam plants.
Effects on growth, mostly of an inhibitory nature, have been attributed to phenolic compounds in vivo and in vitro. This
suggests that l-α-aminooxy-β-phenylpropionic acid (l-AOPP), a competitive inhibitor of phenylalanine ammonia-lyase (PAL), the enzyme controlling the first step in phenylpropanoid
synthesis, might stimulate growth in soybean suspension cultures (Glycine max, cv. Acme). The promotive effect of l-AOPP, measured as an increase in cell number, was more clearly detected in the growth-limiting condition of cytokinin starvation.
At least one more cell division cycle was completed in the presence of l-AOPP before growth by division ceased and growth continued by expansion only. Phenolic acids are known to conjugate with
polyamines, modulating the free levels of these plant growth substances. Thus, the effect of l-AOPP on the titers of free and conjugated polyamines (putrescine, spermidine, and spermine) was investigated by high performance
liquid chromatography in the course of cytokinin starvation. An increased level of free putrescine was detected in the presence
of l-AOPP relative to controls, especially in the initial period before growth became restricted to cell expansion. The decrease
in free putrescine associated with the cessation of cell division was temporarily delayed, suggesting that an interaction
between phenolic acids and polyamines is involved in the mechanism of growth promotion by l-AOPP.
Bioassay-guided fractionation led to the isolation of eight compounds from Stemona sessilifolia. Of the eight isolates, three new bibenzyls, stilbostemins M-O (1-3), and a new tocopherol, 6-methoxy-3,4-dehydro-delta-tocopherol (4) were revealed together with four known compounds 3,5-dihydroxy-2'-methoxy bibenzyl (5), 3,5-dihydroxy bibenzyl (6), beta-tocopherol (7), and gamma-tocopherol (8). Compounds 5, 6, and 8 exhibited strong antibacterial activities against Staphylococcus aureus and S. epidermidis.
Three growth inhibitors, for which the names batatasins I, II and III are proposed, occur in dormant yam bulbils. Application of these inhibitors suppresses the sprouting of bulbils, and the inhibition is reversible by low-temperature stratification. Batatasins I and III were isolated as crystals and partially characterized as phenotic compounds not identical with known inhibions.
The tubers and/or aerial bulbils of 13 species of Dioscorea, mostly of tropical origin, and one species each of Rajania and Tamus, were examined for the presence of batatasins. These phenolics have previously been reported in the temperate species D. opposite. One or more batatasins were found in either tubers or bulbils of most species examined, including taxa from both Old and New Worlds, and with annual or perennial tubers. Batatasin I was the most widespread in occurrence, followed by B-II, while B-III, B-IV and B-V were comparatively rare. Only the buibils of D. opposite contained all five batatasins.
Two new compounds, batatasins IV and V were isolated from dormant bulbils of Chinese yam (Dioscorea batatas) and shown to be 2′,3-dihydroxy-5-methoxybibenzyl and 2′-hydroxy-3,4,5-trimethoxybibenzyl, respectively. An analogue, 3,4′-dihydroxy-5-methoxybibenzyl was synthesized. Inhibitory activities of these three compounds as well as batatasin I (6-hydroxy-2,4,7-trimethoxyphenanthrene) and batatasin III (3,3′-dihydroxy-5-methoxy-bibenzyl) in lettuce seed germination, lettuce hypocotyl elongation and wheat coleoptile section elongation tests are described.
Batatasin, which occurs in dormant bulbils of yams (Dioscorea batatas Decne.) and induces dormancy in this organ has been shown by spectrometric analysis and synthesis to be 3,3′-dihydroxy-5-methoxy-bibenzyl.
Phaseollin and pisatin accumulated in bean and pea cotyledons respectively, after incubation at 25 °C following treatment with mercuric chloride. Both the duration of treatment and concentration of mercuric chloride determined maximal phytoalexin concentrations. Highest levels of both phytoalexins occurred when cell damage caused by mercuric chloride was microscopically visible. With increasing amounts of dead cells the concentrations of phytoalexins decreased, and in some treatments no phytoalexins were formed even when some tissue was still alive. The accumulation of phaseollin appeared to be more closely associated with cell death than the accumulation of pisatin.
2′,3-Dihydroxy-5-methoxybibenzyl (Batatasin IV), its demethyl derivative and 3,5-dihydroxybibenzyl (dihydropinosylvin) were isolated only from flesh of Dioscorea rotundata infected with Botryodiplodia theobromae and may therefore be considered phytoalexins. These compounds were found to be antifungal using bioassays with Cladosporium cladosporioides, Botryodiplodia theobromae, Aspergillus niger and Penicillium schlerotgenum. Dihydro-pinosylvinin also exhibited strong antibacterial activity against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli.
Chromatographic investigation of a methanolic extract of white lupin roots has revealed the presence of six new dihydrofuranoisoflavones (lupinisoflavones A-F). Three monoprenylated (3,3-dimethylallyl-substituted) isoflavones (wighteone, luteone and licoisoflavone A), two diprenylated isoflavones [6,3′-di(3,3-dimethylallyl)genistein (lupalbigenin) and 6,3′-di(3,3-dimethylallyl)-2′-hydroxygenistein (2′-hydroxylupalbigenin)] and two pyranoisoflavones (parvisoflavone B and licoisoflavone B) have also been isolated from the same source. In addition to genistein, leaf extracts of L. italbus contain 3′-O-methylorobol which is presumed to be the precursor of lupisoflavone [5,7,4′-trihydroxy-3′-methoxy-6-(3,3-dimethylallyl)isoflavone]. Probable biogenetic relationships between the prenylated, and dihydrofurano-and pyrano-substituted isoflavones in roots and leaves of L. albus are briefly discussed.
Recent progress in the study of plant polyphenol oxidases is critically reviewed. Two main groups are recognized: the catecholoxidases and the laccases. Their purification, subcellular location and protein properties are described. Attention is also given to their activation and induction, their function and evolution.
Batatasin I was isolated from non–dormant bulbils of Dioscorea opposita Thunb. (= D. batatas Decne.). Such non–dormant bulbils were devoid of the bibenzyl derivatives batatasins III, IV and V. It is therefore suggested that the dormancy of the yam bulbils is determined primarily by the bibenzyl batatasins.
PHYTOALEXINS are inducibly formed higher plant metabolites that are antibiotic to certain potential plant pathogens1. At least 75 plant species representing 20 families have been shown to accumulate phytoalexins in response to infection1–3. Phytoalexins also accumulate in plants in response to various agents termed elicitors1, including substances of pathogen origin (biotic elicitors) and abiotic elicitors such as heavy metal salts and detergents1–3. Elicitors may be useful for investigation of the molecular basis of phytoalexin production or disease resistance expression1. However, the mechanisms by which such diverse elicitor molecules induce phytoalexin accumulation in plants are unknown. I have found4 that levels of glyceollin, a phytoalexin produced by soybean [Glycine max (L.) Merr.] hypocotyls in response to infection with the fungal pathogen Phytophthora megasperma var. sojae A. A. Hildb., are regulated by relative rates of induced biosynthesis and constitutive degrading activity. I report here the effects of various biotic and abiotic elicitors on biosynthesis and degradation of glyceollin in soybean tissues.
Peak production of phenylalanine and tyrosine ammonia lyase activity occurs during late logarithmic phase in the growth of batch cultures of the yeast, Sporobolomyces roseus. There is some evidence that two enzymes are involved although the production and activity of each enzyme appears to be under common control. Replacement media containing either phenylalanine or tyrosine stimulate production of both enzymes whereas cinnamic acid represses their formation. The activities of both enzymes are also inhibited by cinnamic or p-coumaric acids.
An extract from the peel of yams (Dioscorea rotundata) showed anti-fungal activity towards both Cladosporium cladoporioides and a variety of ya
An induced and six preformed antifungal compounds were isolated from Chinese yam (Dioscorea batatas) inoculated with the bacterium Pseudomonas cichorii. The induced compound, a phytoalexin, was identified as dihydropinosylvin. The preformed compounds were characterized as oxygenated bibenzyls and phenanthrenes.
An enzyme was found which catalyzes the deamination of l-tyrosine, giving equimolar amounts of trans-p-coumaric acid and ammonia as the products. This enzyme (tyrase) was readily detected in sorghum, barley, rice, wheat, oat, corn and sugar cane plants; but not in pea, lupine, alfalfa or white sweet clover plants, or in yeast. Tyrase was concentrated in the stems of barley rather than the leaves, and reached its maximum concentration at about the time the heads were emerging. The crude, soluble protein extracted from an acetone powder of barley stems was purified about forty-fold with respect to tyrase. Tyrase preparations from this source were also found to convert dl-m-tyrosine to m-coumaric acid and ammonia, and have been shown by Koukol and Conn to contain an enzyme (phenylalanase) which can catalyze the conversion of l-phenylalanine to cinnamic acid and ammonia. The data suggest that tyrase is distinct from the enzymes (or enzyme) catalyzing the deaminations of phenylalanine and m-tyrosine.
The properties of phenylalanine ammonia-lyase from higher plants and its position in phenylpropanoid metabolism are briefly reviewed. Emphasis is then
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