Topic
Phytoalexin
About: Phytoalexin is a research topic. Over the lifetime, 1161 publications have been published within this topic receiving 63405 citations. The topic is also known as: phytoalexins.
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TL;DR: A single phytoalexin was isolated and purified from 12- to 14-day-old leaves of Cassia obtusifolia L. inoculated with Alternaria cassiae Jurair & Khan and shown to be derived in part from phenylalanine.
Abstract: A single phytoalexin was isolated and purified from 12- to 14-day-old leaves of Cassia obtusifolia L. inoculated with Alternaria cassiae Jurair & Khan. The structure was elucidated by 1H- and 13C-nuclear magnetic resonance and mass spectrometry as 2-(p-hydroxyphenoxy)-5,7-dihydroxychromone. The compound was shown to be derived in part from phenylalanine. Radial growth of A. cassiae was inhibited 50% by the compound at 0.3 millimolar. This moderate toxicity is compensated for by the relatively high levels (3 millimolar) accumulated. Phenoxychromones have been previously reported only as constitutive secondary metabolites in Artemisia capillaris Thunb., in which their function is unknown.
31 citations
TL;DR: Two saprophytic fungi were tested for their ability to induce phytoalexin production by seeds of frog-eye leaf spot and stem canker-resistant and -susceptible soybean cultivars and genistein was found to be an inducibly formed isoflavonoid instead of a constitutive metabolite in the resistant cultivar.
Abstract: Two saprophytic fungi (Mucor ramosissimus and Rhizopus sp.) were tested for their ability to induce phytoalexin production by seeds of frog-eye leaf spot and stem canker-resistant and -susceptible soybean (Glycine max L.) cultivars. Only M. ramosissimus was shown to elicit a response and qualitative differences in phytoalexin accumulation were found between the susceptible and resistant cultivars. Glyceollins I, II, and III and glycinol were isolated from the susceptible cultivar, whereas Glyceollins I, II, and III, glycinol, glyceocarpin, genistein, isoformononetin, and N-acetyltyramine accumulated in the resistant cultivar in response to the same fungal elicitor. Genistein was found to be an inducibly formed isoflavonoid instead of a constitutive metabolite in the resistant cultivar, whereas N-acetyltyramine is described for the first time as a soybean phytoalexin. All the compounds, except genistein, showed fungitoxic activity against Cladosporium sphaerospermum. Spectral data of the pterocarpan phytoalexins, genistein, and N-acetyltyramine are also given in this work.
31 citations
TL;DR: It is proposed that the hydrocarbon 4- epi -eremophila-9,11-diene is a common intermediate in the biosynthesis of all the named compounds and further that 8-hydroxydebneyol is the direct precursor of the phytoalexin cyclodebneyol.
31 citations
TL;DR: It would appear that the 1-methoxy substituent of the indole moiety is introduced downstream from tryptophan and that the post-aldoximes of the glucosinolate pathway are different from the enzymes of the phytoalexin pathway.
31 citations
TL;DR: It is found that in vitro methylation assays of resveratrol by recombinant SbROMT3syn produced pinostilbene as the major product besides a very small amount of pterostilbenes in E. coli.
31 citations