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: Oryzalexins A, B and C, isolated from rice leaves infected with P. oryzae as a group of novel phyto-alxins, were confirmed to be (+)-sandaracopimaradiene derivatives by chemical and spectroscopic studies.
Abstract: Oryzalexins A, B and C, isolated from rice leaves infected with P. oryzae as a group of novel phytoalexins, were confirmed to be (+)-sandaracopimaradiene derivatives by chemical and spectroscopic studies, i.e. A: 3-oxy-7-oxo- (I); B: 3-oxo-7-oxy- (II) and C: 3, 7-dioxo-(+)-sandaracopimaradiene (III).
25 citations
TL;DR: It is established that camalexins are slowly biotransformed to the corresponding indole-3-thiocarboxamides, which are further transformed to the indole.3-carboxylic acids, and the potential intermediates that lead to formation of indole -3- Thiazole ring are proposed.
25 citations
TL;DR: Most fungitoxic compounds had not more than one or two polar substituents and methylation of all of these groups removed activity.
Abstract: Three hydroxyflavan phytoalexins and 23 other flavonoid compounds variously substituted in their homocyclic rings were assessed for antifungal activity against Botrytis cinerea and Cladosporium herbarum using sporeling and TLC plate bioassays. The pairs of optical isomers of two of the phytoalexins possessed similar activity. The isoflavan analogue of the phytoalexin 7-hydroxyflavan was active. Most fungitoxic compounds had not more than one or two polar substituents and methylation of all of these groups removed activity. The basis of the antifungal activity of flavonoids is discussed.
25 citations
TL;DR: In this paper, the self defensive substances in rice plant against rice blast disease are described and a convenient synthesis of 16-hydroxy-9Z,12Z,14E-octadecatrienoic acid (1) and 9- hydroxy-1OE, 12Z,15Z-Octadec-catrienic acid is described.
25 citations
TL;DR: The non-host penetration resistance to A. alternata was clearly associated with activation of the jasmonate- and ethylene-signalling pathways and analysis using histochemical staining of GUS activity suggests that defence reactions in non- host penetration resistance are activated locally.
Abstract: SUMMARY When challenged with the necrotrophic fungal pathogen Alternaria alternata Japanese pear pathotype, all tested ecotypes of Arabidopsis plants failed to show hypersensitive cell death, accumulation of detectable levels of reactive oxygen species or accumulation of phytoalexin. We operationally define A. alternata as a non-host pathogen for Arabidopsis plants and show that the protection against A. alternata demonstrated in this study is a non-host penetration resistance. To characterize non-host penetration resistance, we examined the expression patterns of c. 7000 genes by cDNA microarray analysis in Arabidopsis Col-0 plants after inoculation with A. alternata. After inoculation with A. alternata, the transcript levels of 48 genes increased in Col-0 plants. The expression of genes associated with hypersensitive reaction was induced in the non-host penetration resistance to A. alternata, despite the fact that A. alternata had no visible effect on the plants. The non-host penetration resistance to A. alternata was clearly associated with activation of the jasmonate- and ethylene-signalling pathways. In addition, analysis using histochemical staining of GUS activity suggests that defence reactions in non-host penetration resistance are activated locally. The characterization of non-host pathosystem involving Arabidopsis and A. alternata offers an overview of non-host penetration resistance.
25 citations