scispace - formally typeset
Search or ask a question
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.


Papers
More filters
Journal ArticleDOI
TL;DR: Lignification appeared to be induced almost exclusively by fungi, unlike phytoalexin production which can also be elicited by a wide range of abiotic treatments.
Abstract: A range of abiotic treatments reported to induce phytoalexin accumulation in various plants failed to induce lignification in a wounded primary wheat leaf system The inducers included antimetabolites, metabolic inhibitors, DNA-intercalating compounds, basic polypeptides, oxidising and reducing agents, halogen anions, heavy metal ions and uv irradiation Only mercuric ions elicited a response A range of fungi, including species normally of saprophytic habit, species pathogenic on plants other than wheat, and wheat pathogens all elicited lignification Yeasts and bacteria, unlike the mycelial fungi, were poor elicitors of the response Thus lignification appeared to be induced almost exclusively by fungi, unlike phytoalexin production which can also be elicited by a wide range of abiotic treatments

39 citations

Journal ArticleDOI
TL;DR: A number of biphenyls and dibenzofurans were tested for their in vitro antibacterial activity against some Erwinia amylovora strains and the most efficient compound was 3,5-dihydroxybiphenyl (MIC=115 μg/ml), the immediate product of bipenyl synthase which initiates phytoalexin biosynthesis.

39 citations

Journal ArticleDOI
TL;DR: The autofluorescent material also accumulated in hypersensitive necrotic cells of visibly symptomless soybean leaves inoculated with low concentrations of incompatible bacteria, thus suggesting that phytoalexin accumulation and hypersensitive cell death are normal components of resistance.
Abstract: Small groups of 1 to 5 necrotic plant cells were observed in resistant soybean leaves 9 h after inoculation with high concentrations of Pseudomonas syringae pv. glycinea cells that eventually caused confluent hypersensitive necrosis. Similar cell death patterns were observed 24 h after inoculation with low bacterial concentrations which elicited no visible hypersensitive response. Dead cells were efficiently detected in fresh tissue by their inability to concentrate sodium fluorescein, a fluorescent vital stain. In compatible tissue, microscopic cell death was not observed until 24 to 36 h after inoculation with high concentrations of bacteria and appeared as large zones of necrosis comprising more than 100 cells. Microscopic cell death in the incompatible response was inhibited by blasticidin S, a protein synthesis inhibitor in soybean, therefore suggesting that the processes leading to host cell death are dependent on translational events. Autofluorescent material accumulated only in hypersensitive collapsed mesophyll cells of leaves inoculated with incompatible bacterial races. Preliminary evidence suggests that the autofluorescence may be due to accumulation of the phytoalexin, glyceollin. The autofluorescent material also accumulated in hypersensitive necrotic cells of visibly symptomless soybean leaves inoculated with low concentrations of incompatible bacteria, thus suggesting that phytoalexin accumulation and hypersensitive cell death are normal components of resistance.

39 citations

Journal ArticleDOI
TL;DR: The remarkable metabolism of the cruciferous phytoalexin cyclobrassinin by the phytopathogenic root rot and blackleg fungi and the chemistry involved in the structure determination of the intermediates of these three apparently different pathways and their antifungal activities are described.
Abstract: The remarkable metabolism of the cruciferous phytoalexin cyclobrassinin by the phytopathogenic root rot (Rhizoctonia solani Kuhn) and blackleg [Phoma lingam (Tode ex Fr.) Desm., asexual stage of Leptosphaeria maculans (Desm.) Ces. et de Not.] fungi is reported. It was established that R. solani metabolized and detoxified cyclobrassinin via the phytoalexin brassicanal A, which was further transformed into nontoxic products. Detoxification of cyclobrassinin in P. lingam avirulent isolate Unity occurred via the phytoalexin brassilexin, whereas the detoxification in P. lingam virulent isolate BJ 125 occurred via the phytoalexin dioxibrassinin. The chemistry involved in the structure determination of the intermediates of these three apparently different pathways and their antifungal activities are described. In addition, efficient syntheses of both phytoalexins brassicanal A and brassilexin by mimicry of the fungal biotransformation route are reported. Implications of these unprecedented transformations are discussed.

39 citations

Journal ArticleDOI
TL;DR: It is indicated that ABA is not required per se for the induction of capsidiol synthesis but is essentially implicated in a stress-response checkpoint to fine-tune the amplification of capsIDiol synthesis in challenged plants.
Abstract: In the Solanaceae, biotic and abiotic elicitors induce de novo synthesis of sesquiterpenoid stress metabolites known as phytoalexins. Because plant hormones play critical roles in the induction of defense-responsive genes, we have explored the effect of abscisic acid (ABA) on the synthesis of capsidiol, the major wild tobacco (Nicotiana plumbaginifolia) sesquiterpenoid phytoalexin, using wild-type plants versus nonallelic mutants Npaba2 and Npaba1 that are deficient in ABA synthesis. Npaba2 and Npaba1 mutants exhibited a 2-fold higher synthesis of capsidiol than wild-type plants when elicited with either cellulase or arachidonic acid or when infected by Botrytis cinerea. The same trend was observed for the expression of the capsidiol biosynthetic genes 5-epi-aristolochene synthase and 5-epi-aristolochene hydroxylase. Treatment of wild-type plants with fluridone, an inhibitor of the upstream ABA pathway, recapitulated the behavior of Npaba2 and Npaba1 mutants, while the application of exogenous ABA reversed the enhanced synthesis of capsidiol in Npaba2 and Npaba1 mutants. Concomitant with the production of capsidiol, we observed the induction of ABA 8′-hydroxylase in elicited plants. In wild-type plants, the induction of ABA 8′-hydroxylase coincided with a decrease in ABA content and with the accumulation of ABA catabolic products such as phaseic acid and dihydrophaseic acid, suggesting a negative regulation exerted by ABA on capsidiol synthesis. Collectively, our data indicate that ABA is not required per se for the induction of capsidiol synthesis but is essentially implicated in a stress-response checkpoint to fine-tune the amplification of capsidiol synthesis in challenged plants.

39 citations


Network Information
Related Topics (5)
Abscisic acid
12.8K papers, 587K citations
81% related
Cell wall
6.3K papers, 336.9K citations
81% related
Agrobacterium
8.8K papers, 328.1K citations
80% related
Arabidopsis thaliana
19.1K papers, 1M citations
80% related
Hordeum vulgare
20.3K papers, 717.5K citations
79% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202321
202256
202119
202013
201922
201815