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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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Journal ArticleDOI
TL;DR: Treatment of potato tuber tissues with l-hydroxy-2-oxo-3,3-bis(2-aminoethyl)1-triazene (NOC-18), an NO-releasing compound, induced the accumulation of the potato phytoalexin rishitin, suggesting a phytochemical inducing activity for NO.
Abstract: We investigated whether nitric oxide (NO) radical could induce phytoalexin production. Treatment of potato tuber tissues with 1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)1-triazene (NOC-18), an NO-releasing compound, induced the accumulation of the potato phytoalexin rishitin. This induction was inhibited by carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline 1-oxyl-3-oxide (carboxy-PTI0), an NO-specific scavenger, or by Tiron, a radical scavenger, suggesting a phytoalexin inducing activity for NO.

210 citations

Journal ArticleDOI
TL;DR: Recent advances in the discovery, biosynthesis, elicitation and functional characterization of monocot terpenoid phytoalexins are discussed, including conclusive evidence now exists for multiple plant receptors of fungal-derived chitin elicitors, phosphorylation of membrane-associated signaling complexes, activation of mitogen-activated protein kinase, involvement of phytohormone signals, and the existence of transcription factors.
Abstract: Summary A long-standing goal in plant research is to optimize the protective function of biochemical agents that impede pest and pathogen attack. Nearly 40 years ago, pathogen-inducible diterpenoid production was described in rice, and these compounds were shown to function as antimicrobial phytoalexins. Using rice and maize as examples, we discuss recent advances in the discovery, biosynthesis, elicitation and functional characterization of monocot terpenoid phytoalexins. The recent expansion of known terpenoid phytoalexins now includes not only the labdane-related diterpenoid superfamily but also casbane-type diterpenoids and β-macrocarpene-derived sequiterpenoids. Biochemical approaches have been used to pair pathway precursors and end products with cognate biosynthetic genes. The number of predicted terpenoid phytoalexins is expanding through advances in cereal genome annotation and terpene synthase characterization that likewise enable discoveries outside the Poaceae. At the cellular level, conclusive evidence now exists for multiple plant receptors of fungal-derived chitin elicitors, phosphorylation of membrane-associated signaling complexes, activation of mitogen-activated protein kinase, involvement of phytohormone signals, and the existence of transcription factors that mediate the expression of phytoalexin biosynthetic genes and subsequent accumulation of pathway end products. Elicited production of terpenoid phytoalexins exhibit additional biological functions, including root exudate-mediated allelopathy and insect antifeedant activity. Such findings have encouraged consideration of additional interactions that blur traditionally discrete phytoalexin classifications. The establishment of mutant collections and increasing ease of genetic transformation assists critical examination of further biological roles. Future research directions include examination of terpenoid phytoalexin precursors and end products as potential signals mediating plant physiological processes.

210 citations

Journal ArticleDOI
TL;DR: In this paper, the antidiabetic properties of resveratrol in streptozotocin-nicotinamide induced experimental diabetes in rats were evaluated and the results showed that 5mg/kg−1/b for 30 days resulted in significant (p

209 citations

Journal ArticleDOI
TL;DR: Results indicate that BcatrB is a determinant in sensitivity of B. cinerea to plant defense compounds and fungicides.
Abstract: During pathogenesis, fungal pathogens are exposed to a variety of fungitoxic compounds. This may be particularly relevant to Botrytis cinerea, a plant pathogen that has a broad host range and, consequently, is subjected to exposure to many plant defense compounds. In practice, the pathogen is controlled with fungicides belonging to different chemical groups. ATP-binding cassette (ABC) transporters might provide protection against plant defense compounds and fungicides by ATP-driven efflux mechanisms. To test this hypothesis, we cloned BcatrB, an ABC transporter-encoding gene from B. cinerea. This gene encodes a 1,439 amino acid protein with nucleotide binding fold (NBF) and transmembrane (TM) domains in a [NBF-TM6]2 topology. The amino acid sequence has 31 to 67% identity with ABC transporters from various fungi. The expression of BcatrB is up regulated by treatment of B. cinerea germlings with the grapevine phytoalexin resveratrol and the fungicide fenpiclonil. BcatrB replacement mutants are not affected in saprophytic growth on different media but are more sensitive to resveratrol and fenpiclonil than the parental isolate. Furthermore, virulence of deltaBcatrB mutants on grapevine leaves was slightly reduced. These results indicate that BcatrB is a determinant in sensitivity of B. cinerea to plant defense compounds and fungicides.

209 citations

Journal ArticleDOI
TL;DR: It is demonstrated that endopolygalacturonic acid lyase elicits phytoalexin accumulation by releasing fragments from pectic polysaccharides in plant cell walls through heat-stable elicitor-active material solubilized from soybean cell walls.
Abstract: Heat-labile elicitors of phytoalexin accumulation in soybeans (Glycine max L. Merr. cv Wayne) were detected in culture filtrates of Erwinia carotovora grown on a defined medium containing citrus pectin as the sole carbon source. The heat-labile elicitors were highly purified by cation-exchange chromatography on a CM-Sephadex (C-50) column, followed by agarose-affinity chromatography on a Bio-Gel A-0.5m gel filtration column. The heat-labile elicitor activity co-purified with two α-1,4-endopolygalacturonic acid lyases (EC 4·2·2·2). Endopolygalacturonic acid lyase activity appeared to be necessary for elicitor activity because heat-inactivated enzyme preparations did not elicit phytoalexins. The purified endopolygalacturonic acid lyases elicited pterocarpan phytoalexins at microbial-inhibitory concentrations in the soybean-cotyledon bioassay when applied at a concentration of 55 nanograms per milliliter (1 × 10−9 molar). One of these lyases released heat-stable elicitors from soybean cell walls, citrus pectin, and sodium polypectate. The heat-stable elicitor-active material solubilized from soybean cell walls by the lyase was composed of at least 90% (w/v) uronosyl residues. These results demonstrate that endopolygalacturonic acid lyase elicits phytoalexin accumulation by releasing fragments from pectic polysaccharides in plant cell walls.

206 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202321
202256
202119
202013
201922
201815