We are studying the cellular signalling pathway leading to pterocarpan phytoalexin biosynthesis in soybean that is induced by a branched hepta-beta-glucoside originally isolated from the mycelial walls of the phytopathogenic oomycete, Phytophthora megasperma f. sp. glycinea. Our research has focused on the first step in this signal pathway, namely the specific recognition of the hepta-beta-gluc...

Treatment of melon hypocotyls or petioles with an elicitor from Colletotrichum lagenarium, a fungal pathogen of melons, causes an initial transitory inhibition of protein synthesis and, after 18 hours, induces the synthesis of a plant cell wall hydroxyproline-rich glycoprotein (HRGP). Microgram amounts of elicitor are sufficient for maximum elicitation of HRGP when the elicitor is injected into...

An extract of frozen and thawed soybean (Glycine max L. Merr. cv. Wayne) stems is active, in wounded soybean cotyledons, as a heat-labile elicitor of phytoalexins. The elicitor activity of the extract is destroyed by heating to 95 degrees C for 10 minutes. The fraction that contains heat-labile elicitor activity releases heat-stable elicitor-active molecules from purified soybean cell walls. He...

The biosynthesis of a phytoalexin, beta-thujaplicin, in Cupressus lusitanica cell cultures can be stimulated by a yeast elicitor, H(2)O(2), or methyl jasmonate. Lipoxygenase activity was also stimulated by these treatments, suggesting that the oxidative burst and jasmonate pathway may mediate the elicitor-induced accumulation of beta-thujaplicin. The elicitor signalling pathway involved in beta...

A great deal of an elicitor-active oligosaccharide (1.47 g) was obtained from 40 g of polysaccharide laminaran with the guidance of elicitor activity in the bean cotyledon assay. Physicochemical means suggested that the oligosaccharide was a beta-1,3- and beta-1,6-linked triglucoside. This was a partial structure of LN-3, having elicitor activity to alfalfa and bean. The triglucoside exhibited ...

Chlortetracycline (CTC) is known to fluoresce when interacting with Ca2+ in hydrophobic environments such as membranes. CTC fluorescence in potato tubers was rapidly reduced by hyphal wall component-elicitor (HWC-elicitor) from Phytophthora infestans in a dose-dependent manner, suggesting that Ca2+ in the plasma membrane was released by the elicitor. Pre-treatments of the tuber slices with vera...

Fungal elicitor prepared from the cell walls of Aspergillum niger induces multiple responses of Hypericum perforatum cells, including nitric oxide (NO) generation, jasmonic acid (JA) biosynthesis, and hypericin production. To determine the role of NO and JA in elicitor-induced hypericin production, we study the effects of NO scavenger 2- to 4-carboxyphenyl-4,4, 5,5-tetramethylimidazoline-1-oxyl...

Resistance of soybean (Glycine max L.) seedlings to Phytophthora megasperma var. sojae (Pms) is in part due to the accumulation in infected tissue of a compound which is toxic to Pms. The accumulation of this compound, a phytoalexin called glyceollin, is triggered by infection, but it can also be triggered by molecules, "elicitors," present in cultures of Pms. The ability of the Pms elicitor to...

Cultured parsley (Petroselinum crispum) cells respond to treatment with elicitors derived from different species of the genus Phytophthora with transcript accumulation of defense-associated genes and the production of furanocoumarin phytoalexins. Pep-25, an oligopeptide fragment of a Phytophthora sojae 42-kDa cell wall protein, and a cell wall elicitor preparation derived from Phytophthora para...

Active oxygen species (AOS) are central components of the defence reactions of plants against pathogens. Plant respiratory burst oxidase homologues (RBOH) of gp91(phox), a plasma membrane protein of the neutrophil nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, play a prominent role in AOS production. The role of two RBOH from Nicotiana benthamiana, NbrbohA and NbrbohB that encode ...