De Novo Messenger RNA and Protein Synthesis Are Required for Phytoalexin-mediated Disease Resistance in Soybean Hypocotyls

Abstract

Hadwiger and co-workers (5,7,14) found that pisatin, a phytoalexin produced in pea plants, could be induced by various chemicals which were presumed to affect the conformation of DNA; based on this and inhibitor experiments they (7, 14) suggested that pisatin production depended upon both de novo RNA and protein synthesis. To date, however, no systematic study that would link de novo RNA and protein synthesis, phytoalexin production, and disease resistance has been conducted. Plant and Fungus. The soybean cultivar Harosoy 63 (resistant to race 1 of P. megasperma var. sojae) was grown as described previously (22) and used throughout the experiments unless otherwise specified. Race 1 of P. megasperma var. sojae was maintained on V-8 juice agar. For inoculum production, the fungus was grown for 3 to 5 days in a pea broth medium (10) and rinsed with deionized H20 prio. to inoculation.Seven-to 8-day-old plants were cut at the base of the hypocotyls and the cut ends placed in deionized H20 or aqueous solutions of either blasticidin S, a protein synthesis inhibitor (4)

Molecular Cloning and Ethylene Induction of mRNA Encoding a Phytoalexin Elicitor-Releasing Factor, β-1,3-Endoglucanase, in Soybean

“…glycinea, interaction is one of the best understood gene-for-gene plant-pathogen systems in which the processes leading to accumulation of the phytoalexin glyceollin have been analyzed (25,29). Mycelial walls of the fungus have been shown to be potent elicitors of glyceollin accumulation and their possible role in the induction of phytoalexin accumulation in infected plants has been suggested (25).…”

Immunological evidence that .BETA.-1,3-endoglucanase is the major elicitor-releasing factor in soybean.

“…(Received February 16,1990) INTRODUCTION Inducible production of low molecular weight antibiotic compounds, phytoalexins, appears to confer disease resistance in many plant-fungal interactions3). The induction of phytoalexins in infected plant is presumed to be mediated by an initial recognition process between plant and pathogens which involves recognition of certain unique molecules of pathogen origin, termed elicitors, by receptor-like molecules13) in plants, thereby setting off a cascade of biochemical events leading ultimately to phytoalexin accumulation11, 12,14,16).…”

Les phytoalexines et leur intervention dans la résistance hypersensible aux champignons phytopathogènes

“…Il existe toutefois des exemples où une action sur la respiration cellulaire est signalée (Yoshikawa et al, 1987). Enfin (Yoshikawa et al, 1978b;Yoshikawa, 1983;Chappell et Hahlbrock, 1984;Ryder et al, 1984;Schmelzer et al, 1984;Cramer et al, 1985;Ryder et al, 1986;Hamdan et Dixon, 1987;Kuhn, 1988).…”

“…De même, certains auteurs n'ont pas trouvé de corrélation entre la nécrose et la présence ou l'étendue du développement du parasite (Brown et al, 1966;Ogle et Brown, 1971;Harder et al, 1979aHarder et al, , 1979bRohringer et al, 1979 (Smith, 1982 (Bailey, 1982b (Yoshikawa et al, 1978a(Yoshikawa et al, , 1978bKeen et al, 1981; Long et al, 1985;Rouxel, 1988).…”