Rapid Switching of Plant Gene Expression Induced by Fungal Elicitor

The pattern of messenger RNA synthesis in suspension-cultured bean cells ( Phaseolus vulgaris L.) was analyzed by blot hybridization and in vitro translation of newly synthesized messenger RNA. The RNA was separated from preexisting RNA by organomercurial affinity chromatography after in vivo labeling with 4-thiouridine. The elicitor induced the synthesis of messenger RNA's encoding phenylalanine ammonia-lyase, chalcone synthase, and chalcone isomerase, three enzymes of phenylpropanoid metabolism involved in the synthesis of isoflavonoidderived phytoalexins. This is part of a rapid and extensive change in the pattern of messenger RNA synthesis directing production of a set of proteins associated with expression of disease resistance.