Comparison of mRNA populations coding for phenylalanine ammonia lyase and other peptides from pea tissue treated with biotic and abiotic phytoalexin inducers

Abstract

Pea endocarps were treated with optimal concentrations of biotic and abiotic compounds which are potent inducers of phytoalexin production and of certain disease resistance responses. Total cell mRNA which accumulated during induction was translated in vitro with a rabbit reticulocyte protein synthesizing system. Both the synthesis of phenylalanine ammonia lyase (PAL) and the two-dimensional separations of total labelled proteins from the various inducer treatments were compared. The increases in the synthesis of the observed specific proteins, induced by the DNA-specific compounds, result from the increased translation activity of mRNAs within the pea tissue. The induction of PAL and other specific proteins by chitosan, a glucosamine polymer in fungal walls, resembled the patterns induced by Fusarium solani f. sp. phaseoli macroconidia. There were only minor differences in protein induction by the F. solani f. sp. phaseoli macroconidia, actinomycin D, 4,5′8-trimethylpsoralen plus 366 nm UV light, and 260 nm UV light. Major shifts in the protein synthesis patterns were found in proteins translated from the RNA from CdCl 2 and quinacrine-treated tissue. Our results suggest that certain abiotic and biotic compounds which induce responses similar to those induced in the authentic “resistance response” may be useful in investigating the mode by which these responses are induced.