DIFFERENTIAL PROTEIN-METABOLISM AND GENE-EXPRESSION IN TOMATO FRUIT DURING WOUNDING STRESS

Changes in protein and RNA levels which occur in tomato (Lycopersicon esculentum cv. Pik-red) fruit tissue upon wounding were analyzed. Antibodies to nine plant proteins were used to identify the related cross-reactive proteins in tomato fruit tissue and quantify their abundance during wounding. Antibodies tested were pathogenesis-related proteins (PR-1a, 1b, 1c; PR-2, N, O; PR-P, Q; basic chitinase), plastid proteins (sorbitol-6-phosphate dehydrogenase; acyl carrier protein; large subunit of Rubisco), cellulase and 33-kD cationic peroxidase. Marked differences in mRNA populations were also detected when the protein translation products following in vitro translation of poly(A)+ RNAs isolated from unwounded and wounded fruit tissue were compared. More direct evidence for the changes in mRNA levels was obtained by using specific cDNA probes, isolated from a cDNA library of wounded tomato pericarp tissue. Two cDNA clones identified RNAs that were induced upon wounding while a third cDNA clone identified a transcript whose abundance decreased.