Plant Cell Physiol. 32(7): 1057-1065 (1991) JSPP © 1991 Differential Protein Metabolism and Gene Expression in Tomato Fruit during Wounding Stress' Roshni A. Mehta 2 ' 3 , Barbara L. Parsons 2 , Arkesh M. Mehta 2 , Hira L. Nakhasi 4 and Autar K. Mattoo 2 - 5 2 Plant Molecular Biology Laboratory, Beltsville Agricultural Research Center, USDA/ARS, Beltsville, MD 20705, U.S.A. 3 Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21228, U.S.A. 4 Institute of Biologies, FDA, Bethesda, MD 20892, U.S.A. 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-la, lb, lc; 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 com- pared. 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. Key words: Gene expression — Lycopersicon esculentum — Tomato — Wounding. Wounding of plant tissues is accompanied by changes potato leaves (Ryan 1984), and 1-aminocyclopropane-l- in the morphology and biochemistry of the cells (Kahl carboxylate synthase in tomato tissue (Kende and Boiler 1978). Among the major biochemical changes associated 1981). In addition, several PR proteins and their mRNAs with wounding of plants are increases in the activities of en- accumulate in wounded and fungal-elicitor treated tissues, zymes and the levels of proteins, e.g., enzymes of the The induction of some of these proteins takes place within phenyl-propanoid pathway (Cramer et al. 1985), perox- a few hours and is primarily a result of increased gene tran- idases in potato tubers (Borchert 1978), extensin (hydro- scription (Lawton and Lamb 1987). In addition to an in- xyproline-rich protein of cell walls) in carrot storage tissue duction of gene transcription, wounding may also involve (Chrispeels et al. 1974), carboxypeptidase in tomato tissue repression of certain genes, as illustrated by the patatin (Mehta et al. 1990), proteinase inhibitors in tomato and gene family (Logemann et al. 1988). Several of the wound-related genes have been im- Abbreviations: ACP, acyl carrier protein; CPO, cationic plicated in the defense response of a particular plant tissue peroxidase; LS, large subunit; PR, pathogenesis-related; S6PDH, (Ryan 1984, Lawton and Lamb 1987). In fruit tissues, sorbitol-6-phosphate dehydrogenase; D, dalton. however, relatively few wound- and defense-related genes 1 Mention of a trademark or proprietary product does not con- and/or gene products that are regulated by wounding have stitute a guarantee or warranty of the products by the USDA and been identified (Dyer et al. 1989, van Der Straeten et al. does not imply its approval to the exclusion of other products that 1990). Yet, fruits incur extensive damage due to wounding may also be suitable. during growth, harvest, transport and storage, which often 5 Address correspondence to this author at Plant Molecular Biol- results in their susceptibility to pathogens. There have ogy Lab, Building 006, Room 118, USDA/ARS/BARC-W, 10300 been intensive efforts to understand gene regulation during Baltimore Ave, Beltsville, MD 20705-2350, U.S.A. normal fruit ripening (for review see Brady 1987) but 1057 at DigiTop USDA's Digital Desktop Library on July 9, 2015 http://pcp.oxfordjournals.org/ Downloaded from