IDENTIFICATION OF TOMATO DIFFERENTIALLY EXPRESSED GENES INVOLVED IN RESPONSE TO WATER DEFICIT

Environmental stress adversely affects plant performance, resulting in significant reduction ofcrop yield and quality worldwide. Increasing aridity of semi-arid regions together with limitedwater resources has led to an exigent necessity for improving crop drought resistance.Elucidating the molecular mechanisms of drought tolerance is critical for increasing cropproduction and quality. Plants do not passively accept environmental stresses, but respond activelythrough perception of stress signals. Responses to water deficit may occur within a few seconds orwithin minutes and hours when a plant withstands the imposed stress, and may arise from eithertolerance or mechanisms that permits avoidance of the situation. In trying to understand responsesto stresses, many genes induced by periods of water deficit have been identified and characterized.Interest has centred on differentially expressed genes, because it has been postulated that inductionof genes will permit adaptation to stresses.We present results of a study on tomato (Solanum lycopersicum L.) differentially expressedgenes induced by water deficit. Two genotypes, selected based on drought tolerance andsusceptibility, were grown in "semi-controlled" conditions (i.e. outdoor and protected from rainfallby transparent plastering covering), with three water stress treatments, and in greenhouse with twowater stress treatments. We investigated the expression of 15 genes candidate to be involved inresponse to water deficit One gene, ERD15, showed a differential expression profile between[0] thetwo genotypes grown under the "semi-controlled" conditions, while 5 genes, including the sameERD15, were differentially expressed in greenhouse.We are currently carrying out a proteomic approach to further analyze genotypic droughtresponsiveness