MOLECULAR EXPRESSION OF GENES INVOLVED IN PARTHENOCARPIC FRUIT-SET INTOMATO

To characterize the phenomenon of natural parthenocarpy in tomato (Lyc opersicon esculentum Mill.) two different approaches have been followe d. At a developmental level, the ovary weights of three non-parthenoca rpic lines and three near-isogenic parthenocarpic (pat-2) lines were c ompared. Four developmental stages were considered: flower bud, preant hesis, anthesis and 4 days after anthesis. The parthenocarpic lines di splayed ovary weights higher than their respective non-parthenocarpic lines from preanthesis to 4 days after anthesis. A molecular approach involved comparison of in vitro translation products from flower RNAs taken from the same developmental stages of non-parthenocarpic and nea r-isogenic parthenocarpic (pat-2 and pat-3/pat-4) lines. Analysis by t wo-dimensional polyacrylamide gel electrophoresis showed the different ial expression of a 30-kDa product in parthenocarpic materials from pr eanthesis to anthesis. These results suggest that the physiological an d molecular events responsible for parthenocarpy begin at the preanthe sis stage, before the flower is completely mature and receptive to pol lination. The differential expression of this in vitro translation pro duct in pat-2 and pat-3/pat-4 genotypes also suggests a common or conf luent molecular basis in genetically controlled parthenocarpy.