Impacts of CETS genes on tomato fruit ripening

Abstract

In tomato (Solanum lycopersicum), the Solyc03g063100 gene has two alleles with opposite effects: Self pruning 3D (Sp3D), which accelerates flowering, and single flower truss (sft), which inhibits this process. This gene belongs to the CETS family (named after the homolog genes CENTRORADIALIS, TERMINAL FLOWER 1 and SELF-PRUNING, found, respectively in Antirrhinum, Arabidopsis and tomato) (Pnueli et al., 1998), that has a regulatory role in controlling the vegetative/reproductive transition in plants. It is known that auxins and ethylene induce flowering in angiosperms however, the existence of a possible interplay between CETS genes and these hormones remains to be investigated. Studies conducted in our laboratory have demonstrated that homozygous recessive sft tomato plants display ethylene overproduction during the climacteric burst, thereby indicating that SFT/SP3D protein may regulate tomato fruit ethylene biosynthesis pathway. In this sense, this project aims to investigate whether CETS genes play important roles in fine tuning ethylene production in ripening tomato fruits. For this, wild-type, Sp3D and sft fruits will be harvested in distinct ripening stages and analyzed in terms of coloration, respiratory rates, ethylene emission and total activity of 1- aminocyclopropane-1-carboxylic acid oxidase (ACO), whose activity plays a central role in ethylene production. Quality traits such as Brix, vitamin C content, as well as carotenoid profile and total carotenoid content will be analyzed in fully ripe fruits of these three genotypes. Such analyzes may provide valuable information regarding the complex signaling mechanisms underneath the fine tuning of tomato fruit ripening and may also allow the discovery of a new function for CETS genes in plants.