ELUCIDATION OF THE ROLES OF PROTEIN GLYCOSYLTRANSFERASES SLSPY AND SLSECS IN TOMATO FRUIT DEVELOPMENT

This proposal aims to elucidate the roles of SlSPINDLY (SlSPY, a novel protein O-fucosyltransferase, POFUT) and SlSEC1 and SlSEC2 [O-linked-N-acetylglucosamine (GlcNAc) transferases (OGTs)] in regulating fruit development in tomato (Solanum lycopersicum). Fruit development is strictly regulated in flowering plants. Only upon successful fertilization can an ovary develop into a fruit; this process is called fruit initiation or fruit set. Studies on the model plant tomato and other species have shown that plant hormones play pivotal roles in fruit development. In particular, auxin and gibberellin (GA) are the major hormones that promote fruit initiation and subsequent growth to reach full-size fruit. Upon fertilization, both auxin and GA are produced in young seeds to promote fruit initiation. Importantly, application of either hormone can trigger parthenocarpy (seedless fruit formation without fertilization) in the absence of fertilization, indicating that activation of auxin or GA signaling is required for fruit initiation. Parthenocarpy is a desirable trait for fruit crops because it is preferred by consumers, and it ensures consistent fruit yield in variable environmental conditions that often cause impaired anther/pollen development. Thus, understanding the mechanism of GA- and auxin-induced parthenocarpy will have greater implication in developing climate-resilient crops.The objectives of this project are:1. Elucidate the Roles of SlSPY and SlSECs in Fruit Development by Genetic Analysis2. Determine the Regulatory Mechanism of SlDELLA and SlARFs by SlSPY and SlSECs in Fruit Initiation