GRAPERIPE · The role of ethylene and of ERF gene regulators in the grapevine berry ripening

Grapevine is one of the most important crops in Europe for production and cultivated area. Ripening is a process that increases flavor and aroma due to the accumulation of anthocyanin and aromatic compounds in berries but it limits transport, store and manipulation. Grape ripening follows a double sigmoid curve characterized for a first volume increase of the berry and a second phase, also called véraison, of accumulation in sugars, softening, coloring and a second increase in size. Grapevine is traditionally classified as a no climacteric fruit supposing an ethylene independent pathway while new recently insights showed a common genetic mechanism between climacteric and no-climacteric fruits where ethylene plays a fundamental role (Lin et al., 2009).The final step in ethylene signaling is regulated by transcription factors called Ethylene Responsive Factors (ERFs) that are involved in fruit ripening and stress processes. It was demonstrated that they bind to a specific GCC-box and modulate genes expression (Fujimoto et al., 2000) and they have been described in tomato, Arabidopsis and other fruits. At FEM, the two interesting ERFs, VvERF045 and VvERF063, have been identified showing the most interesting expression profile correlated to véraison in grape. The first accumulated its transcripts after veráison while the second one showed a clear decrease in expression. Also transgenic plants overexpressing VvERF045 were obtained.The main purpose of the project is a first characterization from a molecular, morphological and biochemical point of view of these transgenic plants to observe the main phenotypical alterations. The research is further focused on the identification of the targets of VvERF045 to better know. We will focus on the most interesting genes resulting for a further association analysis study on a germplasm bank that is present in the research center. This results should help for genetic studies on ripening and breeding purposes.