Molecular evolution of flowering genes in grapevine

Flowering is a key adaptive trait important for plant fitness and crop production. Recently, using progenies derived from crosses of different varieties, a new QTL for flowering time was mapped in the grapevine genome. We resequenced candidate floral pathway genes located in this QTL from a collection of multiple grape accessions. These genes cooperate to regulate meristem formation and flowering transition. Two of them, FT and SVP, were suggested as major players in plant thermosensory perception. FT is a floral activator that integrates signal inputs from various pathways and SVP controls flowering time by negatively regulating the expression of FT via direct binding. This interaction is proposed as one of the molecular mechanisms evolved by plants to modulate the timing of the developmental transition to flowering under fluctuating temperature conditions. The pattern of linkage disequilibrium and population differentiation at this locus in grapevine may i ndicate that these flowering genes are targets of selection. We investigate possible genotype-phenotype relationships for these candidate genes by applying field observations of flowering time in the core collection recorded during several growing seasons. Our long-term objective is to provide information on the genetic variation of phenological traits and to facilitate choice of grapevine varieties adapted to atmospheric conditions of a specific geographic location