Is expression pattern of VvLiL, VvMFTianti VvTFLiA linked to IAA/ABA balance in grapevine fruitful buds?

摘要

The reproductive cycle of the grapevine {Vitis vinifera) extends over two consecutive years. Grapevine bud fruitfulness is determined by the number and the size of inflorescence primordia (IP) formed in latent buds during the first year. Many studiesshow that up to 60% of the seasonal variation in yield could be explained by bud fruitfulness. The regulation mechanism of the initiation and differentiation of IP remains little known, but this process seems to be modulated by several molecular regulation factors involved in flowering and embryo development. Some genes involved in flowering process and regulated by auxins (IAA) and abscisic acid (ABA) have also been recently identified in grapevine latent buds. Gene expression analysis of VvLlL, VvMFTland VvTFLlA in different types of fruitful buds (NO, Nl and N2) were realized during their development stages (88 to 159 days after budbreak) of the first year in 'Merlot' cultivar. VvLlL and VvTFLlA were up-regulated in early stages of bud developmentduring the period of the initiation and differentiation of IP. The relative expression of VvMFTl showed significant differences between the three types of buds (NO, Nl and N2) in relation with their development. IAA and ABA contents in latent buds at different stages during the first year were analyzed and correspond to gene expressions: VvTFLlA seems to be activated by IAA, while VvLlL and VvMFTl might be regulated by IAA/ABA balance. These results may support the assumption of the involvement of VvLlL, VvMFTl and VvTFLlA in the regulation of bud fruitfulness and their response to IAA/ABA balance.