Involvements of abscisic acid and MADS-box transcription factors in bud dormancy regulation in fruit trees

Abstract

This research note reviews the physiological and morphological characteristics of winter bud (both vegetative and floral buds) differentiation, development and dormancy during tree dormancy season in Rosaceae fruit trees, to which many important fruit tree crops such as apple (Malus × domestica), peach (Prunus persica), and Japanese apricot (P. mume) belong. Bud dormancy and bud break in woody perennials is thought to be regulated by a number of molecular and metabolic pathways, among which abscisic acid (ABA), SHORT VEGETATIVE PHASE/AGAMOUS LIKE 24 (SVP/AGL24) -clade ［called DORMANCY-ASSOCIATED MADS-box (DAM)］ and FLOWERING LOCUS C (FLC)-clade MADS-box transcription factors have been recently implicated in the regulation of dormancy. ABA-DAM regulon and FLC-like were mainly associated with chilling and heat requirement, respectively, of winter buds for dormancy release and bud break in Rosaceae fruit trees. DAMs and FLCs were responsive to ambient temperature changes where histone modifications mediate. In poplar (Populus spp.), model woody plant, a member of SVP/AGL24-clade gene, called SHORT VEGETATIVE PHASE-LIKE (SVL), mediates short photoperiod-induced ABA-dependent vegetative bud dormancy induction and establishment and acts as a bud break repressor. We will present our own and reported research results on the discovery and physiological roles of PmDAM6, FLC-like, and SVL, in the regulation of bud dormancy and bud break in woody perennials.