The MADS‐Box Gene Family Involved in the Regulatory Mechanism of Dormancy and Flowering in Rosaceae Fruit Trees

Abstract

Abstract Temperate perennial fruit tree species enter dormancy in autumn. A prolonged exposure to chilling followed by warm conditions induce dormancy release and bud break. In Rosaceae species, flowering proceeds during dormancy when bud growth is repressed. The SHORT VEGETATIVE PHASE ( SVP )‐clade MADS‐box genes such as DORMANCY‐ASSOCIATED MADS‐boxes ( DAM/SVP s) encode tree bud dormancy regulators. The major effects of DAM/SVPs include growth inhibition and bud break repression through the regulation of plant hormone metabolism in vegetative and floral buds. In addition, the FLOWERING LOCUS C ( FLC ) ‐ clade MADS‐box genes were recently also proposed to encode flowering and dormancy regulators. Apple ( Malus domestica ) FLC may have multifaceted roles in the juvenile–adult phase transition and in the annual development‐dormancy cycle in floral buds. Specifically, in apple, we hypothesize FLC3‐like may facilitate flowering in autumn, whereas an FLC‐like (FLC2) may inhibit bud break, thereby helping floral buds to remain in a quiescent state in winter and preventing an unexpected bud break before the spring. We developed a working model in which abscisic acid, C‐repeat Binding Factor ( CBF ), TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR ( TCP ), micro ribonucleic acid (microRNAs), and epigenetic regulation mediate processes that convert environmental signals into the transcriptional regulation of DAM s and FLC s, thereby ensuring dormancy phase transitions and progression. Finally, possible relationships between MADS‐box genes and dormancy‐associated cellular metabolism are discussed.