Beyond dormancy: organ-specific gene regulatory netw orks control winter development in peach buds

Bud dormancy in temperate perennials is often described as a stereotyped state of developmental repression triggered by environmental signals. Here, we investigate the development of vegetative buds in Prunus persica during the cold season to assess whether, like flower buds, they remain transcriptionally active. An integrated approach combining cytological analysis, hormone profiling, transcriptome sequencing, co-expression and gene regulatory network (GRN) inference, and in vivo interaction assays was used to compare bud types. Despite similar levels of abscisic acid and gibberellins during chilling accumulation, vegetative and flower buds displayed divergent transcriptional responses. Vegetative buds activated jasmonate- and photoperiod-responsive gene modules, while floral buds were marked by chilling-responsive modules regulated by SHORT VEGETATIVE PHASE 1 (SVP1). Bimolecular fluorescence complementation confirmed specific interactions between SVP1 and DORMANCY-ASSOCIATED MADS-box (DAM) proteins DAM3, DAM5, and DAM6. GRN analysis highlighted bud-specific combinations of DAM and SVP proteins, with DAM5 and DAM6 homodimers predominant in vegetative buds and DAM4 and SVP1/2 heterodimers dominant in flower buds. Our data revise the classical dormancy paradigm: flower and vegetative buds share hormonal trends yet deploy distinct MADS-box combinations to coordinate environment-dependent winter development. The organ-specific DAM/SVP circuitry uncovered here provides a new framework for mechanistic studies on cold mediated peach bud development.