Metabolic mechanisms underpinning vegetative bud dormancy release and shoot development in sweet cherry

Few studies have focused on the metabolic characterization of bud dormancy and shoot growth in temperate fruit species, although this is an intresting framework to anticipate adaptation in global climate changes. To examine this issue, two experimental approaches were applied, using sweet cherry (Prunus avium L. cv ‘Grace Star’) bud and shoot tissues. Initially, annual shoots containing vegetative buds that collected at endodormancy and ecodormancy stages were used to compare changes in shoots- and buds-specific metabolic profiles under chamber-controlled conditions. Detailed analysis suggested that primary metabolites, such as arabitol, fucitol and tryptophan were modified in buds from endo- to eco-dormancy. Differences between buds and shoots metabolic fingerprints were also found in various secondary metabolites, including quercetin, glucosides and osmotic-associated metabolites. In order to investigate the mechanism underlying shoot developmental during bud dormancy break, metabolic analysis was also conducted in annual shoots, that were sampled at five distinct bud-related vegetative stages from ecodormancy to fully developed leaf stage under natural orchard conditions. Several amino acids (ornithine, alanine, isoleucine, GABA, asparagine and tryptophan) and classes of secondary metabolites, including anthocyanidins (peonidin-3-O-galactoside), flavonoids (apigenin, isorhamnetin, chrysin and trilobatin) and lignin-related compounds (sinapyl and coniferyl alcohols) were altered across developmental stages. Additionally, nutrient homeostasis was altered during shoot development, as N, P, Ca, Mg, B steady-state level as well as Ca/Mg + K and N/P stoichiometry were significantly changed. This study provides a bud- and shoot-based metabolic framework at different conditions and dormancy stages, thereby helps to understand dormancy release and bud-break in temperate fruit trees