Subtle proteome differences identified between post-dormant vegetative and floral peach buds

Abstract

Proper development of deciduous tree species, including peach, is accomplished through an annual growth cycle. Freezing avoidance during winter is necessary for tree survival and is achieved by the enclosure of meristems in floral and vegetative buds. To elucidate the role of developmentally regulated protein networks in bud break, proteins of the two bud-types were extracted and analyzed by two-dimensional gel electrophoresis (2-DE). Of the 1107 protein spots that were picked, 475 were identified and annotated assembling the peach bud proteome reference map. The majority of these proteins are involved in stress-response, detoxification, defense, carbohydrate metabolism and energy production. The protein profiles of both bud-types bear high similarity, whereas only 11 proteins were differentially expressed. These proteins were mainly involved in carbon-nitrogen homeostasis/metabolism and certain developmental processes to sustain rapid growth of the newly emerging organs. Among these are enzymes that differentially regulate the levels of H(2)O(2) between floral and vegetative buds, potentially promoting sequential bud-break. Distinct Nucleoside Diphosphate Kinase (NDPK) variants in floral and vegetative buds were detected suggesting the potential role of NDPKs in H(2)O(2)-mediated signaling for post-dormant bud break. This study provides data towards a better understanding of dormancy release and bud break.