Studies on the gene expression of dormant buds of Japanese apricot (Prunus mume)

摘要

Bud dormancy in temperate woody perennial plants is a complex process necessary for plant survival in unfavorable environments. In contrast to the well-known characteristics for some external signals involved in bud dormancy, endogenous internal factors controlling endo-dormancy are poorly understood, partially because of the lack of analysis of molecular aspects of dormancy. In this study, Japanese apricot (Prunus mume) cultivars with high and low chilling requirements for breaking dormancy were used to investigate changes in gene expression in floral and vegetative buds in response to chilling accumulation and development of cold acclimation. The protein induced at a high level in dormant buds in response to chilling accumulation, and suppressed after dormancy break, was identified. Peptide sequencing revealed that this protein encodes dehydrin [the group of D-11 LEA (late embryogenesis-abundant) protein]. Cultivars with different chilling requirements showed a similar dehydrin expression pattern in response to chilling accumulation, implying that dehydrin is associated with the cold and drought tolerance of dormant buds. Subtractive PCR cloning of cDNAs from floral buds of Japanese apricot revealed that dormancy break is accompanied by the induction of cell-cycle related genes. This suggests that the blocking of cell division in buds and its release with accurate timing are involved in regulating dormancy.