Custom Oligo DNA Microarray Analysis for Transcript Profiling of Dormant Buds of Japanese Apricot (Prunus mume)

Bud dormancy in temperate woody perennials is a complex process consisting of three different stages; paradormancy, endodormancy, and ecodormancy. Endodormant buds differ from the other types of dormant buds in that they cannot resume growth under favorable conditions. Because endodormant buds require a certain amount of chilling accumulation for the transition to ecodormancy, genes showing chilling-mediated differential expression patterns are candidates for controlling endodormancy release. We previously performed 454-pyrosequencing and obtained the Japanese apricot (Prunus mume Sieb. et Zucc.) dormant bud ESTs consisting of 28382 contigs and 85247 singletons. Here, we constructed a custom 180-K oligo DNA microarray covering the Japanese apricot dormant bud ESTs that were selected referring the peach (P. persica) genome sequence. Using the microarray, we monitored gene expression changes in vegetative buds of Japanese apricot during chilling exposure. GO based data mining suggested that the genes related to jasmonic acid (JA) biosynthesis and metabolic pathways were significantly up-regulated by chilling while the genes related to stress response was significantly down-regulated. Parametric Analysis of Gene Set Enrichment (PAGE) also detected the significant up-regulation and down-regulation of the genes related to JA biosynthesis and response to temperature stimulus, respectively, during chilling exposure. This study raised the possibility that JA biosynthesis pathway and stress response might be involved in chilling-mediated endodormancy release of Japanese apricot vegetative buds.