Extensive transcriptome changes during vegetative bud dormancy in Populus

We investigated differential gene expression patterns in Populus vegetative buds between paradormant, endodormant, and ecodormant dormancy states. Our primary objectives were to (1) identify which individual genes, biological processes, molecular functions, and regulatory pathways were differentially expressed among dormancy states, (2) classify the differentially expressed genes into contrasting gene expression patterns, and (3) identify cis-acting elements associated with each gene expression group. For more details consult Howe et al. (Frontiers in Plant Science, 2015, pending). Nimblegen whole genome microarrays (n=10 arrays) were hybridized with total RNA isolated from axillary buds collected on five dates between August and March. On each date, RNA was isolated from two P. trichocarpa trees (clone Nisqually-1) growing in the field. After cDNA synthesis and labeling, the samples were sent to NimbleGen for fragmentation, hybridization, and detection. The Nimblegen microarray was designed for the Populus v1.0 genome assembly, but for data analysis, the 60-mer probes were reassigned to the Populus v3.0 gene models.