SitkaSpruce_FB3-425_Bark_PissodesStrobi_Herbivory

Based on the generation of ESTs, we developed a spruce cDNA microarray composed of 21,843 cDNA elements selected from 12 cDNA libraries representing developmental stages of xylem, phloem, bark and roots, as well as elicitor-treated bark. Clones on the array were selected from a CAP3 assembly of 50,770 hq 3’ ESTs, and were carefully chosen to represent a minimally redundant gene set. Using this array we examined global changes in the transcriptome of Sitka spruce attacked for two days by stem-boring white pine weevils. Differentially expressed genes were determined using three criteria: fold-change between weevil-treated and untreated control > 1.5-fold, P value < 0.05 and Q value < 0.05. After 48 h of weevil feeding, 1,857 (8.5%) microarray elements identified transcripts as up-regulated, compared to 1,374 (6.3%) down-regulated. Keywords: Stress response Eight hybridizations were performed comparing weevil-treated bark after 48 hours of continuous feeding and untreated control bark harvested at the same time. RNA isolated from each of the four individual weevil-treated trees was compared directly against the four individual untreated control trees using two hybridizations with a dye flip for each tree pair.