Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: September 10, 2007
Publication Date: January 12, 2008
Citation: Chao, W.S., Horvath, D.P., Anderson, J.V., Foley, M.E. 2008. Genomics approach to investigate seasonal dormancy transitions in leafy spurge (Euphorbia esula). Plant and Animal Genome Conference. W77: Bud Dormancy. Technical Abstract: Leafy spurge is a noxious perennial weed that infests range lands in the Northern Great Plains. It is being used as a model to investigate dormancy in underground adventitious buds, i.e., root and crown buds. The leafy spurge EST-database contains 45,314 high-quality sequences which assembled into 23,472 unique sequences representing 19,015 unigenes. Microarrays containing 19,808 leafy spurge and 4,129 cassava DNA probes have been developed to study transcriptome profiles associated with seasonal dormancy transitions. Bud samples collected monthly from August through December over a 5-year period were analyzed. Data obtained from this study identified 999 unigene probes that were differentially expressed (p value>0.005). Our data indicated that many putative cold responsive genes were up-regulated in the fall and winter, while many putative cell cycle genes were down-regulated from summer to winter confirming the fidelity of the array data. MAPMAN analysis indicated that genes involved in metabolic pathways for glycolysis were over-represented among the differentially-expressed genes. In contrast, almost none of the genes involved in the TCA cycle were present among the differentially-expressed genes. Cluster analysis indicated that genes involved in flavonoid biosynthesis were relatively up-regulated during para- and endo-dormancy, but down-regulated during eco-dormancy suggesting that processes involving auxin transport were up-regulated upon re-initiation of growth competence during the transition from endo- to eco-dormancy. Several growth-related genes such as Rb-like protein, GRF5, and AML1 were also up-regulated upon endo-dormancy release. Quantitative real-time PCR was performed to confirm microarray results and investigate gene expression in greater detail.