Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2009
Publication Date: 4/9/2010
Citation: Foley, M.E., Anderson, J.V., Chao, W.S., Dogramaci, M., Horvath, D.P. 2010. Initial Changes in the Transcriptome of Euphorbia esula Seeds Induced to Germinate with a Combination of Constant and Diurnal Alternating Temperatures. Plant Molecular Biology. 73:131-142. DOI:10.1007/s11103-009-9569-8. Interpretive Summary: Leafy spurge is a noxious perennial weed. To increase our knowledge aimed at biologically-based management, we examined the effect of temperature on seed dormancy and germination and evaluated the global pattern of gene expression in seeds one day after transfer to conditions that facilitate germination. The best conditions for induction of germinate were imbibition at a constant temperature followed by germination at an alternating temperature. Patterns of gene expression suggested a developmental switch from seed development to germination was underway within the first day and plant hormones, sugar, and biological signaling were key regulators for the transition.
Technical Abstract: We investigated transcriptome changes in Euphorbia esula (leafy spurge) seeds with a focus on the effect of constant and diurnal fluctuating temperature on dormancy and germination. Leafy spurge seeds do not germinate when incubated for 21 days at 20°C constant temperatures, but nearly 30% germinate after 21 days under fluctuating temperatures 20:30°C (16:8 h). Incubation at 20°C for 21 followed by 20:30°C resulted in approximately 63% germination in about 10 days. A cDNA microarray representing approximately 22,000 unique sequences was used to profile transcriptome changes in the first day after transfer of seeds from constant to alternating temperature conditions. Functional classification based on MIPS and gene ontology revealed active metabolism including up-regulation of energy, protein synthesis, and signal transduction processes. Down-regulated processes included translation elongation, translation, and some biosynthetic processes. Subnetwork analysis identified genes involved in abscisic acid, sugar, and circadian clock signaling as key regulators of physiological activity in seeds soon after the transfer to alternating conditions.