Submitted to: Plant Dormancy Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2009
Publication Date: 6/3/2009
Citation: Foley, M.E., Anderson, J.V., Horvath, D.P., Chao, W.S. 2009. Transcriptome Profiles Associated with Dormancy Status in Seeds of Leafy Spurge (Euphorbia esula). 4th International Symposium on Plant Dormancy Program and Abstracts Book. Page 29.
Technical Abstract: Leafy spurge is an herbaceous perennial weed that reproduces vegetatively through buds and sexually through seeds. Since knowledge about seed dormancy/germination of this species is limited, objectives of this study were to examine effects of constant (21 d at 20°C), alternating (21 d at 20:30°C,16:8 h), and a combination of these temperatures on germination, and elucidate their underlying molecular regulating mechanisms. Seeds were non-germinating at constant temperature, but 28±11% germinated by 21 d under alternating conditions. Germination increased to 62±13% when seeds held at the constant temperature were transferred to the alternating temperature. Even after that treatment, 30% still remained viable but dormant. Microarray analysis was used to compare transcriptomes of dormant, non-germinating, and pre-germinating (constant followed by 3 d alternating) seeds. Over-represented (P value < 0.05) ontologies among genes up-regulated in dormant vs. pre-germinating seeds included hypersensitive, ABA, and various stress responses, and sub-network analysis implicated ABI3, FUS3 and NPR1 as potential active regulatory genes. Down-regulated genes were enriched in ontologies associated with JA and auxin signaling, protein synthesis, and lipase activity, and sub-network analysis intimated activity by JIN1 and ABI4. When comparing dormant to non-germinating seeds, genes associated with hypersensitive responses, photorespiration, and toxic catabolic processes were preferentially expressed in dormant seeds, and identification of ABI4, TOC1, and PIF3 by sub-network analysis suggests alternating temperature likely activated circadian responses. Genes involved in fruit and floral development, chromosome organization and JA responses were down-regulated, and sub-network analysis identified ABI3 and HY5 as potential regulatory effectors. Keywords: Dormancy, germination, leafy spurge, seed, transcriptome analysis, temperature.