| Abstract Detail
Seed Biology You, Young-Sook [1], Plummer, Stacey [1], Leonard, Terry [1], Hayashi, Eiji [1], Still, David W. [1]. Gene expression and QTL analysis of environmentally-induced dormancy in lettuce seeds and the release of dormancy by NO. In lettuce, as in virtually all flowering plants, seeds are dormant upon maturation and a loss of dormancy is required for germination. The establishment, maintenance and loss of seed dormancy are genetically controlled but are also strongly influenced by environmental conditions during and after seed maturation. High temperatures and light quality (far-red light) may induce dormancy in lettuce. The phytohormones ABA and GA inhibit or promote germination, respectively, and their levels can be correlated to environmental conditions. Several compounds, including nitrogen-containing compounds such as nitric oxide (NO), reduce dormancy in a number of species including lettuce. To investigate the role of NO in light and temperature-induced dormancy in lettuce, we imbibed seeds in solutions containing the NO donor sodium nitroprusside (SNP) or the NO scavenger c-PTIO. The lettuce seeds were from a F8 recombinant inbred line of lettuce (Lactuca sativa L.) developed in the Still laboratory. A total of 10 QTL associated with c-PTIO or SNP germination (final germination and speed of germination) were mapped using AFLP markers. In general, NO was not as effective in reducing dormancy as c-PTIO under high temperatures (31.5 ºC continuous red light, 31.5 º C continuous dark) or in conditions where dormancy was induced by far-red light (20 ºC, far-red light followed by dark). Two families were completely dormant under control conditions (20 ºC, continuous red light) but dormancy was largely eliminated when seeds were imbibed in c-PTIO or SNP. To elucidate the signaling pathway by which dormancy was relieved, we examined gene expression of 85 genes associated with ABA and GA synthesis and degradation pathways and light-signaling pathways. Those results will be presented.
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1 - California State Polytechnic University, Pomona, Department of Plant Sciences, 3801 W. Temple Avenue, Building 2, Pomona, California, 91768, U.S.A.
Keywords:
Seed dormancy
phytohormone
QTL
gene expression.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P29020
Abstract ID:2142 |
