|Dellapenna, Dean - MICHIGAN STATE UNIVERSITY|
Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 6, 2007
Publication Date: July 7, 2007
Repository URL: http://2007.botanyconference.org/engine/search/index.php?func=detail&
Citation: Sattler, S.E., Dellapenna, D. 2007. Tocopherols modulate defense signaling by blocking the formation of nonenzymatic lipid peroxidation products during germination. American Society of Plant Biologists Annual Meeting. Abstract 1419 Technical Abstract: Tocopherols (Vitamin E) are lipophilic antioxidants that are synthesized by all plants and are particularly abundant in seeds. Two tocopherol deficient mutants, vitamin e (vte) 1 and 2, were used to examine the functions of tocopherols in germinating seedlings. Only vte2 seedlings generated massively elevated levels of nonenzymatic lipid peroxidation products. Global expression profiling using the Affymetrix ATH1 GeneChip showed that several defense-related genes were induced in vte2 relative to wild-type, while there was surprisingly little impact on gene expression in vte1 relative to wild-type in germinating seedlings. The phytoalexin camalexin accumulated to significant levels in vte2 seedlings in the absence of any pathogens. To characterize the function of tocopherols and nonenzymatic lipid peroxidation in defense signaling, a series of double mutants were constructed between vte2 and mutants affecting defense signaling or the generation of nonenzymatic lipid peroxidation products (NahG, SA; coi1, JA; ein2, ethylene; fad, fatty acid desaturation; and pad4). Both biochemical and transcriptional analysis of vte2 and these double mutants demonstrate that nonenzymatic lipid peroxidation products play a significant role in triggering plant defense responses and that tocopherols mitigate these responses. Together these results establish the critical role tocopherols play in controlling nonenzymatic lipid peroxidation during germination and early seedling development.