Poster: Plant-pathogen interactions

Abs # 567: FA signaling pathway and its role in plant defense

Presenter:	,
Authors	Kachroo, Aardra  (A)   Venugopal, Srivathsa C (A)   Lapchyk, Ludmila  (A)   Hildebrand, David  (B)   Kachroo, Pradeep  (A)
Affiliations:	(A): Department of Plant Pathology, University of Kentucky, Lexington, KY 40546 (B): Department of Agronomy, University of Kentucky, Lexington, KY 40546
Web Site:	http://www.ca.uky.edu/agcollege/plantpathology/PPATHTEST/kachroo/

The salicylic acid (SA)-, jasmonic acid (JA)- and ethylene-mediated plant defense pathways act independently, synergistically as well as antagonistically, thus undergoing extensive cross talk. We have recently shown that a fatty acid (FA) regulated pathway is involved in modulating both the SA- and JA-related responses in Arabidopsis. We identified three genes, all of which participate in the prokaryotic FA pathway and modulate SA and JA pathways in the Arabidopsis desaturase deficient (ssi2) mutant (1). Loss-of-function mutations in the genes encoding for glycerol-3-phosphate (G3P) acyltransferase (2), G3P dehydrogenase (3, 4) and a membrane associated w6 desaturase (2) restore wild-type like phenotypes in the ssi2 plants. Our work with these mutants has demonstrated that complementation of the ssi2-triggered phenotypes involves restoration of oleic acid (18:1) levels in ssi2 plants. This suggests that 18:1 or an 18:1 derived molecule(s) acts as the signal for restoring cross-talk between the SA and JA-related pathways. Our results show that 18:1 levels in plastids are regulated via acylation with G3P and a balance between G3P and 18:1 is critical for the regulation of SA- and JA-mediated signaling pathways. 1 Kachroo, P., Shanklin, J., Shah, J., Whittle, E.J. and Klessig, D.F. 2001. Proc. Natl. Acad. Sci. USA. 98:9448-9453. 2. Kachroo, A., Lapchyk, L., Fukushigae, H., Hildebrand, D., Klessig, D., Kachroo, P. (2003) Plant Cell 15, 2952-2965. 3. Kachroo, P., Kachroo, A., Lapchyk, L., Hildebrand D., Klessig, D. (2003) Mol. Plant-Microbe Interact. 11,1022-1029. 4. Kachroo, A., Srivathsa C. V., Lapchyk, L., Falcone, D., Hildebrand, D., Kachroo, P. (2004) Proc. Natl. Acad. Sci. USA. In press.