KSEF R&D Excellence: Genome Wide Search of Oleate-Responsive Genes in Arabidopsis

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. Loss-of- function mutations in the genes encoding for glycerol-3-phosphate (G3P) acyltransferase, G3P dehydrogenase and a membrane associated w6 desaturase 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. In this study, we propose to search for genes that may be responsive to levels of oleic acid by screening for the oleateresponse- element (ORE) in the UTRs of Arabidopsis genes. A genome wide database search will be followed by comparison of expression patterns of the identified genes in the various mutants. Expression patterns following oleic acid and glycerol treatments will also be studied. Our work will help investigate and better understand the emerging role of fatty acids in the defense response of plants.