Cross-talk among signal molecules in the regulation of the divinyl ether biosynthetic pathway in tabacco

In tobacco, fungitoxic 9-divinyl ethers (DVEs) produced by the lipoxygenase NtLOX1 and DVE synthase NtDES1 are important for full resistance to pathogens. In this work, the regulation of NtLOX1 and NtDES1 expression by signal molecules related to defense was investigated by RT-qPCR on both genes, and in transgenic plants where GUS expression was driven by the NtLOX1 putative promoter sequence. Methyl jasmonate, ACC and an elicitor molecule were shown to coordinately trigger the DVE pathway; induction was strongly attenuated in the presence of salicylic acid, which seems to act as a negative regulator of 9-DVE production. Dose-dependent activation patterns are currently being checked out by RT-qPCR. Our data suggest that, in tobacco, DVE biosynthesis is cross-regulated by another oxylipin branch (jasmonates), and by hormonal and signal molecules such as ethylene and SA.