Abstract
In several plant species, it has been reported that decrease in trienoic fatty acids (TAs) leads to an acquisition of high temperature tolerance. To genetically enhance thermo-tolerance of Cyclamen, we cloned a Cyclamen gene (CpFAD7) encoding a ω-3 fatty acid desaturase, which catalyzes the production of TAs. Targeting of CpFAD7 by RNA interference (RNAi) method yielded transgenic Cyclamen with reduced TA levels (2 mol% of total fatty acids), which were as low as one twenty-fifth of the level in the wild type (WT). Upon exposure to high temperature conditions (38°C, 5 days), the WT severely wilted, whereas the RNAi lines showed no appreciable damage. Some other reports suggested a possibility that the TA depletion increases susceptibility to drought stress. The RNAi lines, however, showed no significant differences from the WT regarding their drought tolerance. The potential involvement of TA-derived electrophiles in the thermo-induced damage of cellular functions will be discussed.
