Antisense expression of tomato chloroplast omega-3 fatty acid desaturase gene (LeFAD7) enhances the tomato high-temperature tolerance through reductions of trienoic fatty acids and alterations of physiological parameters

Abstract

We studied how the reductions of trienoic fatty acids (TAs) and increases of dienoic fatty acids (DAs) enhanced hightemperature tolerance in antisense expression of tomato chloroplast omega-3 fatty acid desaturase gene (LeFAD7) transgenic tomato (Lycopersicon esculentum Mill.) plants. In transgenic plants, the content of linolenic acid (18:3) was markedly decreased, while linoleic acid (18:2) was increased correspondingly and the similar changes were observed under high-temperature stress as well. Under high-temperature stress, transgenic plants can maintain a relatively higher level of net photosynthetic rate (P N ) and chlorophyll (Chl) content than that of wild type (WT) plants. A decreased Chl/Carotenoids (xanthophylls and carotenes, Car) ratio and Chl a/b ratio were observed in transgenic plants. Transgenic plants exhibited visible decrease in the relative electrolyte conductivity, higher activities of antioxidative enzymes and lower reactive oxygen species correspondingly than WT. In addition, high-temperature stress for 24 h caused more extensive changes of chloroplast ultrastructure in WT than in transgenic plants. We therefore suggested that the enhancement of high-temperature tolerance in antisense expression of LeFAD7 transgenic plants might be raised from the reduction of TAs and increase of DAs subsequently leading to series of physiological alterations.Additional keywords: high-temperature tolerance; chloroplast omega-3 fatty acid desaturase; Lycopersicon esculentum Mill.; trienoic fatty acids.

Loss of Function of FATTY ACID DESATURASE7 in Tomato Enhances Basal Aphid Resistance in a Salicylate-Dependent Manner

“…To further demonstrate the role of FAD7 in aphid resistance, aphid population growth was measured on a previously described tomato line that has low linolenic acid (C18:3) and high linoleic acid (C18:2) content as a result of antisense silencing of LeFAD7 (Liu et al, 2006(Liu et al, , 2010. Offspring production of potato aphids caged on the antisense line was significantly lower (P = 0.0013) than on the wild-type control (cv L402; Fig.…”