Transgenic poplar “NL895” expressing CpFATB gene shows enhanced tolerance to drought stress

Abstract

Acyl-ACP thioesterases are responsible for the export of fatty acids produced by the de novo fatty acid synthesis system from the plastid. A fatty acyl–acyl carrier protein thioesterase (CpFATB) was isolated from a Chimonanthus praecox (linn.) Link. (wintersweet) cDNA library. This gene was subsequently transferred into Populus deltoides CL × P. euramericana CL “NL895” through Agrobacterium tumefaciens-mediated leaf disc transformation. The transgenic plants were confirmed by polymerase chain reaction (PCR) analysis and Southern hybridization. Three positive transgenic lines each with a single T-DNA insertion were obtained. Reverse transcription PCR (RT-PCR) confirmed CpFATB expression in transformed plants after short-term exposure to drought. When exposed to drought stress, transgenic plants showed higher superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity, chlorophyll a content, chlorophyll b content and total chlorophyll content compared with untransformed plants. Malondialdehyde (MDA) content, electric conductivity and net photosynthetic rate of the transgenic plants were lower than untransgenic plants. The results of physiological indices showed that the overexpression of CpFATB in plants exhibited higher drought stress tolerance under drought stress condition compared to the untransformed control plants. Our data further confirmed and highlighted the functions of CpFATB in enhancing plants drought tolerance and may provide a plausible approach to breed plants combating drought stress and enlarging living scope.