Trehalose Is a nonreduclng dlsaccharlde of glucose that functions as a protectant In the stabilization of blologlcal structures and enhances stress tolerance to abiotic stresses in organisms. We report here the expression of a Grlfola frondosa trehalose synthase （TSase） gene for Improving drought tolerance In sugarcane （Saccharum offlclnarum L.）. The expression of the transgene was under the control of two tandem copies of the CaMV35S promoter and transferred Into sugarcane by Agrobacterium tumefaciens EHA105. The transgenlc plants accumulated high levels of trehalose, up to 8.805-12.863 mg/g fresh weight, whereas It was present at undetectable level in nontransgenlc plants. It has been reported that transgenlc plants transformed with Escherlchla coil TPS （trehalose-6-phosphatesynthase） and/or TPP （trehalose-6-phosphate phosphatase） are severely stunted and have root morphologlc alterations. Interestingly, our transgenlc sugarcane plants had no obvious morphological changes and no growth Inhibition in the field. Trehalose accumulation in 35S-35S：TSase plants resulted In In- creased drought tolerance, as shown by the drought and the drought physiological Indexes, such as the rate of bound water/free water, plasma membrane permeability, malondlaldehyde content, chlorophyll a and b contents, and activity of SOD and POD of the excised leaves. These results suggest that transgenlc plants transformed with the TSase gene can accumulate high levels of trehalose and have enhanced tolerance to drought.
Shu-Zhen ZhangBen-Peng YangCui-Lian FengRu-Kai ChenJing-Ping LuoWen-Wei caiFei-Hu Liu
Trehalose synthase gene (TSase) from Grifola frondosa was transferred into sugarcane (Sac-charum hybrid L.) using Agrobacterium-mediated method to improve sugarcane drought-tolerance. The results indicated that embryogenic callus of sugarcane was sensitive to A. tumefaciens EHA105 strain in the transformation system employed. The high frequency PPT-resistant plants were obtained from transformated with 3 weeks callus after incubation, which reached 4.5% on average. The transgenic plants were confirmed by PCR and Southern analysis. Some transgenic plants showed multiple phenotypic alterations and some plants demonstrated improvement tolerance to osmotic stress.
