Assessment Of The Drought Resistance And Genetic Stability In Sugarcane Mediated With DREB Gene

Drought is one of the most serious problems in sugar production of China.. DREB2B gene was cloned from Erianthus arundinaceum Retz. a wildly related species of sugarcane, in Key Lab of Sugarcane Eco-Physiology& Genetic Improvement, Ministry of Agriculture in 2007, The cloned gene was constructed in an expression vectors driven with stress-inducible promoter RD29A. Six transgenic sugarcane clones mediated with EaDREB2B gene were confirmed in 2008. It was carried out to study genetic stability, drought resistance, yield and quality traits in the T2 generation of these transgenic sugarcane clones. The results showed as fellows:EaDREB2B gene can be stably inherited in the transgenic sugarcane. The EaDREB2B gene could be detected in transgenic sugarcane, but not to be detected in CK using conventional PCR and RT-PCR with specific primers of EaDREB2B gene., which indicated that EaDREB2B gene can stably and efficiently express at DNA level and transcription level.EaDREB2B gene can effectively improve the drought resistance in sugarcane. When the transgenic clones and their receptor cultivar (FN95-1702) were subjected to water stress, the injury rates of plant height in the transgenic clones were lower than those in FN95-1702, especially in transgenic clone DR22, which indicating that transgenic sugarcane clone DR22 has better drought tolerance. The results also showed that MDA content and membrane permeability in transgenic clones subject to water stress increased less than those in FN95-1702, which indicating that the membranes in transgenic clones were not greatly damaged from the lipid peroxidation. Simultaneously, three protective enzymes (SOD,POD,CAT) have positive effect to scavenger the reactive oxygen species in transgenic sugarcane, to reduce membrane lipid peroxidation and to lessen membrane damage, which indicating furtherly that transgenic sugarcane have drought tolerance.Results in soluble sugar content of transgenic sugarcane showed that transgenic clones exposed to water stress increased their soluble sugar content by 1634.764% in DR22, by 1211.893% in DR27 as compared to FN95-1702, which suggesting that EaDREB2B gene may have an effect on osmoregulation of sugarcane to resist water stress.When sugarcane is in sucrose accumulation stage, EaDREB2B gene has changed glucose metabolism mechanism and reduce the speed of sucrose change to other material, it will be benefit to sucrose accumulation. Furthermore, EaDREB2B gene may cause sugarcane enter technical maturing stage earlier.