转OvDREB2B基因陆地棉鉴定及其对水分渗透胁迫的分析

通过花粉管通道技术,以该实验室自育陆地棉品系TH₁和TH₂为材料,将诸葛菜(Orychophragmus vidaceus)抗逆转录因子OvDREB2B基因构建到植物表达载体后,导入棉花基因组,经卡那霉素筛选和分子鉴定表明目的基因已整合到棉花基因组中并表达。将T₁代转基因植株和受体对照在温室中栽培,待植株生长至四叶一心时,用不同渗透势的PEG-6000水溶液进行渗透胁迫处理,分析探讨转基因植株的抗旱效果及其抗旱机理。结果显示:当渗透势为0和0.5 MPa处理时,转基因植株和对照无明显差异;当渗透势为0.8 MPa和1.1 MPa处理时转基因植株较对照抗旱性明显提高。当渗透势为1.1 MPa处理96 h时,对照植株F_v/F_m降至0.2左右,而转基因植株仍正常生长,F_v/F_m值约为0.51,而且初始荧光（F₀）值、净光合速率（P_n）、胞间CO₂浓度（C_i）、蒸腾速率（T_r）等一系列参数转基因植株都明显优于对照,表明DREB2B基因能够提高棉花对水分胁迫的耐受性。

Identify and Analysis of Transgenic Upland Cotton with OvDREB2B Gene under Osmotic Stress

In this study,two upland cotton lines TH₁ and TH₂ were employed.The anti-retroelement OVDREB2B in Orychophragmus vidaceus was integrated into plant expression vector and the transformation of cotton was conducted by pollen- tube pathway.The results of Kanamycin selection and molecular analysis showed that the transgenic cotton lines with OvDREB2B were obtained.T₁ and receptor plants were grown in greenhouse and treated by a serial of PEG-6000 osmotic potential at seedling stage.The results indicated that the obvious difference induced by different osmotic potential (0 and 0.5 MPa) was not observed in transgenic lines and control plants.However,the transgenic lines exposed to higher osmotic potential (0.8 and 1.1 MPa) displayed a significantly better resistance to drought.Meanwhile,the transgenic plants showed the significantly higher initial fluorescence,net photosynthetic rate,intercellular CO₂ concentration and transpiration rate than did the control plants under 1.1 Mpa condition for 96 h.Based on this fact,DREB2B gene resulted in the development of transgenic lines resistant to drouhgt stress.