过量表达TaNHX2基因提高转基因棉花的抗旱耐盐性

The Overexpression of TaNHX2 Gene Can Improve Salt and Drought Tolerance of Transgenic Cotton

液泡膜Na^(+)/H^(+)反向转运蛋白在调节离子平衡,提高植物耐盐耐旱方面起着重要功能。为了研究液泡膜Na^(+)/H^(+)反向转运蛋白基因TaNHX2在棉花耐盐耐旱中的作用,以晋棉7号为受体,利用农杆菌介导法将克隆自小麦的TaNHX2基因转入棉花愈伤组织,通过组织培养胚状体发生途径获得转基因再生植株。以0.5%卡那霉素对再生苗筛选后,利用PCR和RT-PCR进行分子检测,证实外源基因已导入棉花并正常表达。在温室盆栽条件下,于4片真叶期对转TaNHX2基因棉花及其野生型对照施加NaCl或PEG胁迫处理,处理10天后发现盐胁迫或干旱胁迫显著抑制了棉花光合作用,提高了丙二醛(MDA)含量;转TaNHX2基因棉花的光合速率(Pn)显著高于野生型,MDA含量显著低于野生型;转TaNHX2基因棉花在盐旱胁迫后,叶片和根系中的Na^(+)含量显著低于野生型对照。这些结果说明:在棉花中过量表达TaNHX2基因,盐旱胁迫下可以降低转基因棉花的Na^(+)含量,提高光合速率,降低MDA含量,从而提高转基因棉花的耐盐抗旱能力。

Vacuole-type Na^(+)/H^(+)antiporter can transport Na^(+)into vacuoles,which increase plant salt tolerance by averting the deleterious effects of Na^(+)in the cytosol and maintaining ionic balance.In order to reveal the function of TaNHX2 from wheat in salt tolerance of cotton,the TaNHX2 gene was transferred into the somatic cells of cotton(Jinmian 7)by agrobacterium-mediated transformation technology,and the transformed plants were regenerated through somatic embryogenesis in tissue culture.After selection with 0.5%kanamycin,the kanamycin-resistant regenerated plants were confirmed by PCR and RT-PCR that the TaNHX2 gene was integrated into the genome of cotton and expressed normally.At the four true-leaf stage,transgenic cotton seedlings were treated with different concentrations of NaCl or PEG for 10 days under greenhouse conditions,the photosynthetic rate,MDA content,and Na^(+)content of cotton leaves were determined.The results showed that overexpression of TaNHX2 reduced Na^(+)content in cotton,alleviated ion toxicity and improved salt and drought tolerance of transgenic cotton under salt drought stress.