寒地冬小麦TaEXPB12同源基因在拟南芥中的遗传转化及功能分析

扩展蛋白（Expansin）是一类具有非水解活性的细胞壁松弛蛋白，参与调控植物的生长发育和胁迫抗性。为探究寒地冬小麦扩展蛋白基因TaEXPB12-A/B/D的功能，本研究将克隆自高抗寒冬小麦品种东农冬麦2号的TaEXPB12-A/B/D三个基因转化到拟南芥中，利用抗性筛选、PCR和Western-blot鉴定，分别获得了过表达TaEXPB12-A/B/D三个基因的转基因拟南芥植株。进一步对转基因拟南芥的生长情况进行观察，并测定低温胁迫下转基因拟南芥的存活率、体内抗氧化酶活性以及丙二醛（MDA）、脯氨酸（Pro）、可溶性糖的含量。结果显示，过表达TaEXPB12-A/B/D三个基因可促进拟南芥根的伸长以及根毛和侧根的生长，且转基因拟南芥的叶宽、叶片数目、株高均显著高于野生型；低温处理后转基因拟南芥体内超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）的活性以及可溶性糖、Pro的含量均维持在较高水平，且MDA的含量较低。以上结果表明，TaEXPB12-A/B/D三个基因的过表达显著促进了转基因拟南芥的生长，并提高了转基因植株在低温胁迫下的存活率。

Genetic Transformation and Functional Analysis of TaEXPB12 Homologous Genes of Winter Wheat in Cold Region

Expansins are cell wall relaxation proteins characterised by non-hydrolytic activity, which are involved in plant growth and stress resistance. To explore the function of the TaEXPB12-A/B/D in winter wheat(Triticum aestivum), in this study, three genes of TaEXPB12-A/B/D which were cloned from Dongnongdongmai 2, a winter wheat variety with high cold resistance were transformed into Arabidopsis. Transgenic Arabidopsis plants overexpressing TaEXPB12-A/B/D were obtained by resistance screening, PCR and Western-blot. The growth of transgenic Arabidopsis was further observed, and the survival rate of transgenic Arabidopsis under low temperature stress, the antioxidant enzyme activities, and the contents of malondialdehyde(MDA), proline(Pro) and soluble sugar were measured. The results showed that the overexpreession of TaEXPB12-A/B/D can promote the elongation of roott and the growth of root hair and lateral root, in addition, leaf width, leaf number and plant height of the transgenic Arabidopsis were significantly higher than those of wild type. After low temperature treatment, the activities of superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) and the contents of soluble sugar and Pro in the transgenic Arabidopsis were maintained at a high level, and the content of MDA was low. The above results showed that the overexpression of TaEXPB12-A/B/D gene significantly promoted the growth of transgenic Arabidopsis and improved the survival rate of the transgenic plants under low temperature stress.