冬小麦膨胀素基因TaEXPB8、TaEXPB10的克隆及低温表达分析

以冬小麦强抗寒品种东农冬麦1号为试验材料,从其根中克隆膨胀素基因TaEXPB8、TaEXPB10,并分析其在低温条件下的表达情况,为研究膨胀素基因与植物抗寒性之间的关系奠定基础。结果表明,在冬小麦强抗寒品种东农冬麦1号根中克隆得到膨胀素基因TaEXPB8、TaEXPB10,二者分别编码273、271个氨基酸,二者序列与Gen Bank上公布的序列同源性分别达到99.2%、99.6%。4℃、-10℃和-20℃的低温胁迫处理均可诱导TaEXPB8、TaEXPB10基因在冬小麦强抗寒品种东农冬麦1号根中表达,尤其是TaEXPB10基因,其受诱导程度高于TaEXPB8;两基因在低抗寒品种济麦22号中总体上不受诱导,甚至受到抑制。综合比较发现,4℃、-10℃和-20℃低温胁迫下,TaEXPB8、TaEXPB10基因在强抗寒品种东农冬麦1号中的表达量均明显高于低抗寒品种济麦22号。据此推测膨胀素基因TaEXPB8、TaEXPB10与冬小麦根系的低温胁迫耐受能力具有重要的相关性,有助于进一步深入了解冬小麦根系的抗寒机制。

Cloning of TaEXPB8 and TaEXPB10 in Winter Wheat and Their Expression Analysis under Low Temperature Condition

The cold-resistant winter wheat variety Dongnongdongmai No. 1 was used as experimental ma-terial. The expansin genes TaEXPB8 and TaEXPB10 were cloned from its roots,and their expression pro-files were analyzed under low temperature conditions,so as to lay a foundation for study of the relationship between expansin genes expression and the plant cold resistance. The results showed that the expansin genes TaEXPB8 and TaEXPB10 were cloned from cold-resistant winter wheat variety Dongnongdongmai No. 1,which coded 273 and 271 amino acids,respectively. In addition,they shared 99. 2% and 99. 6%homology separately with the published sequence in GenBank. Besides,4 ℃,-10 ℃ and -20 ℃ could induce the expression of TaEXPB8 and TaEXPB10 in roots of Dongnongdongmai No. 1. Especially for TaEXPB10,it had higher inducing level than TaEXPB8. However,these two genes were not induced in Ji-mai No. 22 ( cold susceptible variety) on a whole,even were suppressed. Taken together,we found that under 4 ℃,-10 ℃ and -20 ℃,the expression level of TaEXPB8 and TaEXPB10 in Dongnongdongmai No. 1 (cold resistant variety) were all significantly higher than that in Jimai No. 22(cold susceptible vari-ety) . Thus,it had been postulated that the expansin genes TaEXPB8 and TaEXPB10 had great relevance with low temperature stress tolerance ability of the roots of Dongnongdongmai No. 1. It also provided fur-ther understanding on the cold resistance mechanism in winter wheat root system.