敲除DWF4基因提高拟南芥对低温胁迫的抗性

Improvement of cold tolerance by knockout of DWF4 gene in Arabidopsis

以拟南芥类固醇类C22α-羟化酶基因DWF4的T-DNA插入缺失突变体dwf4为研究材料,通过观察突变体在低温胁迫条件下的表型,检测dwf4突变体和野生型在低温胁迫条件下的相对电导率、叶绿素含量、可溶性糖含量、脯氨酸含量、抗冷基因表达量和过氧化物酶基因表达量的区别,探讨了该基因在抗低温胁迫反应过程中的功能。结果表明,敲除DWF4基因能够提高拟南芥对低温胁迫的抗性。dwf4突变体的抗低温胁迫能力一方面源于在低温胁迫下,与野生型相比,dwf4突变体中相对较低的电导率和较高的叶绿素含量,以及更多渗透调节物质可溶性糖和脯氨酸的积累,另一方面源于低温胁迫条件下dwf4突变体中低温胁迫响应的下游基因RD29A及COR47的高表达。结果还表明尽管dwf4突变体中过氧化物含量增加,但是过氧化物酶基因Prx22与Prx698的高表达对过氧化物的毒害起到了很好的抑制作用。说明在拟南芥中DWF4负调控拟南芥对低温胁迫的反应过程。

A T-DNA deletion mutant dwf4 of Arabidopsis was used as material to investigate the role of DWF4 gene in cold tolerance in plants by comparing the phenotypic performance and physioligcal characteristics between dwf4 mutant and wild type seedlings. The dwf4 mutant knockout of DWF4 gene exhibited an increased tolerance to cold ness resulting from lower electrical conductivity, higher chlorophyll content, and higher concentrations of soluble sugar and proline and higher expression levels of RD29A and COR47 compared with wild type. The higher levels of peroxidase genes Prx22 and Prx698 in dwf mutant effectively inhibited the harm caused by the increased reactive oxygen species. Taken together, it was suggested that DWF4 gene might play a negative role in response to cold stress in Arabidopsis.