新疆野苹果MsDREBA6提高植物抗旱性的作用初探

为探明脱水响应元件(DREBs)提高植物抗旱性的作用机制,以新疆野苹果(Malus sieversii Roem.)组培苗为试材,采用实时荧光定量PCR(qRT-PCR)分析MsDREBA6在干旱胁迫下的时空表达特性,并结合转基因拟南芥分析了过表达MsDREBA6对根系发育的影响。结果表明,MsDREBA6在新疆野苹果根系中表达水平最高,且受干旱诱导表达。过表达MsDREBA6拟南芥抗旱性显著增强,主根长度虽略短于野生型,但侧根密度和侧根长度均显著大于野生型;且转基因植株根系内源生长素(IAA)含量升高,玉米素核苷(ZR)含量略有降低,致使IAA/ZR显著提高。进一步分析表明,转基因拟南芥根系中参与侧根发育的生长素相关基因表达显著上调,而细胞分裂素生物合成受到抑制。由此推测,MsDREBA6可以通过调控一系列生长素和细胞分裂素相关基因表达变化,改变根系中IAA/ZR平衡,从而促进侧根发育以提高植物的抗旱性。

Initial exploration of MsDREBA6 to increase the drought resistance of Malus sieversii Roem.

This study aims to understand the role of dehydration responsive element binding protein(DREBs) in plant drought resistance.With Malus sieversii Roem.as research materials,the time-space characteristics of MsDREBA6 expression was analyzed by quantitative real-time PCR(qRT-PCR).The effects of MsDREBA6 on root development were analyzed with MsDREBA6-OE Arabidopsis thaliana.The results showed that the expression level of MsDREBA6 was highest in roots of M.sieversii Roem.,and was induced by drought treatment.Overexpression of MsDREBA6 enhanced the drought resistance of Arabidopsis thaliana plants significantly. MsDREBA6- OE transgenic plants exhibited slightly decreased the primary root length,but remarkably increased lateral root density and length than wild type plants.The content of free IAA in roots of MsDREBA6 transgenic plants was significantly higher than that in WT,and ZR was slightly lower,hence the ratio of IAA/ZR was increased significantly.Further analysis showed that the auxin-related genes,which are involved in lateral root development,increased obviously.However,the biosynthesis of cytokinins was inhibited slightly. MsDREBA6 could change the balance of IAA/ZR in roots by regulating the expression pattern of auxin and cytokinin related genes,and promote the lateral root development,to improve the drought resistance of plants.