The EAR-motif of the Cys2/His2-type zinc finger protein Zat7 plays a key role in the defense response of Arabidopsis to salinity stress
The EAR-motif of the Cys2/His2-type zinc finger protein Zat7 plays a key role in the defense response of Arabidopsis to salinity stress
复制标题
DOI：
10.1074/jbc.m611093200
复制
发表时间：
2007-03-23
影响因子：
4.8
通讯作者：
Mittler, Ron
中科院分区：
文献类型：
--
作者：
Ciftci-Yilmaz, Sultan;Morsy, Mustafa R.;Mittler, Ron
Cyst/His 2型锌指蛋白是一类含有转录抑制子结构域的锌指蛋白，在调节植物对生物和非生物胁迫的防御反应中发挥重要作用。虽然这些蛋白质中的几个的组成型表达显示出增强转基因植物对非生物胁迫的耐受性，但尚不清楚这些蛋白质的EAR基序是否参与该功能。此外，还不清楚在转基因植物中由不同的Cyst/His 2含EAR蛋白诱导的植物生长抑制是否由EAR结构域介导。在这里，我们报告说，组成型表达的Cyst/His 2锌指蛋白Zat 7的转基因拟南芥植物生长受到抑制，更耐盐胁迫。Zat 7的EAR基序的缺失或突变消除了耐盐性而不影响生长抑制。这些结果表明Zat 7的EAR基序直接参与增强转基因植物对盐胁迫的耐受性。相反，EAR基序似乎不参与抑制转基因植物的生长。使用RNAi株系对Zat 7的进一步分析表明，Zat 7在拟南芥中的功能是抑制防御反应的阻遏物。酵母双杂交分析确定了Zat 7和EAR结构域的假定相互作用物，包括WRKY 70和HASTY，一种参与miRNA转运的蛋白质。我们的研究结果表明，Cyst/His 2型锌指蛋白的EAR结构域在拟南芥对非生物胁迫的防御反应中起着关键作用。
Cyst/His2-type zinc finger proteins, which contain the EAR transcriptional repressor domain, are thought to play a key role in regulating the defense response of plants to biotic and abiotic stress conditions. Although constitutive expression of several of these proteins was shown to enhance the tolerance of transgenic plants to abiotic stress, it is not clear whether the EAR-motif of these proteins is involved in this function. In addition, it is not clear whether suppression of plant growth, induced in transgenic plants by different Cyst/His2 EAR-containing proteins, is mediated by the EAR-domain. Here we report that transgenic Arabidopsis plants constitutively expressing the Cyst/His2 zinc finger protein Zat7 have suppressed growth and are more tolerant to salinity stress. A deletion or a mutation of the EAR-motif of Zat7 abolishes salinity tolerance without affecting growth suppression. These results demonstrate that the EAR-motif of Zat7 is directly involved in enhancing the tolerance of transgenic plants to salinity stress. In contrast, the EAR-motif appears not to be involved in suppressing the growth of transgenic plants. Further analysis of Zat7 using RNAi lines suggests that Zat7 functions in Arabidopsis to suppress a repressor of defense responses. A yeast two-hybrid analysis identified putative interactors of Zat7 and the EAR-domain, including WRKY70 and HASTY, a protein involved in miRNA transport. Our findings demonstrate that the EAR-domain of Cyst/His2-type zinc finger proteins plays a key role in the defense response of Arabidopsis to abiotic stresses.