Negative regulation of cadmium tolerance in Arabidopsis by MMDH2
Negative regulation of cadmium tolerance in Arabidopsis by MMDH2
复制标题
MMDH2对拟南芥镉耐受性的负调控
DOI：
10.1007/s11103-019-00923-w
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发表时间：
2019
影响因子：
5.1
通讯作者：
Shuqing Cao
中科院分区：
文献类型：
--
作者：
Xi Wu;Yangyang Han;Xiangyu Zhu;Alia Shah;Wei Wang;Yibao Sheng;Tingting Fan;Shuqing Cao
MMDH2基因通过调节活性氧（ROS）水平和ROS介导的信号转导，从而影响PDR8的表达，负调控镉耐受。镉（Cd）是对植物毒性最大的重金属之一，其胁迫下植物响应的分子机制尚不清楚。在这里，我们表明，MMDH2，线粒体苹果酸脱氢酶编码基因，参与镉胁迫耐受拟南芥。镉胁迫抑制了MMDH2的表达。MMDH2基因敲减突变体表现出更强的镉耐性，而MMDH2基因过表达株系对镉敏感。在正常和Cd胁迫条件下，mmdh2突变体中H2O2含量均低于野生型。相反，MMDH2过表达株系中H2O2含量较高，且与丙二醛含量呈负相关。此外，表达的PDR8，一个基因编码的镉外排泵，增加和减少的mmdh2突变体和MMDH2过表达线，与较低和较高的镉浓度，分别。这些结果表明，MMDH2基因通过调节活性氧（ROS）水平和ROS介导的信号传导，从而影响PDR8的表达，负调控镉耐受性。
MMDH2 gene negatively regulates Cd tolerance by modulating reactive oxygen species (ROS) levels and the ROS-mediated signaling, thus, affecting the expression of PDR8. The molecular mechanism by which plants respond to stress caused by cadmium (Cd), one of the most toxic heavy metals to plants, is not well understood. Here, we show that MMDH2, a gene encoding mitochondrial malate dehydrogenase, is involved in Cd stress tolerance in Arabidopsis. The expression of MMDH2 was repressed by Cd stress. The mmdh2 knockdown mutants showed enhanced Cd tolerance, while the MMDH2-overexpressing lines were sensitive to Cd. Under normal and Cd stress conditions, lower H2O2levels were detected in mmdh2 mutant plants than in wild-type plants. In contrast, higher H2O2levels were found in MMDH2-overexpressing lines, and they were negatively correlated with malondialdehyde levels. In addition, the expression of the PDR8, a gene encoding a Cd efflux pump, increased and decreased in the mmdh2 mutant and MMDH2-overexpressing lines, in association with lower and higher Cd concentrations, respectively. These results suggest that the MMDH2 gene negatively regulates Cd tolerance by modulating reactive oxygen species (ROS) levels and the ROS-mediated signaling, thus, affecting the expression of PDR8.