A gain-of-function mutation of the MATE family transporter DTX6 confers paraquat resistance in Arabidopsis
A gain-of-function mutation of the MATE family transporter DTX6 confers paraquat resistance in Arabidopsis
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MATE 家族转运蛋白 DTX6 的功能获得性突变赋予拟南芥对百草枯的抗性
DOI：
10.1016/j.molp.2021.09.004
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发表时间：
2021
期刊：
影响因子：
27.5
通讯作者：
Cheng-Bin Xiang
中科院分区：
文献类型：
--
作者：
Jin-Qiu Xia;Tahmina Nazish;Ayesha Javaid;Mohsin Ali;Qian-Qian Liu;Liang Wang;Zheng-Yi Zhang;Zheng-Yi Zhang;Zi-Sheng Zhang;Yi-Jie Huang;Jie Wu;Zhi-Sen Yang;Lin-Feng Sun;Yu-Xing Chen;Cheng-Bin Xiang
百草枯是使用最广泛的非选择性除草剂之一，已引起抗百草枯杂草的出现。然而，百草枯抗性的分子机制尚不完全清楚。在这里，我们报告了拟南芥功能获得突变体pqt15-D，该突变体对百草枯和相应的基因PQT15的抗性显著增强，PQT15编码多药和有毒排泄(Mate)转运体DTX6。DTX6基因+932bp点突变导致G311E氨基酸替换，增强了pqt15-D对百草枯的抗性，而DTX6/PQT15在野生型植物中的过表达也导致了对百草枯的强烈抗性。此外，DTX6和DTX6-D在大肠杆菌中的异源表达显著增强了细菌对百草枯的耐药性。重要的是，DTX6-D的过表达使拟南芥能够耐受4 mM的百草枯，接近商业应用水平。DTX6/PQT15定位于质膜和内膜，通过对分离的原生质体和细菌细胞的百草枯外排试验证明，DTX6/PQT15具有百草枯外排转运体的功能。综上所述，我们的结果表明，DTX6/PQT15是一种外排转运蛋白，通过将百草枯输出到细胞质中来实现对百草枯的抗性。这些发现揭示了高等植物抗百草枯的分子机制，并为转基因抗百草枯作物提供了一个有前途的候选基因。
Paraquat is one of the most widely used nonselective herbicides and has elicited the emergence of paraquat-resistant weeds. However, the molecular mechanisms of paraquat resistance are not completely understood. Here we report the Arabidopsis gain-of-function mutant pqt15-D with significantly enhanced resistance to paraquat and the corresponding gene PQT15, which encodes the Multidrug and Toxic Extrusion (MATE) transporter DTX6. A point mutation at +932 bp in DTX6 causes a G311E amino acid substitution, enhancing the paraquat resistance of pqt15-D, and overexpression of DTX6/PQT15 in the wild-type plants also results in strong paraquat resistance. Moreover, heterologous expression of DTX6 and DTX6-D in Escherichia coli significantly enhances bacterial resistance to paraquat. Importantly, overexpression of DTX6-D enables Arabidopsis plants to tolerate 4 mM paraquat, a near-commercial application level. DTX6/PQT15 is localized in the plasma membrane and endomembrane, and functions as a paraquat efflux transporter as demonstrated by paraquat efflux assays with isolated protoplasts and bacterial cells. Taken together, our results demonstrate that DTX6/PQT15 is an efflux transporter that confers paraquat resistance by exporting paraquat out of the cytosol. These findings reveal a molecular mechanism of paraquat resistance in higher plants and provide a promising candidate gene for engineering paraquat-resistant crops..