OsHAC4 is critical for arsenate tolerance and regulates arsenic accumulation in rice
OsHAC4 is critical for arsenate tolerance and regulates arsenic accumulation in rice
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OsHAC4 对于砷耐受性至关重要并调节水稻中的砷积累
DOI：
10.1111/nph.14572
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发表时间：
2017-08-01
期刊：
影响因子：
9.4
通讯作者：
Wu, Zhongchang
中科院分区：
文献类型：
--
作者：
Xu, Jiming;Shi, Shulin;Wu, Zhongchang
土壤砷(As)污染会引起水稻的药害和砷在籽粒中的积累增加。本研究采用正向遗传学方法研究了水稻对砷的耐性和积累机制，获得了一个对砷敏感但对砷不敏感的水稻突变体。基因组重测序和互补试验用于鉴定致病基因。对该基因的功能、表达模式和亚细胞定位进行了研究。OsHAC4是As(V)超敏表型的致病基因。该基因编码一种类似于罗丹丹酶的蛋白，在大肠杆菌中表达时表现为(V)还原酶活性。OsHAC4在根中高表达，并受As(V)诱导。在OsHAC4Pro-GUS转基因植株中，该基因仅在根表皮和外皮中表达。OsHAC4-EGFP定位于胞浆和胞核。OsHAC4突变导致根中As(V)减少，As(III)外流到外源介质中减少，As在地上部的积累显著增加。OsHAC4的过表达增加了水稻对As(V)的耐受性，降低了As在植株中的积累，OsHAC4是一种As(V)还原酶，对As(V)的解毒和控制As在水稻中的积累起关键作用。As(V)还原，As(III)外排是As(V)解毒的重要机制。
Soil contamination with arsenic (As) can cause phytotoxicity and elevated As accumulation in rice grain. Here, we used a forward genetics approach to investigate the mechanism of arsenate (As(V)) tolerance and accumulation in rice.A rice mutant hypersensitive to As(V), but not to As(III), was isolated. Genomic resequencing and complementation tests were used to identify the causal gene. The function of the gene, its expression pattern and subcellular localization were characterized.OsHAC4 is the causal gene for the As(V)-hypersensitive phenotype. The gene encodes a rhodanase-like protein that shows As(V) reductase activity when expressed in Escherichia coli. OsHAC4 was highly expressed in roots and was induced by As(V). In OsHAC4pro-GUS transgenic plants, the gene was expressed exclusively in the root epidermis and exodermis. OsHAC4-eGFP was localized in the cytoplasm and the nucleus. Mutation in OsHAC4 resulted in decreased As(V) reduction in roots, decreased As(III) efflux to the external medium and markedly increased As accumulation in rice shoots. Overexpression of OsHAC4 increased As (V) tolerance and decreased As accumulation in rice plants.OsHAC4 is an As(V) reductase that is critical for As(V) detoxification and for the control of As accumulation in rice. As(V) reduction, followed by As(III) efflux, is an important mechanism of As(V) detoxification.