Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, China.
School of Life Sciences, Guangzhou University, Guangzhou 510006, China.
J Plant Physiol. 2019 May;236:15-22. doi: 10.1016/j.jplph.2019.02.013. Epub 2019 Feb 27.
Arsenic (As) contamination in agricultural soil can cause phytotoxicity and lead to As accumulation in crops. Rice (Oryza sativa) feeds half of the world's population, but the molecular mechanism of As detoxification is not well understood in rice. In this study, the role of OsNLA1 in arsenate uptake and tolerance in rice was analyzed. OsNLA1 expression was induced in response to As(V) stress. The osnla1 mutant was more sensitive to As(V) stress than those of the wild type (WT). When exposed to As(V), mutation of OsNLA1 resulted in 30% greater As accumulation in roots and shoots of the WT. Although OsPT8 expression was induced after As(V) exposure, the amount of its protein was reduced. Unexpectedly, the osnla1 mutant showed a significant increase in punctate structures of OsPT8-GFP in response to As(V) stress, while the amount of the OsPT8-GFP protein in the osnla1 mutant was greater than in the WT. Combining OsNLA1 mutation with OsPT8 overexpression resulted in As(V) hypersensitivity, As hyperaccumulation, and higher shoot to root ratio of As in rice. These results indicated that OsNLA1 plays an important role in arsenate uptake and tolerance, mainly via regulating the amount of Pi transporters.
砷（As）污染农业土壤会导致植物毒性，并导致作物中砷积累。水稻（Oryza sativa）养活了世界上一半的人口，但水稻中砷解毒的分子机制还不是很清楚。在本研究中，分析了 OsNLA1 在水稻砷酸盐摄取和耐受中的作用。OsNLA1 的表达受到 As(V)胁迫的诱导。与野生型（WT）相比，osnla1 突变体对 As(V)胁迫更为敏感。当暴露于 As(V)时，OsNLA1 的突变导致 WT 根和地上部分的砷积累增加 30%。尽管 OsPT8 的表达在 As(V)暴露后被诱导，但其蛋白的量减少了。出乎意料的是，osnla1 突变体在 As(V)胁迫下显示出 OsPT8-GFP 点状结构的显著增加，而 osnla1 突变体中 OsPT8-GFP 蛋白的量大于 WT。将 OsNLA1 突变与 OsPT8 过表达相结合，导致水稻对 As(V)的敏感性增加、砷超积累以及地上部与根部砷比值升高。这些结果表明，OsNLA1 在砷酸盐摄取和耐受中起着重要作用，主要通过调节磷转运蛋白的数量来实现。
