OsPTR7 (OsNPF8.1), a Putative Peptide Transporter in Rice, is Involved in Dimethylarsenate Accumulation in Rice Grain
OsPTR7 (OsNPF8.1), a Putative Peptide Transporter in Rice, is Involved in Dimethylarsenate Accumulation in Rice Grain
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OsPTR7 (OsNPF8.1) 是水稻中一种假定的肽转运蛋白，参与水稻籽粒中二甲基砷酸盐的积累
DOI：
10.1093/pcp/pcx029
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发表时间：
2017-05-01
影响因子：
4.9
通讯作者：
Zhao, Fang-Jie
中科院分区：
文献类型：
--
作者：
Tang, Zhong;Chen, Yi;Zhao, Fang-Jie
对于以大米为主食的人们来说，大米 (Oryza sativa) 是砷 (As) 的主要膳食来源。米粒中含有无机砷和甲基化砷，尤其是二甲基胂酸 (DMA)。 DMA 在植物体内的长距离易位中具有高度的移动性，但其潜在机制仍不清楚。在本研究中，我们发现 OsPTR7 (OsNPF8.1)（一种假定的水稻肽转运蛋白）对于非洲爪蟾卵母细胞中的 DMA 具有渗透性。 OsPTR7-绿色荧光蛋白（GFP）在烟草原生质体中的瞬时表达表明OsPTR7定位于细胞质膜中。实时定量PCR分析表明，OsPTR7在苗期芽中的表达量高于根中的表达量。在开花和灌浆期，OsPTR7 转录本在叶、节 I 和根中丰富。与野生型植物相比，OsPTR7 的敲除或敲低突变体显着减少了 DMA 的根到芽的易位，并且糙米中累积的 As 较少。在田间种植的植物中，DMA 占野生型植物糙米总砷的 35%，但在敲除突变体中检测不到。我们的研究表明，OsPTR7 参与 DMA 的长距离易位，并有助于 DMA 在稻米中的积累。
Rice (Oryza sativa) is a major dietary source of arsenic (As) for the population consuming rice as their staple food. Rice grain contains both inorganic As and methylated As species, especially dimethyarsinate (DMA). DMA is highly mobile in long-distance translocation in plants, but the underlying mechanism remains unknown. In the present study, we showed that OsPTR7 (OsNPF8.1), a putative peptide transporter in rice, was permeable to DMA in Xenopus laevis oocytes. Transient expression of the OsPTR7-green fluorescent protein (GFP) in tobacco protoplasts showed that OsPTR7 was localized in the cell plasma membrane. Quantitative real-time PCR analysis showed that OsPTR7 was more highly expressed in the shoots than in the roots at the seedling stage. At the flowering and grain-filling stage, the OsPTR7 transcript was abundant in the leaves, node I and roots. Knockout or knockdown mutants of OsPTR7 had significantly decreased root to shoot translocation of DMA compared with wild-type plants and accumulated less As in the brown rice. In field-grown plants, DMA accounted for 35% of the total As in the brown rice of wildtype plants but was undetectable in the knockout mutant. Our study demonstrates that OsPTR7 is involved in the long-distance translocation of DMA and contributes to the accumulation of DMA in rice grain.