Plasma membrane intrinsic proteins (PIPs) are known to be major facilitators of the movement of a number of substrates across cell membranes. From a drought-resistant cultivar of Oryza sativa (rice), we isolated an OsPIP1;3 gene single-nucleotide polymorphism (SNP) that is mostly expressed in rice roots and is strongly responsive to drought stress. Immunocytochemistry showed that OsPIP1;3 majorly accumulated on the proximal end of the endodermis and the cell surface around the xylem. Expression of GFP-OsPIP1;3 alone in Xenopus oocytes or rice protoplasts showed OsPIP1;3 mislocalization in the endoplasmic reticulum (ER)-like neighborhood, whereas co-expression of OsPIP2;2 recruited OsPIP1;3 to the plasma membrane and led to a significant enhancement of water permeability in oocytes. Moreover, reconstitution of 10×His-OsPIP1;3 in liposomes demonstrated water channel activity, as revealed by stopped-flow light scattering. Intriguingly, by patch-clamp technique, we detected significant NO3 - conductance of OsPIP1;3 in mammalian cells. To investigate the physiological functions of OsPIP1;3, we ectopically expressed the OsPIP1;3 gene in Nicotiana benthamiana (tobacco). The transgenic tobacco plants exhibited higher photosynthesis rates, root hydraulic conductivity (Lpr ) and water-use efficiency, resulting in a greater biomass and a higher resistance to water deficit than the wild-type did. Further experiments suggested that heterologous expression of OsPIP1;3 in cyanobacterium altered bacterial growth under different conditions of CO2 gas supply. Overall, besides shedding light on the multiple functions played by OsPIP1;3, this work provides insights into the translational value of plant AQPs.

中文翻译：

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水稻质膜内在蛋白（OsPIP1; 3）的异位表达促进植物生长和水分吸收。

已知质膜内在蛋白（PIP）是许多底物跨细胞膜运动的主要促进剂。从水稻的抗旱品种中，我们分离出一个OsPIP1; 3基因单核苷酸多态性（SNP），该基因主要在水稻根部表达，对干旱胁迫反应强烈。免疫细胞化学分析显示，OsPIP1; 3主要积累在真皮的近端和木质部周围的细胞表面。GFP-OsPIP1; 3在非洲爪蟾卵母细胞或水稻原生质体中的单独表达显示OsPIP1; 3在内质网（ER）样邻域中的定位错误，而OsPIP2; 2的共表达将OsPIP1; 3募集到质膜并导致显着提高卵母细胞的透水性。此外，重组10×His-OsPIP1；脂质体中的3表现出水通道活性，如停止流光散射所揭示。有趣的是，通过膜片钳技术，我们在哺乳动物细胞中检测到了明显的NO3-OsPIP1; 3电导。为了研究OsPIP1; 3的生理功能，我们在本生烟草（烟草）中异位表达了OsPIP1; 3基因。转基因烟草植物表现出更高的光合作用率，根系水力传导率（Lpr）和水分利用效率，与野生型相比，具有更大的生物量和更高的耐缺水性。进一步的实验表明，在不同的CO2气体供应条件下，蓝细菌中OsPIP1; 3的异源表达改变了细菌的生长。总体而言，除了着重介绍OsPIP1; 3的多种功能外，