Modification of the Expression of the Aquaporin ZmPIP2;5 Affects Water Relations and Plant Growth1[OPEN]
Modification of the Expression of the Aquaporin ZmPIP2;5 Affects Water Relations and Plant Growth1[OPEN]
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DOI：
10.1104/pp.19.01183
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发表时间：
2020-04-01
期刊：
影响因子：
7.4
通讯作者：
Chaumont, Francois
中科院分区：
文献类型：
--
作者：
Ding, Lei;Milhiet, Thomas;Chaumont, Francois
玉米质膜水通道蛋白PIP 2;5是玉米（Zea mays）根中表达量最高的一种水通道蛋白，它对根径向水分运动、叶片导水率和植物生长具有重要的调控作用。在这里，我们研究了PIP 2;5表达失调如何影响水的关系和生长使用玉米过表达（OE; B104近交系）或敲除（KO; W22近交系）。与相应的野生型植物相比，水培生长的根的皮层细胞的导水率在PIP 2;5 OE中较高，在PIP 2;5 KO系中较低。虽然与野生型相比，KO品系的全根电导率降低，但在OE植物中没有观察到差异。这一悖论解释使用MECHA水力模型，计算径向流动的水在根部分。该模型提示，细胞的质膜渗透性不是径向均匀的，但PIP 2;5可能是饱和的细胞层与质外体屏障，即内皮层和外皮层，这表明存在的翻译后机制控制PIP的丰度在这些细胞的质膜。在叶水平，其中PIP 2;5基因在野生型植物中弱表达，与野生型植物相比，在PIP 2;5 OE系中的水力传导度较高，而在pip 2;5 KO系中没有观察到差异。叶片伸长速率的时间趋势，作为一个代理的木质部水势，是更快的PIP 2;5 OE植物在轻度胁迫下，但不是在良好的浇水条件下，表明PIP 2;5可能发挥了有益的作用，在植物生长在特定条件下。
The maize plasma membrane PIP2;5 aquaporin plays a role in controlling root radial water movement, leaf hydraulic conductivity, and plant growth.The plasma membrane intrinsic protein PIP2;5 is the most highly expressed aquaporin in maize (Zea mays) roots. Here, we investigated how deregulation of PIP2;5 expression affects water relations and growth using maize overexpression (OE; B104 inbred) or knockout (KO; W22 inbred) lines. The hydraulic conductivity of the cortex cells of roots grown hydroponically was higher in PIP2;5 OE and lower in pip2;5 KO lines compared with the corresponding wild-type plants. While whole-root conductivity decreased in the KO lines compared to the wild type, no difference was observed in OE plants. This paradox was interpreted using the MECHA hydraulic model, which computes the radial flow of water within root sections. The model hints that the plasma membrane permeability of the cells is not radially uniform but that PIP2;5 may be saturated in cell layers with apoplastic barriers, i.e. the endodermis and exodermis, suggesting the presence of posttranslational mechanisms controlling the abundance of PIP in the plasma membrane in these cells. At the leaf level, where the PIP2;5 gene is weakly expressed in wild-type plants, the hydraulic conductance was higher in the PIP2;5 OE lines compared with the wild-type plants, whereas no difference was observed in the pip2;5 KO lines. The temporal trend of leaf elongation rate, used as a proxy for that of xylem water potential, was faster in PIP2;5 OE plants upon mild stress, but not in well-watered conditions, demonstrating that PIP2;5 may play a beneficial role in plant growth under specific conditions.