Putative role of aquaporins in variable hydraulic conductance of leaves in response to light
Putative role of aquaporins in variable hydraulic conductance of leaves in response to light
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DOI：
10.1104/pp.106.090092
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发表时间：
2007-01-01
期刊：
影响因子：
7.4
通讯作者：
Sakr, Soulaiman
中科院分区：
文献类型：
--
作者：
Cochard, Herve;Venisse, Jean-Stephane;Sakr, Soulaiman
结合核桃（Juglans regia）的分子和生理研究，建立了叶片质膜水通道蛋白在叶片水力传导（K叶）对辐照的响应中的假定作用。本文叙述了光、温对K叶的影响。在黑暗条件下，K-叶低，但增加了400%后，暴露于光。在黑暗的条件下，K-叶值的光暴露的叶子响应温度和0.1 mM放线菌酮治疗。此外，K叶与气孔开度无关。实时荧光定量RT-PCR结果表明，核桃K叶动态与核桃水通道蛋白（JrPIP 2，1和JrPIP 2，2）的转录丰度密切相关。黑暗中的低K叶与JrPIP 2的下调相关，而光照中的高K叶与JrPIP 2的上调相关。K叶和水通道蛋白转录本的光响应是可逆的，并被放线菌酮抑制，表明从头蛋白质合成在此过程中的重要性。我们的研究结果表明，核桃叶片可以迅速改变其水力传导度，并建议这些变化可以解释质膜水通道蛋白的调节。模型模拟表明，核桃叶片水力传导度的变化可能会增加叶片气体交换，同时缓冲叶片水分状况，以响应环境光的波动。
Molecular and physiological studies in walnut (Juglans regia) are combined to establish the putative role of leaf plasma membrane aquaporins in the response of leaf hydraulic conductance (K-leaf) to irradiance. The effects of light and temperature on K-leaf are described. Under dark conditions, K-leaf was low, but increased by 400% upon exposure to light. In contrast to dark conditions, K-leaf values of light-exposed leaves responded to temperature and 0.1 mM cycloheximide treatments. Furthermore, K-leaf was not related to stomatal aperture. Data of real-time reverse transcription-polymerase chain reaction showed that K-leaf dynamics were tightly correlated with the transcript abundance of two walnut aquaporins (JrPIP2,1 and JrPIP2,2). Low K-leaf in the dark was associated with down-regulation, whereas high K-leaf in the light was associated with up-regulation of JrPIP2. Light responses of K-leaf and aquaporin transcripts were reversible and inhibited by cycloheximide, indicating the importance of de novo protein biosynthesis inthisprocess. Our results indicate that walnut leaves can rapidly change their hydraulic conductance and suggest that these changes can be explained by regulation of plasma membrane aquaporins. Model simulation suggests that variable leaf hydraulic conductance in walnut might enhance leaf gas exchanges while buffering leaf water status in response to ambient light fluctuations.