The G protein α-subunit, GPA1, is an integral component of several signaling pathways in plants, including response to abiotic stress. However, the molecular mechanism behind these processes remains largely unknown in the cucumber plant (Cucumis sativus L.). In order to further understand the role of CsGPA1 in cucumber under drought stress, changes in plant growth, physiological parameters, and gene expression of CsAQPs were all measured under water stress induced by polyethylene glycol (PEG) using wild type (WT) and CsGPA1-interference (RNAi) cucumber seedlings. Our results demonstrated that the RNAi plants had lower drought tolerance, displaying seriously withered leaves, lower relative growth rate, lower root-shoot ratio, and lower root activity under drought stress compared to WT plants. Physiological studies indicated that the suppression of CsGPA1 weakened drought stress tolerance due to higher water loss rate in the leaves, higher levels of hydrogen peroxide (H₂O₂), increased malondialdehyde (MDA) content, lower free proline content, lower soluble sugar content, lower soluble protein content, and decreased antioxidant enzyme activities. qRT-PCR analysis demonstrated that the interference of CsGPA1 up-regulated the expression of most AQP genes (except for CsPIP2;3 in leaves) and down-regulated the expression of CsPIP1;2, CsPIP1;4, CsPIP2;1, and CsPIP2;4 in roots under drought stress when compared to WT plants. Our results demonstrated that CsGPA1 could function as a positive regulator in drought stress response by decreasing the accumulation of reactive oxygen species (ROS), improving permeable potentials, and reducing water loss in cucumber plants.

G蛋白α-亚基GPA1是植物中多个信号传导途径（包括对非生物胁迫的响应）的组成部分。但是，这些过程背后的分子机制在黄瓜植物（Cucumis sativus L.）中仍然是未知的。为了进一步了解的作用CsGPA1黄瓜干旱胁迫下，在植物生长，生理参数和基因表达的变化CsAQPs都被使用的野生型（WT）的聚乙二醇（PEG）和诱导的水分胁迫下测量CsGPA1-干扰（RNAi）黄瓜幼苗。我们的研究结果表明，与野生型植物相比，RNAi植物在干旱胁迫下的耐旱性较低，叶片严重枯萎，相对生长速率较低，根冠比较低，根系活力较低。生理研究表明，抑制CsGPA1的原因在于叶片失水率较高，过氧化氢（H ₂ O ₂）含量较高，丙二醛（MDA）含量升高，游离脯氨酸含量降低，可溶性糖含量降低，从而降低了干旱胁迫耐受性，降低可溶性蛋白质含量并降低抗氧化酶活性。qRT-PCR分析表明CsGPA1的干扰与野生型相比，干旱胁迫下根中大多数AQP基因的表达（除CsPIP2; 3除外），而下调CsPIP1; 2，CsPIP1; 4，CsPIP2; 1和CsPIP2; 4的表达植物。我们的研究结果表明，CsGPA1可以通过减少活性氧（ROS）的积累，提高可渗透性并减少黄瓜植株的水分流失而在干旱胁迫响应中发挥积极的调节作用。