Drought is one of the abiotic stresses which affects the growth and development of plants, including cotton. The role of stomatal anion channel SLAC1 has been well established in regulating stomatal closure in response to drought stress in several plant species. However, the gene encoding for the main S-type anion channel SLAC1 in cotton has not been identified hence its role in drought stress response remains uncharacterized. In this study, we identified Gh_A08G1582 as the gene encoding for GhSLAC1 in cotton. The gene exhibited abundant expression in leaves and was localized in cell membrane. Furthermore, the expression of GhSLAC1 in Arabidopsis slac1-3 mutants rescued the defective stomatal movement phenotypes of the mutants, pointing to its role in stomata regulation. GhSLAC1 channel was activated by AtOST1 in Xenopus laevis oocytes and showed greater permeability for nitrate than chloride. Further data demonstrated that transgenic cotton lines with silenced GhSLAC1 exhibited obvious leaf wilting phenotype and strong stomatal closure insensitivity under drought stress. Taken together, these results demonstrate that GhSLAC1 is an essential element for stomatal closure in response to drought in cotton.

中文翻译：

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慢阴离子通道 GhSLAC1 对棉花气孔关闭以响应干旱胁迫至关重要

干旱是影响包括棉花在内的植物生长和发育的非生物胁迫之一。气孔阴离子通道 SLAC1 在调节气孔关闭以响应几种植物物种的干旱胁迫方面的作用已得到充分证实。然而，棉花中主要 S 型阴离子通道 SLAC1 的编码基因尚未确定，因此其在干旱胁迫响应中的作用仍未得到表征。在本研究中，我们将 Gh_A08G1582 鉴定为棉花中 GhSLAC1 的编码基因。该基因在叶片中大量表达，定位于细胞膜。此外，GhSLAC1 在拟南芥 slac1-3 突变体中的表达挽救了突变体气孔运动有缺陷的表型，表明其在气孔调节中的作用。GhSLAC1 通道被非洲爪蟾卵母细胞中的 AtOST1 激活，并且对硝酸盐的渗透性高于氯化物。进一步的数据表明，具有沉默 GhSLAC1 的转基因棉花品系在干旱胁迫下表现出明显的叶片萎蔫表型和强烈的气孔关闭不敏感性。总之，这些结果表明 GhSLAC1 是响应棉花干旱的气孔关闭的基本要素。