Aquaporins (AQPs) transport water and other small molecules; however, their precise role in abiotic stress responses is not fully understood. In this study, we cloned and characterized the PIP2 group AQP gene, MaPIP2-7, in banana. MaPIP2-7 expression was upregulated after osmotic (mannitol), cold, and salt treatments. Overexpression of MaPIP2-7 in banana improved tolerance to multiple stresses such as drought, cold, and salt. MaPIP2-7 transgenic plants showed lower levels of malondialdehyde (MDA) and ion leakage (IL), but higher contents of chlorophyll, proline, soluble sugar, and abscisic acid (ABA) compared with wild type (WT) plants under stress and recovery conditions. Additionally, MaPIP2-7 overexpression decreased cellular contents of Na+ and K+ under salt and recovery conditions, and produced an elevated K+/Na+ ratio under recovery conditions. Finally, ABA biosynthetic and responsive genes exhibited higher expression levels in transgenic lines relative to WT under stress conditions. Taken together, our results demonstrate that MaPIP2-7 confers tolerance to drought, cold, and salt stresses by maintaining osmotic balance, reducing membrane injury, and improving ABA levels.

中文翻译：

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水通道蛋白基因MaPIP2-7参与转基因香蕉（Musa acuminata L.）中对干旱，寒冷和盐胁迫的耐受性。

水通道蛋白（AQPs）运输水和其他小分子；然而，它们在非生物应激反应中的确切作用尚不完全清楚。在这项研究中，我们克隆并鉴定了香蕉中的PIP2组AQP基因MaPIP2-7。渗透（甘露醇），冷和盐处理后，MaPIP2-7表达上调。香蕉中MaPIP2-7的过表达提高了对多种胁迫（如干旱，寒冷和盐分）的耐受性。与野生型（WT）植物相比，MaPIP2-7转基因植物与野生型（WT）植物相比，丙二醛（MDA）和离子泄漏（IL）含量较低，但叶绿素，脯氨酸，可溶性糖和脱落酸（ABA）含量较高。 。此外，在盐和恢复条件下，MaPIP2-7过表达会降低Na +和K +的细胞含量，并在回收条件下产生了较高的K + / Na +比。最后，在胁迫条件下，相对于野生型，ABA生物合成和响应基因在转基因品系中表现出更高的表达水平。综上所述，我们的结果表明，MaPIP2-7通过维持渗透压平衡，减少膜损伤和提高ABA水平，赋予了对干旱，寒冷和盐胁迫的耐受性。