Drought and high salinity are two major abiotic stresses that significantly affect agricultural crop productivity worldwide. Annexins are a multigene family that plays an essential role in plant stress responses and various cellular processes. Here, the AnnSp2 gene was cloned from drought-resistant wild tomato (Solanum pennellii) and functionally characterized in cultivated tomato. AnnSp2 protein was localized in the nucleus and had higher expression in leave, flower and fruit. It was induced by several phytohormones and some abiotic stresses. Tomato plants overexpressing AnnSp2 had increased tolerance to drought and salt stress, as determined by analysis of various physiological parameters. AnnSp2-transgenic plants were less sensitive to ABA during the seed germination and seedling stages. However, under drought stress, the ABA content significantly increased in the AnnSp2-overexpressing plants, inducing stomatal closure and reducing water loss, which underlay the plants' enhanced stress tolerance. Furthermore, scavenging reactive oxygen species (ROS), higher total chlorophyll content, lower lipid peroxidation levels, increased peroxidase activities (including APX, CAT and SOD) and higher levels of proline were observed in AnnSp2-overexpressing plants. These results indicate that overexpression of AnnSp2 in transgenic tomato improves salt and drought tolerance through ABA synthesis and the elimination of ROS.

中文翻译：

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膜联蛋白基因AnnSp2的过表达通过调节ABA合成并清除番茄中的ROS来增强干旱和盐分耐受性。

干旱和高盐度是严重影响全球农业作物生产力的两个主要非生物胁迫。膜联蛋白是一个多基因家族，在植物胁迫反应和各种细胞过程中起着至关重要的作用。在这里，AnnSp2基因是从抗旱野生番茄（Solanum pennellii）中克隆的，并在栽培番茄中进行了功能鉴定。AnnSp2蛋白位于细胞核中，在叶，花和果实中有较高的表达。它是由几种植物激素和一些非生物胁迫引起的。通过分析各种生理参数可以确定，过表达AnnSp2的番茄植株对干旱和盐胁迫的耐受性增强。在种子萌发和幼苗阶段，AnnSp2转基因植物对ABA的敏感性较低。但是，在干旱的压力下，过量表达AnnSp2的植物中ABA含量显着增加，诱导气孔关闭并减少水分流失，这是植物增强胁迫耐受性的基础。此外，在过表达AnnSp2的植物中观察到了清除活性氧（ROS），较高的总叶绿素含量，较低的脂质过氧化水平，增加的过氧化物酶活性（包括APX，CAT和SOD）和脯氨酸的水平。这些结果表明，转基因番茄中AnnSp2的过表达通过ABA合成和消除ROS改善了耐盐和耐旱性。在过表达AnnSp2的植物中观察到较低的脂质过氧化水平，增加的过氧化物酶活性（包括APX，CAT和SOD）和较高的脯氨酸水平。这些结果表明，转基因番茄中AnnSp2的过表达通过ABA合成和消除ROS改善了耐盐和耐旱性。在过表达AnnSp2的植物中观察到较低的脂质过氧化水平，增加的过氧化物酶活性（包括APX，CAT和SOD）和较高的脯氨酸水平。这些结果表明，转基因番茄中AnnSp2的过表达通过ABA合成和消除ROS改善了耐盐和耐旱性。