Plants experiencing abiotic stress can produce excessive reactive oxygen species (ROS), ultimately impacting the crop growth and yield. Hydrogen peroxide H₂O₂ is a relatively stable active ROS and is mainly scavenged by catalase. In this study, the catalase-encoding E. coli KatE gene was transferred to cotton plants by Agrobacterium-mediated transformation. From almost 100 independent transgenic lines, three transgenic lines were identified that did not display a discernible growth and yield phenotype when grown under well-watered field conditions, but were tolerant to drought under field conditions, resulting in a ~ 25% higher cotton-seed yield. The three lines were analysed under controlled laboratory conditions to explain the drought-dependent phenotype: the transgenic lines displayed drought-inducible EcKatE expression and total catalase activity was only higher than that of the wild type during growth under drought or salinity stress. Furthermore, drought-induced ectopic EcKatE expression increased total SOD and POD activities, decreased H₂O₂ levels and improved photosystem II performance and relative water content. The results show that ectopic EcKatE expression displays an advantage during drought stress, without negatively affecting yield during well-watered field conditions. EcKatE overexpression confers hyper-resistance to drought in cotton and provides improved cotton-seed yield under water-limiting field conditions. And the EcKatE gene might also be a promising drought-resistant gene for improving other crop varieties.

中文翻译：

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在限制水的田间条件下种植时，干旱引起的过氧化氢酶活性增加可提高棉花产量

经历非生物胁迫的植物会产生过多的活性氧 (ROS)，最终影响作物的生长和产量。过氧化氢H ₂ O ₂是一种相对稳定的活性ROS，主要被过氧化氢酶清除。在这项研究中，编码过氧化氢酶的大肠杆菌 KatE基因通过农杆菌转移到棉花植物中。介导的转化。从近 100 个独立的转基因品系中，鉴定出三个转基因品系，它们在水分充足的田间条件下生长时没有表现出明显的生长和产量表型，但在田间条件下耐旱，导致棉籽高约 25%屈服。在受控的实验室条件下分析这三个系以解释干旱依赖性表型：转基因系在干旱或盐胁迫下生长期间表现出干旱诱导的EcKatE表达，并且总过氧化氢酶活性仅高于野生型。此外，干旱诱导的异位EcKatE表达增加了总 SOD 和 POD 活性，降低了 H ₂ O ₂水平和改进的光系统 II 性能和相对含水量。结果表明，异位EcKatE表达在干旱胁迫期间表现出优势，而在水分充足的田间条件下不会对产量产生负面影响。EcKatE过表达赋予棉花对干旱的超抗性，并在限水的田间条件下提高了棉籽产量。而EcKatE基因也可能是一种很有前途的抗旱基因，可用于改良其他作物品种。