Abstract The plant-specific tau-class of glutathione S-transferase (GSTU) has high stress-inducing expression characteristics that can play an important protective role in plant tolerance to different environmental stresses. To explore the mechanisms underlying submergence and reoxygenation tolerance in soybean plants, the transcriptomic analysis of leaves under submergence was firstly performed using the highly submergence-tolerant G. soja accession (P18B) and the submergence-sensitive G. max cultivar (KF1), and two potential submergence-responsive GSTU genes, GsGSTU24 and GsGSTU42, were identified. Their physiological functions in tolerance to submergence and subsequent desubmergence were compared in GsGSTU24- and GsGSTU42-overexpressing hairy root composite soybean plants or transgenic Arabidopsis plants. The results showed that, overexpression of GsGSTU24 or GsGSTU42 could alleviate submergence and subsequent desubmergence stress on soybean hairy root composite plants or transgenic A. thaliana seedlings by enhancing antioxidant ability for leaf ROS detoxification or homeostasis reestablishment, and by improving the chlorophyll content and quantum efficiency of chlorophyll fluorescence (Fv/Fm) for maintenance of leaf photosynthetic capacity. Our results further indicate that, the genes GsGSTU42 or GsGSTU24 from high submergence-tolerant G. soja P18B could be considered as the vital submergence tolerance determinants for utilization in molecular breeding designs for flooding-tolerant crop improvement in the future.

中文翻译：

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淹水胁迫下大豆和G.max幼苗的转录组学分析及GsGSTU24和GsGSTU42基因的功能表征

摘要 植物特异性tau 类谷胱甘肽S-转移酶(GSTU) 具有高胁迫诱导表达特性，可在植物对不同环境胁迫的耐受性中发挥重要保护作用。为了探索大豆植株耐水和再氧合的潜在机制，首先使用高度耐水的大豆 G. 种质 (P18B) 和对浸水敏感的 G. max 品种 (KF1) 进行了水下叶片的转录组学分析，和确定了两个潜在的淹没响应 GSTU 基因，GsGSTU24 和 GsGSTU42。在过表达 GsGSTU24 和 GsGSTU42 的毛根复合大豆植物或转基因拟南芥植物中，比较了它们在耐淹没和随后的去淹没方面的生理功能。结果表明，GsGSTU24 或 GsGSTU42 的过表达可以通过增强叶片 ROS 解毒或体内平衡重建的抗氧化能力，以及通过提高叶绿素含量和叶绿素荧光量子效率（Fv /Fm) 用于维持叶片光合能力。我们的研究结果进一步表明，来自高耐淹性大豆 P18B 的基因 GsGSTU42 或 GsGSTU24 可被认为是未来耐淹作物改良分子育种设计的重要耐淹性决定因素。拟南芥幼苗通过增强叶片 ROS 解毒或稳态重建的抗氧化能力，以及通过提高叶绿素含量和叶绿素荧光量子效率 (Fv/Fm) 来维持叶片光合能力。我们的研究结果进一步表明，来自高耐淹性大豆 P18B 的基因 GsGSTU42 或 GsGSTU24 可被认为是未来耐淹作物改良分子育种设计的重要耐淹性决定因素。拟南芥幼苗通过增强叶片 ROS 解毒或稳态重建的抗氧化能力，以及通过提高叶绿素含量和叶绿素荧光量子效率 (Fv/Fm) 来维持叶片光合能力。我们的研究结果进一步表明，来自高耐淹性大豆 P18B 的基因 GsGSTU42 或 GsGSTU24 可被认为是未来耐淹作物改良分子育种设计的重要耐淹性决定因素。