Heterotrimeric G proteins consisting of Gα, Gβ and Gγ subunits act as downstream effectors to regulate multiple functions including abiotic stress tolerance. However, the mechanism of Gβ-mediated heat and drought tolerance is yet to be established. To explore the role of Pisum sativum Gβ subunit (PsGβ) in heat and drought stress, transgenic tobacco plants overexpressing (OEs) PsGβ were raised. Transgenic plants showing ectopic expression of PsGβ performed better under heat and drought stress in comparison with vector control plants. The seed germination, relative water content (RWC) and nitric oxide (NO) induction in the guard cells of transgenic plants were significantly higher in contrast to control plants. PsGβ promoter was isolated and several stress-responsive elements were identified. The change in Gβ expression in response to heat, methyl jasmonate (MeJA), abscisic acid (ABA), drought and salt confirms the presence of heat, low temperature and drought-responsive elements in the PsGβ promoter. Also, heat and drought stress caused the release of NO-induced stomatal closure in the leaves of transgenic tobacco plants OEs PsGβ. The better performance of transgenic plant OEs PsGβ is also attributed to the improved photosynthetic parameters as compared with control plants. These findings suggest a role of PsGβ in the signalling pathway leading to NO-induced stomatal closure during heat and drought stress.

中文翻译：

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G 蛋白的豌豆 Gβ 亚基在一氧化氮诱导的气孔关闭中发挥作用，以应对热和干旱胁迫


由 Gα、Gβ 和 Gγ 亚基组成的异三聚体 G 蛋白充当下游效应子，调节多种功能，包括非生物胁迫耐受性。然而，Gβ介导的耐热和耐旱机制尚未确定。为了探索豌豆 Gβ 亚基 (PsGβ) 在热和干旱胁迫中的作用，培育了过表达 (OE) PsGβ 的转基因烟草植物。与载体对照植物相比，显示出 PsGβ 异位表达的转基因植物在热和干旱胁迫下表现更好。与对照植物相比，转基因植物的保卫细胞中的种子发芽率、相对含水量（RWC）和一氧化氮（NO）诱导显着更高。分离出 PsGβ 启动子并鉴定了几个应激反应元件。 Gβ 表达响应热、茉莉酸甲酯 (MeJA)、脱落酸 (ABA)、干旱和盐的变化证实了 PsGβ 启动子中存在热、低温和干旱响应元件。此外，热和干旱胁迫导致转基因烟草植物 OE PsGβ 叶子中 NO 诱导的气孔关闭的释放。与对照植物相比，转基因植物 OE PsGβ 的更好性能也归因于光合参数的改善。这些发现表明 PsGβ 在导致热和干旱胁迫期间 NO 诱导气孔关闭的信号通路中发挥作用。