College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China.
BMC Plant Biol. 2021 Oct 1;21(1):444. doi: 10.1186/s12870-021-03226-9.
Gamma-glutamylcysteine synthetase (γ-ECS) is a rate-limiting enzyme in glutathione biosynthesis and plays a key role in plant stress responses. In this study, the endogenous expression of the Caragana korshinskii γ-ECS (Ckγ-ECS) gene was induced by PEG 6000-mediated drought stress in the leaves of C. korshinskii. and the Ckγ-ECS overexpressing transgenic Arabidopsis thaliana plants was constructed using the C. korshinskii. isolated γ-ECS.
Compared with the wildtype, the Ckγ-ECS overexpressing plants enhanced the γ-ECS activity, reduced the stomatal density and aperture sizes; they also had higher relative water content, lower water loss, and lower malondialdehyde content. At the same time, the mRNA expression of stomatal development-related gene EPF1 was increased and FAMA and STOMAGEN were decreased. Besides, the expression of auxin-relative signaling genes AXR3 and ARF5 were upregulated.
These changes suggest that transgenic Arabidopsis improved drought tolerance, and Ckγ-ECS may act as a negative regulator in stomatal development by regulating the mRNA expression of EPF1 and STOMAGEN through auxin signaling.
γ-谷氨酰半胱氨酸合成酶（γ-ECS）是谷胱甘肽生物合成的限速酶，在植物应激反应中起着关键作用。在这项研究中，通过 PEG 6000 介导的干旱胁迫诱导锦鸡儿γ-ECS（Ckγ-ECS）基因在锦鸡儿叶片中的内源性表达，并使用分离的 Ckγ-ECS 构建了 Ckγ-ECS 过表达的拟南芥转基因植物。
与野生型相比，Ckγ-ECS 过表达的植株增强了γ-ECS 活性，降低了气孔密度和孔径；它们还具有更高的相对水含量、更低的水分损失和更低的丙二醛含量。同时，气孔发育相关基因 EPF1 的 mRNA 表达增加，而 FAMA 和 STOMAGEN 减少。此外，生长素相关信号基因 AXR3 和 ARF5 的表达上调。
这些变化表明，转基因拟南芥提高了耐旱性，Ckγ-ECS 可能通过生长素信号调节 EPF1 和 STOMAGEN 的 mRNA 表达，作为气孔发育的负调节剂。
