Abstract
BackgroundGamma-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 korshinskiiγ-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.ResultsCompared 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.ConclusionsThese 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.
Highlights
Gamma-glutamylcysteine synthetase (γ-ECS) is a rate-limiting enzyme in glutathione biosynthesis and plays a key role in plant stress responses
Expression of stomatal development‐related genes was changed after PEG 6000 treatment in C. korshinskii The relative expressions of stomatal developmentrelated genes (CkFAMA, CkSTOMAGEN, CkARF5, and CkAXR3) were evaluated by qRT-PCR (Fig. 2)
The results suggested that auxin signaling may be involved in the stomatal development of C. korshinskii
Summary
Gamma-glutamylcysteine synthetase (γ-ECS) is a rate-limiting enzyme in glutathione biosynthesis and plays a key role in plant stress responses. The Ckγ-ECS overexpressing transgenic Arabidopsis thaliana plants was constructed using the C. korshinskii. The global losses in crop yields due to drought totaled ~$30 billion in the past decade. Drought causes a wide range of changes including reduced leaf sizes, loss of root hairs, low water-use efficiency, and reduced photosynthesis [2,3,4]. The biosynthesis of GSH is tightly regulated by the rate-limiting enzyme gamma-glutamylcysteine synthetase (γ-ECS) [12]. In transgenic Arabidopsis overexpressing γ-ECS without seed vernalization, the level of flowering repressor FLOWERING LOCUS increased, suggesting that floral transition requires redox changes in GSH [17]
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