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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (12): 95-105.DOI: 10.11686/cyxb2021477

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Functional analysis of glycine decarboxylase H-protein gene MsGDC-H1 in Medicago sativa

Chun-xue WEI(), Fei HE, Lei XU, Xiao LI, Li-xia ZHANG, Ming-na LI, Lin CHEN, Jun-mei KANG, Qing-chuan YANG, Rui-cai LONG()   

  1. Institute of Animal Sciences,Chinese Academy of Agricultural Sciences,Beijing 100193,China
  • Received:2021-12-22 Revised:2022-03-28 Online:2022-12-20 Published:2022-10-17
  • Contact: Rui-cai LONG

Abstract:

Photorespiration is essential for C3 plants, allowing oxygenated photosynthesis by removing 2-phosphoglycolate. H-protein is one of the key components of glycine decarboxylase (GDC), which converts glycine to serine during photorespiration. The MsGDC-H1 gene was cloned from Medicago sativa. The cloned gene encoded 166 amino acids and had a conserved lipoyl-binding domain and a conserved N6-lipoyllysine site. Phylogenetic analysis showed that MsGDC-H1 was closely related to glycine decarboxylase H-protein (GDC-H) in other dicotyledons. The expression pattern analysis showed that MsGDC-H1 was highly expressed in leaves and was induced by light. To explore the effects of MsGDC-H1 on Arabidopsis thaliana growth, photoinduced stem-leaf specific promoter ST-LS1 and constitutive promoter CaMV 35S were used to drive MsGDC-H1 expression (ST-LS1::MsGDC-H1CaMV 35S:: MsGDC-H1). MsGDC-H1 is heterogeneously expressed in A. thaliana. Biomass, starch and soluble sugar content and photosynthetic rate of overexpressed plants were evaluated. Data analysis showed that CaMV 35S::MsGDC-H1 overexpression (G series) inhibited A. thaliana growth. The starch content of G series was increased by 34%-67% compared with A. thaliana in which ST-LS1::MsGDC-H1 was overexpressed (GS series), and was increased by 7.3%-33.7% compared with wild type (WT) A. thaliana; The soluble sugar content was decreased by 36%-38% compared with GS series and increased by 44.3%-49.7% compared with WT A. thaliana. Compared with WT, GS series plants grew faster, starch content was not significantly different (P>0.05), and soluble sugar content was significantly increased (P<0.05). The experiment results show that MsGDC-H1 plays an important role in regulating photosynthetic rate, carbohydrate synthesis and growth of A. thaliana, and can be used as a candidate gene in genetic engineering breeding to improve alfalfa yield in the future.

Key words: glycine decarboxylase H-protein, yield, photosynthetic rate, carbohydrate content, Arabidopsis thaliana