The glutaredoxin (GRX) system is one of the important antioxidant systems in plants, involving two key enzymes: GRX and glutathione reductase (GR). The basic bioinformatic characteristics and functions of these enzymes have been extensively studied in various animals and plants. The identification of genes/proteins related to the GRX system in Cardamine hupingshanensis and their expression under selenium stress remains unexplored. In this study, 59 GRX genes and 12 GR genes were identified in C. hupingshanensis . The ChGRX gene family was classified into three types based on phylogenetic analysis and active site characteristics: 10 CPYC-type, 8 CGFS-type, and 41 CC-type. The ChGR gene family was divided into three classes according to phylogenetic analysis: 2 Class Ⅰ, 2 Class Ⅱ, and 8 Class Ⅲ. Under selenium stress, the CC-type ChGRX s in ChGRX family exhibited the highest expression level, followed by the CPYC-type ChGRX s. In the ChGR family, Class Ⅲ genes demonstrated the highest expression level under selenium stress, while Class Ⅰ and Class Ⅱ showed nearly no significant changes. Based on the expression levels under selenium stress, subcellular localization, and intrinsic biochemical properties, we selected four CPYC- and four CC-type ChGRXs for molecular docking exploration. The results suggested that both CPYC- and CC-type ChGRXs may catalyze the deglutathionylation of macromolecular proteins and small molecule ligands, but with distinct catalytic mechanisms among different types. ChGR3- 1 and ChGR3-5 , which showed the highest expression under selenium stress, were selected for molecular docking. The results showed that the key residues of ChGR3-1 included H98, H395, and E394, while those of ChGR3-5 included T69, R73, and K78. These findings indicate that the GRX system in C. hupingshanensis may respond to selenium stress at varying levels. This study presents a comprehensive genome-wide identification and characterization of GRX and GR gene families in C. hupingshanensis , providing a valuable foundation for future functional studies of these critical antioxidant enzymes.
Xue et al. (Fri,) studied this question.