Glutaredoxins (GRXs) are small oxidoreductases that play a crucial role in response to abiotic stress. Although the GRX gene family has been characterized in several species, the knowledge of their evolution relationship, diversification and function in grape are still limited. In this study, 32 VvGRX genes were identified and clustered into CC-, CGFS-, GRL- and CPYC-type categories. The structure and motifs of VvGRXs were similar in genes clustered into close branches, indicating highly conserved during the evolutional process. Cis-acting elements mainly were involved in stress response and hormone regulation. Tissue-specific expression showed that VvGRXs were differentially expressed in different grape tissues. qRT-PCR indicated that VvGRX28 expression could actively be induced by cold stress. Furthermore, VvGRX28 was functionally characterized and cloned to verify the cold tolerance function. Through Agrobacterium-mediating to overexpress and interfere VvGRX28, the result demonstrated that the VvGRX28 overexpression could enhance the content of proline (Pro), soluble sugar (SS), glutathione (GSH) and peroxidase (POD) activities, and reduced the content of malondialdehyde (MDA) and hydrogen peroxide (H2O2), and upregulated the expression of ICE, CBF and COR in Arabidopsis thaliana and grape callus, while exhibiting an opposite trend after RNAi. VvZNF10, as the interaction protein of VvGRX28, overexpression and co-transformation with VvGRX28 could improve the cold tolerance in grape callus. The results demonstrate that VvGRX28 is a positive regulator to enhance cold tolerance interacting with VvZNF10 in grape. Collectively, this study provides a comprehensive analysis of the VvGRX gene family, offering novel insights into the regulation mechanism of VvGRX28 under cold stress in grape.
Nai et al. (Mon,) studied this question.