With the frequent occurrence of extreme natural disasters, unfavorable growth environment is a common phenomenon in the life cycle of plants. In recent years, universal stress proteins (USPs) have attracted extensive attention in the field of plant science for their expression patterns and functional analysis. However, the characterization of the USP family remains unclear in grape. In this study, we identified 30 VvUSPs in the grape genome, which could be divided into three classes according to their encoded protein sequences, and this classification was reflected by the distribution of conserved motifs. Gene duplication analysis demonstrated that segmental duplication was an important pathway in the expansion of the VvUSP family. The expression patterns of 12 VvUSPs were significantly different between tissues, implying they had different functions in various tissues. Cis-acting element and expression analysis showed that most of the promoter regions of VvUSPs contained sequences responsive to hormones and stress elements, especially the promoter region of VIT_16s0013g01920. In conclusion, our findings provide comprehensive information for the further investigation of the genetics and protein functions of the USP gene family in grape.

Suboptimal light stress in grapevines is increasing worldwide with the spread of grapevine cultivation, which can affect grapevine physiology and productivity, such as in Southern China. Abscisic acid (ABA) is an important hormone in plant adaptive responses to abiotic stress, including low light stress. However, ABA signaling pathway genes (APGs) are not well characterized in the grapevine, and little is known of their potentially mitigating role in grapevine growth under weak light stress. Our study aimed to explore the potential role of the ABA signaling pathway in the response of grapevines to suboptimal light conditions. In this study, APGs were identified in the grapevine genome, and the distribution of conserved motifs was shown to reflect their phylogenetic relationships. Gene duplication analysis indicated that segmental duplication was an important driver for gene expansion in the grapevine ABA signaling pathway. Suboptimal conditions of light were shown to seriously affect the growth of grapevine leaves and berries, with the differential regulation of APGs in the grapevine. Our study summarizes the basic characteristics of APGs in grapevine, which can now be examined further for their roles in grapevine’s response to suboptimal light conditions.