Genome-Wide Identification of Wheat USP Gene Family and Functional Dissection of TaUSP85 Involved in Heat Tolerance

Abstract

A collection of conserved proteins known as universal stress protein (USP) is present in a wide range of species, including plants, fungi, bacteria, and animals. USPs are named for their ability to respond to a variety of stress conditions, such as heat stroke, osmotic stress, nutrient limitation, and exposure to toxins or antibiotics. While the USP response to different stress conditions in plants has been reported, little is known about the USP family in wheat (Triticum aestivum L.). In wheat, we identified 88 USP genes distributed across 21 chromosomes classified into four subfamilies. Phylogenetic tree and synteny analysis across multiple species revealed a highly conserved evolution of the USP family between monocots and dicots. Based on comparative analysis of protein domains, gene structure and conserved motifs, TaUSPs showed significant differences among the four subfamilies. Furthermore, expression pattern analysis of TaUSPs showed significant differences among various tissues and under different abiotic stress conditions. We further conducted transformation experiments with the TaUSP85 gene, which significantly enhanced yeast thermotolerance. Silencing of TaUSP85 through VIGS experiments in wheat resulted in significant wilting, decreased chlorophyll content, and increased MDA accumulation compared to control plants. The silenced plant lines had much more ROS accumulation than the control group, as determined by the findings of DAB and NBT staining. The interaction proteins TaUSP1 and TaUSP11 of TaUSP85 were screened by yeast two-hybrid and their interaction relationship was further verified by LCI. Overall, our findings enhance the comprehension of the USP gene family in wheat and provide a valuable resource for further investigation of these genes in wheat and related cereal crops.