The RopGEF Gene Family and Their Potential Roles in Responses to Abiotic Stress in Brassica rapa

( ) genes play key roles in plant root and pollen tube growth, phytohormone responses, and abiotic stress responses. genes in have not yet been explored. Here, genes were found to be distributed across eight chromosomes in and were classified into three subfamilies. Promoter sequence analysis of revealed the presence of -elements characteristic of promoters, and these -elements play a role in regulating abiotic stress tolerance and stress-related hormone responses. Organ-specific expression profiling demonstrated that were ubiquitously expressed in all organs, especially the roots, suggesting that they play a role in diverse biological processes. Gene expression analysis revealed that the expression of was significantly up-regulated under osmotic stress and salt stress. RT-qPCR analysis revealed that the expression of was significantly down-regulated under various types of abiotic stress. Protein-protein interaction (PPI) network analysis revealed interactions between RopGEF11, the homolog of , and the VPS34 protein in , as well as interactions between , the homolog of in Arabidopsis, and the ABI1, HAB1, PP2CA, and CPK4 proteins. VPS34, ABI1, HAB1, PP2CA, and CPK4 have previously been shown to confer resistance to unfavorable environments. Overall, our findings suggest that and play significant roles in regulating abiotic stress tolerance. These findings will aid future studies aimed at clarifying the functional characteristics of .