Genome-wide analysis and expression profiling of respiratory burst oxidase homologue gene family in Glycine max

Plant respiratory burst oxidase homologs (Rbohs) are key enzymes that catalyze the generation of reactive oxygen species (ROS) in plants. There is a diverse family of Rboh genes in different plants, mediated a multiplicity of physiological functions. However, there have been limited reports on the characterization of Rboh gene family in soybean. In the present study, seventeen GmRboh genes were identified from the whole-genome sequence of soybean, and these proteins were phylogenetically clustered into five distance subgroups. Comprehensive expression profile analysis provided insights into the soybean-specific functional divergence among members of the Rboh gene family. The expressions patterns of GmRboh genes under biotic/abiotic stress were evaluated based on global gene expression tools and qRT-PCR analysis, and the 'hotspot' genes for development and stress responses were identified. Some duplicate genes were partially redundant, while others showed functional diversity, suggesting the occurrence of sub-functionalization during subsequent evolution. At last, applying diphenylene iodonium (DPI), a classical NADPH oxidase inhibitor, significantly reduced ROS accumulation in soybean roots under abiotic stress, and also influenced the expression of GmRboh genes. Taken together, our results provided a good reference for further functional characterization analysis of members of the Rboh genes in soybean.