Genome-wide identification of the SOD gene family and expression analysis under drought and salt stress in barley

Superoxide dismutase (SOD) plays a vital role in the removal of active oxygen in plant. In this study, bioinformatics research and expression analysis of SOD gene family under drought and salt stress has been done in barley (Hordeum vulgare L., Hv). Seven SOD genes were identified, including four Cu/Zn-SODs, two Fe-SODs and one Mn-SOD. Those three kinds of SOD genes were distributed in 2, 4 and 7 chromosomes, respectively. Phylogenetic analysis revealed that SODs of barley, rice and Arabidopsis thaliana can be divided into three subfamilies (A-C). Motif analysis founded six conservative motifs. Most SOD genes had relatively conservative intron/exon and motif composition, but the number of intron/exons varied greatly among different genes. Based on RNA-seq data and qRT-PCR analysis of expression changes of barley SOD family gene under stress, HvCSD1, HvCSD4 and HvFSD1 were more valuable for in-depth research due to their significant changes in their expression after stress treatment. These outcomes help to lay the foundation for studying the gene function of barley SOD family and provide the improvement of drought and salt tolerance barley genetic breeding.