Glutathione peroxidase genes in ancestral sweet potatoes: genome characterization and bioinformatics analysis

Abstract

Plant glutathione peroxidases (GPXs) consist of non-heme thiol peroxidases that are vital in maintaining hydrogen peroxide homeostasis and regulating plant environmental stress responses. A comparative genomic analysis of the GPX gene family in Ipomoea trifida and I. triloba using their respective genomes was performed. Six GPX genes were identified in each species, which were unevenly located in 4 of the 15 chromosomes of the closest ancestors of the sweet potato genomes (I. trifida and I. triloba). The presence of gene duplications and positive selection were highlighted, suggesting the evolutionary significance of the GPX genes in these species. Based on the phylogenetic analysis, the GPX genes of I. trifida, I. triloba, Arabidopsis thaliana and Oryza sativa can be classified into four groups (I, II, III and IV). The in silico expression analysis in different tissues and development stages revealed tissue-specific expression patterns, hinting at specialized roles for the GPX genes in different plant organs. Nonetheless, the ItfGPX5 and ItbGPX5 genes were highly expressed in most the studied tissues.