Genome-wide screening and evolutionary analysis of ZIP (ZRT–IRT like proteins) family in cowpea (Vigna unguiculata L.)

ZIP is one of the most important gene families associated with zinc transportation in plants. Although ZIP genes have been studied in a variety of plant species, yet remain unexplored in cowpea. VuZIPs family was characterized for physiochemical parameters using phytozome. TBtool and CELLO Life were used for detecting domain architecture and sub-cellular location, respectively. Phylogenetic, motif and Gene Structure analysis were carried out using MEGA7, MEME and GSDC, respectively. The genes were mapped on the respective chromosome through PhenoGram Plot while SIAS was used for determining level of homology between 2 genes. The nature and selection pressure on homologous duplicated genes was determined through physical distance and Ka/Ks ratio, respectively. PlantCARE was used for uncovering promoter region while heatmap was generated for expression of VuZIP genes. Sixty ZIP genes, identified across diverse plant species, were divided into five groups. The duplication (paralogs) and speciation (orthologs) events contributed 29% and 14% respectively, to the extension of VuZIP gene family. The VuZIP genes were dispersed on eight different chromosomes. Variation was witnessed in motifs and structure of 14 VuZIP genes associated with five different groups while VuZIP belong to the same group exhibited no differences for these parameters. ABRE and LTRE elements exhibited presence in promoter region of nine and four VuZIP genes, respectively. Purifying selection was determined as driving force for evolution in duplicated genes. VuZIP8 and VuZIP7 exhibited highest expression in leaf and in root, respectively.These results provide valuable information for further functional research of VuZIPs.