Genome-wide analysis of peroxidase genes in passion fruit (Passiflora edulis sims.) and their expression patterns induced by root colonization of Piriformospora indica under cold stress

Peroxidases (PODs) have various physiological and biochemical roles in plant growth, development and stress response. The POD genes were identified in various plant species, but in passion fruit has not yet been thoroughly characterized. Here, we discovered 30 putative POD genes from the genome of Passiflora edulis Sims. For further elucidation, comprehensive bioinformatics analysis was utilized to determine the physicochemical properties, gene organization, conserved motifs, gene duplication and phylogenetic relationships of PePOD genes. Most of the POD proteins were predicted to be located in extracellular region. Gene organization and motif analysis showed that the number of exons and motifs in each gene ranged vividly, between 1 and 19, and 7 and 19, respectively. Synteny analysis showed that the segmental duplication played a dynamic role in evolution of POD genes in passion fruit. Likewise, we analysed the expression patterns of PePOD genes in passion fruit seedlings treated with Piriformospora indica under cold stress. The relative expressions of PePOD1, PePOD3, PePOD22, PePOD26 and PePOD29 were noticeably higher in leaves of passion fruit treated with P. indica as compared with untreated ones. The present study provided initial genome-wide identification and characterisation of Class III peroxidases in passion fruit and laid foundation for their further functional analysis.