Genome-wide identification and comparative analysis of the cation proton antiporters family in pear and four other Rosaceae species

The monovalent cation proton antiporters (CPAs) play essential roles in plant nutrition, development, and signal transduction by regulating ion and pH homeostasis of the cell. The CPAs of plants include the Na+/H+ exchanger, K+ efflux antiporter, and cation/H+ exchanger families. However, currently, little is known about the CPA genes in Rosaceae species. In this study, 220 CPA genes were identified from five Rosaceae species (Pyrus bretschneideri, Malus domestica, Prunus persica, Fragaria vesca, and Prunus mume), and 53 of which came from P. bretschneideri. Phylogenetic, structure, collinearity, and gene expression analyses were conducted on the entire CPA genes of pear. Gene expression data showed that 35 and 37 CPA genes were expressed in pear fruit and pollen tubes, respectively. The transcript analysis of some CPA genes under abiotic stress conditions revealed that CPAs may play an important role in pollen tubes growth. The results presented here will be useful in improving understanding of the complexity of the CPA gene family and will promote functional characterization in future studies.