Genome-Wide Analysis, Identification, and Transcriptional Profile of the Response to Abiotic Stress of the () Gene Family in Apple.

Purple acid phosphatases (PAPs) play a significant role in plant phosphorus nutrition and can not only release phosphorus from the soil but also regulate the distribution of phosphorus in plants throughout their entire growth and development process. Moreover, members of the PAP protein family exert a more extensive influence on plant mineral homeostasis, developmental processes, and stress responses. Three clusters of purple acid phosphatases, including 31 putative genes, were identified in apples () by searching the Genome Database for Rosaceae. The structure, chromosomal distribution and location, phylogeny, motifs, and cis-acting elements in the gene promoter regions of the gene family are reviewed. These genes exhibit different expression patterns in different tissues. For example, almost all genes are strongly expressed in the roots, except for , , and . Similarily, all were expressed in the leaves while the transcript levels of , , , , , , , and were highest in apple flowers. Overall, the expression of the 31 genes significantly changed in either the roots or leaves following the application of phosphorus and/or drought stress. These results indicate that MdPAP family members play a role in plant adaptation to adverse environments. This work explores the adaptative responses to phosphorus and/or drought conditions in apple and establishes a foundation for an enhanced comprehension of the evolution of PAP families and the exploration of the genes of interest.