Genome-wide analysis of purple acid phosphatase (PAP) family proteins in Jatropha curcas L.

Purple acid phosphatase (PAP) family genes play a crucial role in the phosphorus (P) foraging and recycling. There are 25 putative Jatropha curcas PAP genes (JcrPAP) were identified and classified into three groups based on their molecular weights. Subcellular localization prediction indicated that most of the JcrPAPs were localized to secretory pathway. Several PAPs possess signal peptide motifs and varied numbers of N-glycosylation and transmembrane helix motifs. JcrPAP proteins have 3-5 active pocket sites comprising 1 to 11 binding residues which interact with different ligands such as iron (Fe), N-acetyl l-d-Glucosamine (NAG), zinc (Zn) and manganese (Mn). The core structure of the predicted JcrPap28 was similar to the Ipomoea batatas Pap protein. Most of the JcrPAP genes showed higher expression in the root tissues compared to stem and leaf tissues. Several JcrPAP genes were upregulated under low phosphorus conditions. JcrPAP genes such as JcrPap26b, JcrPap27b, and JcrPap28 have shown multifold induction in low phosphorus treated plants which suggest that these genes might be involved in phosphorus metabolism. The present study provided the structural variations and expression regulation of JcrPAP genes in the economically viable biodiesel crop and it would be helpful for the crop improvement under phosphorus limiting conditions.