Pathogenesis-related gene, JcPR-10a from Jatropha curcas exhibit RNase and antifungal activity

The pathogenesis-related proteins have a broad spectrum of roles, ranging from seed germination, development to resistance. The PR-10 is a multigene family differing from other PR proteins in being intracellular, small and acidic with similar 3D structures. We have isolated JcPR-10a cDNA with an ORF of 483 bp from J. curcas, an important biofuel crop grown in the wastelands of India. JcPR-10a gets clustered with dicots in phylogenetic tree. The genomic organisation analysis of JcPR-10a revealed the presence of an intron at conserved 185 bp position. Transcript expression of JcPR-10a was upregulated in response to different stimuli such as NaCl, salicylic acid, methyl jasmonate and M. phaseolina. In response to SA and Macrophomina the transcript was found increased at 48 h, however, in case of NaCl and MeJa a strong induction was observed at 12 h which decreased at 48 h. We first time report the transcript up regulation of PR-10 gene by Macrophomina, a pathogen causing collar rot in Jatropha. The recombinant E. coli cells showed better growth in LB medium supplemented with NaCl, whereas growth of recombinant cells was inhibited in LB medium supplemented with KCl, mannitol, sorbitol, methyl jasmonate and salicylic acid. The JcPR-10a protein was overexpressed in E. coli cells, and was purified to homogeneity, the purified protein exhibited RNase and DNase activity. Furthermore, the protein also showed antifungal activity against Macrophomina, indicating that JcPR-10a can serve as an important candidate to engineer stress tolerance in Jatropha as well as other plants susceptible to collar rot by Macrophomina.