Ribossome-inactivating proteins (RIPs) are found in several plant, fungal, and bacterial species and play an important role in the plant defense system against phytopathogens. The present study aimed to characterize, in silico, the RIP gene and protein family in Jatropha curcas L. Genome annotation in the Jatropha curcas Database (JCDB) enabled the identification of a total of twelve RIP genes. The genes JcRIP1 to JcRIP11 encode curcin, a type I RIP found in physic nut, whereas JcRIP12 is a gene similar to those encoding ricin, a type II RIP present in Ricinus communis L. Light-responsive, MYB, and MYC cis-elements were identified in all promoter regions of the JcRIP genes. To a lesser extent, cis-elements responsive to biotic and abiotic stresses and phytohormones were also detected. JcRIP3 showed the highest expression among the analyzed tissues. In addition to seeds and leaves, RIP gene expression was also observed in stems, roots, and flowers. The number of amino acid residues of physic nut RIP proteins ranged from 291 (JcRIP8) to 551 (JcRIP12). Eight of the twelve JcRIPs exhibited a well-conserved EAAR motif (Glu185-Ala186-Ala187-Arg188). The YFF motif (Tyr99-Phe100-Phe101) was conserved in all JcRIPs analyzed in this study. The results of this work provide knowledge about conditions and locations of JcRIP gene expression, as well as the characteristics of corresponding proteins. This work can contribute to future genetic improvement studies focused on biotic stress, molecular docking analyses aimed at reducing/inhibiting harmfulness, and in vitro tests against phytopathogens.
Oliveira et al. (Thu,) studied this question.