Genome-wide identification and protein interactions of the TIFY family in the bioenergy plant Jatropha curcas L.

Abstract

Jatropha curcas L. is an important energy crop whose growth is affected by abiotic stress. TIFY proteins regulate plant growth and respond to adverse conditions in higher plants. However, little information is available regarding the functions of the TIFY family genes in J. curcas. In this research, 14 members of the JcTIFY family were identified in J. curcas at the genome-wide level. These members belong to four subfamilies: jasmonate-ZIM-domain (JAZ), ZIM/ZIM-like, PEAPOD, and TIFY, and they are distributed across seven linkage groups. The TIFY proteins, consisting of 135–458 amino acids, are all hydrophilic and are predicted to be located in the nucleus. Although members of the same branch have different exon-intron structures, they share similar conserved domains and motif compositions. Protein interaction predictions indicate that TIFY proteins can form dimers and are involved in the jasmonic acid and ethylene signaling pathways. The role of TIFY in the growth of J. curcas was demonstrated by the analysis of cis-acting elements and expression of TIFY under various conditions and tissues. Furthermore, RT-qPCR analysis revealed that chilling stress and methyl jasmonate significantly induced the expression of JcJAZs, particularly JcTIFY5B. Yeast two-hybrid analysis revealed clear interactions between JcJAZs. Luciferase complementation and yeast two-hybrid assays demonstrated that JcTIFY10 formed a homodimer both in vivo and in vitro. JcJAZ proteins can form heterodimers with other proteins of the same family, and some proteins can form homodimers via the TIFY domain. The subcellular localization of JcTIFY5A and JcTIFY10 was in the nucleus, while JcTIFY9 was found in both the cytoplasm and nucleus. These results provide significant insights into the TIFY gene-mediated abiotic stress response and plant hormone signal transduction events in J. curcas.