First Expressed TFome of Physic Nut (Jatropha curcas L.) After Salt Stimulus

Abstract

Physic nut (Jatropha curcas L.), a small oleaginous tree spontaneously occurring in arid and semi-arid tropical regions, is a sustainable and renewable energy source for biodiesel. However, the J. curcas yield in such areas should consider soil salinity and its consequences. Transcription factor (TF) proteins recognize cis-regulatory elements in promoters of genes to be expressed. In the present work, differentially expressed genes (DEGs) encoding putative TFs from physic nut plants responding to NaCl (150 mM), after 3 h of exposition, covered 23 TF families. The expressed profiles of members from AP2/ERF and NAC families basically showed induction after the salt stimulus, while members of bHLH, FHY3-FAR1, and ARF families presented repression. Concerning the induced TF DEGs, the gene ontology (GO) enrichment analysis highlighted terms related to abiotic stress responses, while those terms representing the repressed TF DEGs stood out the basal metabolism. In turn, the TF enrichment analysis predicted those TFs targeting promoters of induced TF DEGs. Some of the enriched TFs may be good candidates as transgenes in transgenic events. Also, RT-qPCR analyses validated the up-regulation of six TF DEGs (RAV1, ERF9, ZAT12, PTI5, MYB340, and BZIP4) of eight candidates selected from the expressed TFome. The generated data could help breeders to better understand the molecular basis of physic nut plants responding to salinity, to select potential candidates for transgenic studies, as well as to develop functional molecular markers to assist selection steps in breeding programs.