Genome-Wide Analysis of the <i>NAC</i> Gene Family in Physic Nut (<i>Jatropha curcas</i> L.)

<div><p>The NAC proteins (NAM, ATAF1/2 and CUC2) are plant-specific transcriptional regulators that have a conserved NAM domain in the N-terminus. They are involved in various biological processes, including both biotic and abiotic stress responses. In the present study, a total of 100 <i>NAC</i> genes (<i>JcNAC</i>) were identified in physic nut (<i>Jatropha curcas</i> L.). Based on phylogenetic analysis and gene structures, 83 <i>JcNAC</i> genes were classified as members of, or proposed to be diverged from, 39 previously predicted orthologous groups (OGs) of NAC sequences. Physic nut has a single intron-containing <i>NAC</i> gene subfamily that has been lost in many plants. The <i>JcNAC</i> genes are non-randomly distributed across the 11 linkage groups of the physic nut genome, and appear to be preferentially retained duplicates that arose from both ancient and recent duplication events. Digital gene expression analysis indicates that some of the <i>JcNAC</i> genes have tissue-specific expression profiles (e.g. in leaves, roots, stem cortex or seeds), and 29 genes differentially respond to abiotic stresses (drought, salinity, phosphorus deficiency and nitrogen deficiency). Our results will be helpful for further functional analysis of the <i>NAC</i> genes in physic nut.</p>