Genome-wide characterization and expression profiling of<i>NAC</i>transcription factor genes under abiotic stresses in radish (<i>Raphanus sativus</i>L.)

Abstract

NAC (NAM, no apical meristem; ATAF, <i>Arabidopsis</i> transcription activation factor and CUC, cup-shaped cotyledon) proteins are among the largest transcription factor (TF) families playing fundamental biological processes, including cell expansion and differentiation, and hormone signaling in response to biotic and abiotic stresses. In this study, 172 RsNACs comprising 17 membrane-bound members were identified from the whole radish genome. In total, 98 <i>RsNAC</i> genes were non-uniformly distributed across the nine radish chromosomes. <i>In silico</i> analysis revealed that expression patterns of several <i>NAC</i> genes were tissue-specific such as a preferential expression in roots and leaves. In addition, 21 representative <i>NAC</i> genes were selected to investigate their responses to heavy metals (HMs), salt, heat, drought and abscisic acid (ABA) stresses using real-time polymerase chain reaction (RT-qPCR). As a result, differential expressions among these genes were identified where <i>RsNAC023</i> and <i>RsNAC080</i> genes responded positively to all stresses except ABA, while <i>RsNAC145</i> responded more actively to salt, heat and drought stresses compared with other genes. The results provides more valuable information and robust candidate genes for future functional analysis for improving abiotic stress tolerances in radish.