Comprehensive analysis of NAC transcription factors and their expressions during taproot coloration in radish (Raphanus sativus L.).

• A total 183 RsNACs were identified in radish using the long-read genome 'QZ-16' • The gene location, collinearity, phylogeny, and gene structure were performed. • Ten RsNACs were found to be related to taproot coloration in radish. Taproot color is a key trait for assessing their commercial value of radish cultivars. Although the plant-specific NAC (NAM, ATAF, and CUC) transcription factors (TFs) have demonstrated roles in several plant development processes, their functions in radish taproot coloration remain largely unknown. In this study, 183 NAC members were identified from the long-read genome 'QZ-16' of radish. Phylogenetic analysis indicated that the NAC members in radish, rice and Arabidopsis were clustered into 18 groups. Synteny analysis revealed that a total of 30 segmental duplication and 5 tandem duplication events occurred in RsNAC genes. Transmission electron microscopy observation showed that the lack of chloroplast led to taproot color change from green to totally white in radish. Furthermore, when comparing green radish 'QZ-16' and white radish '55', ten RsNAC differentially expressed genes (DEGs) were identified by RNA-seq, which were found to be related to taproot coloration in radish. These findings would lay a solid foundation for the investigation of the relationship between taproot coloration and RsNAC gene functions in radish. [ABSTRACT FROM AUTHOR]