Objective This study aims to identify the NAC members in waterlily (Nymphaea colorata), and to investigate their evolutionary history and expressions under different tissues and ABA treatment. The current study not only could provide a key theoretical basis on the molecular evolution of the waterlily NAC family, but also could obtain some important candidate genes about regulating floral organ morphogenesis and stress response in waterlily. Method The whole-genome methods were applied to analyze the conserved motifs, gene structures, phylogenetic evolutions, chromosomal locations, gene duplication events, and cis-regulatory elements in the promoter regions of the waterlily NAC family. The expression levels of the waterlily NAC members under different tissues and ABA treatment were performed through the transcriptome and RT-qPCR. Result In this study, 64 NAC members screened from waterlily were divided into 15 subfamilies. The NcNAC members were unevenly distributed on the waterlily's 14 chromosomes, with most members located on chromosomes 1, 2, 9, and 11. Segmental duplication events were prevalent in the expansion of the NcNAC members. Meanwhile, NcNAC11, NcNAC43, NcNAC36 and NcNAC52 were highly expressed in floral organs. Thus, NcNAC11, NcNAC43, NcNAC36 and NcNAC52 may regulate the flower growth and development in waterlily. In addition, numerous stress-responsive regulatory elements were found in the promoter regions of the NcNAC members. NcNAC07, NcNAC08, NcNAC34, and NcNAC43 had the most ABA responsive elements in their promoter regions, and these NcNAC members responded to ABA stress, indicating that NcNAC07, NcNAC08, NcNAC34, and NcNAC43 might be related to stress resistance. Conclusion There are 64 NcNAC members in waterlily, and these NcNACs could be classified into 15 subfamilies. NcNAC11, NcNAC43, NcNAC36 and NcNAC52 have the highest expression in the floral-related tissues, and NcNAC07, NcNAC08, NcNAC34, and NcNAC43 may respond to ABA stress.
