Genome-wide identification and characterization of genes in var. .

Background: NAC (NAM, ATAF1/2, and CUC2) transcription factors play an important role in plant growth and development. However, in tumorous stem mustard ( var. ), one of the economically important crops cultivated in southwest China and some southeast Asian countries, reports on the identification of family genes are lacking. In this study, we conducted a genome-wide investigation of the family genes in . var. , based on its recently published genome sequence data.

Methods: The genes were identified in . var. using the bioinformatics approach on the whole genome level. Additionally, the expression of genes was analyzed under high- and low-temperature stresses by quantitative real-time PCR (qRT-PCR).

Results: A total of 300 genes were identified, of which 278 were mapped to specific chromosomes. Phylogenetic analysis of . var. , , , rice and NAC proteins revealed that all genes were divided into 18 subgroups. Furthermore, gene structure analysis showed that most of the genes contained two or three exons. Conserved motif analysis revealed that genes contain a conserved NAM domain. Additionally, qRT-PCR data indicated that thirteen genes with a varying degree of up-regulation during high-temperature stress. Conversely, four genes (, , and ) were up-regulated and two genes ( and ) down-regulated under low temperature, respectively. Together, the results of this study provide a strong foundation for future investigation of the biological function of genes in . var. .