NAC and MYB Families and Lignin Biosynthesis-Related Members Identification and Expression Analysis in .

is an annual or biennial legume species that adapts to extreme environments via its high stress tolerance. NAC and MYB transcription factors (TFs) are involved in the regulation of lignin biosynthesis, which has not been studied in . A total of 101 and 299 members were identified based on genome. Chromosome distribution and synteny analysis indicated that some genes underwent tandem duplication. Ka/Ks analysis suggested that s and s underwent strong purifying selection. Stress-, hormone- and development-related cis-elements and MYB-binding sites were identified in the promoter regions of and . Five s, two s and ten lignin biosynthesis genes were identified as presenting coexpression relationships according to weighted gene coexpression network analysis (WGCNA). Eleven and thirteen candidate and genes related to lignin biosynthesis were identified, respectively, and a network comprising these genes was constructed which further confirmed the and relationship. These candidate genes had conserved gene structures and motifs and were highly expressed in the stems and roots, and qRT-PCR further verified the expression patterns. Overall, our results provide a reference for determining the precise role of and genes in and may facilitate efforts to breed low-lignin-content forage cultivars in the future.