Coexpression network of MaNAC, MaMYB and lignin biosynthesis-related genes and their regulatory network. (a) Coexpression network of MaNAC, MaMYB and lignin biosynthesis-related genes. The green circle represents lignin biosynthesis-related genes that are expressed downstream of NACs and MYBs, the blue circle represents MYB TFs, the pink circle represents NAC TFs, the pink triangle represents lignin biosynthesis-related NAC genes, and the blue rhombus represents lignin biosynthesis-related MYB genes. 4CL: 4-coumarate CoA Ligase, BGL: β-glucosidase, CAD: cinnamyl alcohol dehydrogenase, CCoAOMT: caffeoyl CoA O-methyltransferase, COMT: caffeic acid O-methyltransferase, HCT: hydroxycinnamoyl transferase, PAL: phenylalanine ammonia-lyase. The color of the line represents the weight value between two nodes. (b) Regulatory network of MaNAC, MaMYB and lignin biosynthesis-related genes. The heatmap below the gene name shows the gene expression pattern of five leaf samples. The heatmap represents the gene number in the horizontal direction and the expression level in the vertical direction for five leaf samples.