Fig. 1

Integrated model of monolignol biosynthesis pathway and the underlying regulatory mechanism in Miscanthus × giganteus. a The proposed monolignol biosynthesis pathway in M. × giganteus. The enzymes beside the arrows are the major monolignol biosynthetic enzymes identified in this study. The gray arrows indicate the enzymatic reactions are not supported (CSE) or not the main route (from phenylalanine to p-coumaric acid). The dashed arrow means the reaction is not yet clear in M. × giganteus (C3H). b The transcription factors (TFs) that are predicted to participate in the monolignol biosynthesis in M. × giganteus. The lines with arrows and bars at the ends represent promoting and suppressing the expression of monolignol biosynthetic genes, respectively. The MYBs, WRKYs, and ERFs are likely to directly regulate the expression of monolignol biosynthetic genes, while the secondary wall NACs (SWNs) are supposed to function indirectly. For each family, the top three TFs are shown in the figure, and the rest are listed in Additional file 2: Table S9