DfCAD16 controls guaiacyl lignin biosynthesis during shoot development in Dendrocalamus farinosus

Although bamboo can be an ideal raw material for pulp and paper industry, the depolymerization of its complex polymers needs to be facilitated. The deposition of lignin is influenced by cinnamyl alcohol dehydrogenase (CAD), an enzyme that catalyzes the formation of monolignol precursors. Here, we identified 18 DfCAD genes in Dendrocalamus farinosus and revealed using bioinformatics methods, DfCAD16 functions as the primary enzyme in the synthesis pathway of guaiacyl (G)-lignin. Phenotypic analysis of plants overexpression DfCAD16 exhibited remarkable increasing in G-lignin. Furthermore, we demonstrated that an R2R3-type MYB transcription factor DfMYB12 could directly bind to the promoter region of DfCAD16 and activate its expression both in vitro and in vivo. Our findings revealed that DfMYB12-DfCAD16 is a key regulatory factor governing G-lignin biosynthesis in D. farinosus. These insights can be used for improving bamboo varieties for pulp production.