Identification of the PmNAC Gene Family in Pinus massoniana: PmNAC82 Modulates Wood Biosynthesis by Activating SCW-Related Genes

The NAC transcription factor superfamily is one of the most prominent plant-specific regulatory gene families, extensively participating in multiple metabolic processes that govern plant growth, tissue development and stress adaptation. Masson pine (Pinus massoniana Lamb.) is a native dominant conifer widely cultivated across South China, whose timber resources possess great exploitation potential in pulp manufacturing and the paper industry. In this study, a total of 98 non-redundant NAC family members were mined at the genome-wide level. Functional validation revealed that PmNAC82, a member belonging to the VND evolutionary subgroup, acts as a core regulatory factor controlling wood formation. Subcellular localization tests confirmed PmNAC82 exclusively resides in the cell nucleus. Heterologous genetic transformation in poplar demonstrated that this gene positively regulates the accumulation of lignin and cellulose. Furthermore, through RT-qPCR, yeast one-hybrid assays, and EMSA, we confirmed that PmNAC82 can bind to the promoters of PtrMYB3, PtrMYB21 and PmCesA7. These findings provide a solid foundation for further investigation into the molecular functions of NAC genes in Masson pine as well as their potential application towards molecular breeding strategies aimed at improving wood quality.