Genome-Wide Investigation of the NAC Gene Family and Its Potential Association with the Secondary Cell Wall in Moso Bamboo.

NAC (NAM, ATAF, and CUC) transcription factors (TFs) are implicated in the transcriptional regulation of diverse processes and have been characterized in a number of plant species. However, NAC TFs are still not well understood in bamboo, especially their potential association with the secondary cell wall (SCW). Here, 94 s were identified and characterized in moso bamboo (). Based on their gene structures and conserved motifs, the PeNACs were divided into 11 groups according to their homologs in . s were expressed variously in different tissues of moso bamboo, suggesting their functional diversity. Fifteen s associated with the SCW were selected for co-expression analysis and validation. It was predicted that 396 genes were co-expressed with the 15 s, in which 16 and 55 genes were involved in the lignin catabolic process and cellulose biosynthetic process respectively. As the degree of lignification in the growing bamboo shoots increased, all 15 s were upregulated with a trend of rising first and then decreasing except , which increased continuously. These results indicated that these s might play important roles in SCW biosynthesis and lignification in bamboo shoots. Seven of 15 s had been found positively co-expressed with seven s, and they had similar expression patterns with those of the s in bamboo shoots. The targeted sites of miR164 were found in 16 s, of which three s associated with SCW were validated to have an opposite expression trend to that of miR164 in growing bamboo shoots. In addition, three s were selected and verified to have self-activation activities. These results provide comprehensive information of the gene family in moso bamboo, which will be helpful for further functional studies of s to reveal the molecular regulatory mechanisms of bamboo wood property.