Genome-Wide Identification, Expansion, and Evolution Analysis of Homeobox Gene Family Reveals TALE Genes Important for Secondary Cell Wall Biosynthesis in Moso Bamboo ( Phyllostachys edulis ).

The TALE gene family is a subfamily of the homeobox gene family and has been implicated in regulating plant secondary growth. However, reports about the evolutionary history and function of the TALE gene family in bamboo are limited. Here, the homeobox gene families of moso bamboo Olyra latifolia and Bonia amplexicaulis were identified and compared. Many duplication events and obvious expansions were found in the TALE family of woody bamboo. PhTALE s were found to have high syntenies with TALE genes in rice. Through gene co-expression analysis and quantitative real-time PCR analysis, the candidate PhTALE s were thought to be involved in regulating secondary cell wall development of moso bamboo during the fast-growing stage. Among these candidate PhTALE s, orthologs of OsKNAT7 , OSH15 , and SH5 in moso bamboo may regulate xylan synthesis by regulating the expression of IRX-like genes. These results suggested that PhTALE s may participate in the secondary cell wall deposition in internodes during the fast-growing stage of moso bamboo. The expansion of the TALE gene family may be implicated in the increased lignification of woody bamboo when divergent from herbaceous bamboos.