PagDAG基因过表达对84K杨生长及维管组织发育的影响OA

To dissect the functions of Dof transcription factor PagDAG in poplar growth and vascular tissue development,Populus alba×P.glandulosa clone 84K was used as experimental material in this study.The PagDAG overexpression vector driven by the CaMV 35S promoter was constructed,and overexpression lines(OE-PagDAG)were generated via the Agrobacteri-um tumefaciens(strain GV3101)-mediated leaf disc transformation method.Growth indicators of wild-type and overex-pression plants were measured.Combined with cross-section observation of stem internodes stained by phloroglucinol and toluidine blue as well as cell wall component quantification,the effects of PagDAG overexpression on plant growth and vas-cular tissue development were systematically analyzed.The results showed that compared with wild-type plants,PagDAG overexpression significantly retarded plant growth:plant height decreased by 9.94%and 11.79%,while ground diameter was reduced by 8.39%and 8.00%,respectively.Vascular tissue development was markedly suppressed,with the relative xylem area declining by 20.6%and 16.3%.Meanwhile,the cell wall thickness of phloem fibers decreased by 17.6%and 24.1%,and the lignin content in plant stems was lowered by 25.9%and 29.9%.Collectively,these results indicate that PagDAG may negatively regulate vascular tissue development and cell wall component deposition,participate in the growth regulation of 84K poplar,and play a vital role in wood formation.