抄録
Recent environmental issues have prompted an increase in the demand for wood, so it is important to understand the process of wood formation. We focused on 16 poplar (Populus trichocarpa) NAC domain protein genes, PtVNS (VND, NST/SND and SMB related proteins) genes, which are homologous to Arabidopsis transcription factors regulating the differentiation of xylem vessels and fiber cells. 12 PtVNS genes including both VND and NST groups were expressed in developing xylem tissue and phloem fiber, whereas in primary xylem vessels, only the VND group genes were expressed. By using the post-translational induction system of AtVND7, a master regulator of xylem vessel differentiation, many poplar genes functioning in xylem vessel differentiation were identified. Transient expression assays showed the variation in PtVNS transactivation activity toward downstream genes. Moreover, overexpression of PtVNS genes induced ectopic secondary wall thickening in poplar leaves as well as in Arabidopsis seedlings with different levels of induction efficiency according to the gene. These results suggest that wood formation in poplar is regulated by cooperative functions of the NAC domain proteins.
