文献类型：期刊文献

英文题名：Growth-regulating factor 15-mediated vascular cambium differentiation positively regulates wood formation in hybrid poplar (Populus alba x P. glandulosa)

作者：Zhou, Houjun[1] Song, Xueqin[2] Lu, Meng-Zhu[3]

第一作者：Zhou, Houjun

通信作者：Zhou, HJ[1];Song, XQ[2]

机构：[1]Ludong Univ, Engn Res Inst Agr & Forestry, Yantai, Peoples R China;[2]Chinese Acad Forestry, Res Inst Forestry, State Key Lab Tree Genet & Breeding, Beijing, Peoples R China;[3]Zhejiang A&F Univ, Coll Forestry & Biotechnol, State Key Lab Subtrop Silviculture, Hangzhou, Peoples R China

年份：2024

卷号：15

外文期刊名：FRONTIERS IN PLANT SCIENCE

收录：;WOS:【SCI-EXPANDED(收录号:WOS:001174590200001)】；

基金：The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the National Natural Science Foundation of China (Grant no. 32001330, 31570676).

语种：英文

外文关键词：hybrid poplar; PagGRF15; vascular cambium; division; xylem differentiation

摘要：Introduction: Hybrid poplars are industrial trees in China. An understanding of the molecular mechanism underlying wood formation in hybrid poplars is necessary for molecular breeding. Although the division and differentiation of vascular cambial cells is important for secondary growth and wood formation, the regulation of this process is largely unclear. Methods: In this study, mPagGRF15 OE and PagGRF15-SRDX transgenic poplars were generated to investigate the function of PagGRF15. RNA-seq and qRT-PCR were conducted to analyze genome-wide gene expression, while ChIP-seq and ChIP-PCR were used to identified the downstream genes regulated by PagGRF15. Results and discussion: We report that PagGRF15 from hybrid poplar (Populus alba x P. glandulosa), a growth-regulating factor, plays a critical role in the regulation of vascular cambium activity. PagGRF15 was expressed predominantly in the cambial zone of vascular tissue. Overexpression of mPagGRF15 (the mutated version of GRF15 in the miR396 target sequence) in Populus led to decreased plant height and internode number. Further stem cross sections showed that the mPagGRF15 OE plants exhibited significant changes in vascular pattern with an increase in xylem and a reduction in phloem. In addition, cambium cell files were decreased in the mPagGRF15 OE plants. However, dominant suppression of the downstream genes of PagGRF15 using PagGRF15-SRDX showed an opposite phenotype. Based on the RNA-seq and ChIP-seq results, combining qRT-PCR and ChIP-PCR analysis, candidate genes, such as WOX4b, PXY and GID1.3, were obtained and found to be mainly involved in cambial activity and xylem differentiation. Accordingly, we speculated that PagGRF15 functions as a positive regulator mediating xylem differentiation by repressing the expression of the WOX4a and PXY genes to set the pace of cambial activity. In contrast, PagGRF15 mediated the GA signaling pathway by upregulating GID1.3 expression to stimulate xylem differentiation. This study provides valuable information for further studies on vascular cambium differentiation mechanisms and genetic improvement of the specific gravity of wood in hybrid poplars.