title: Functional Characterization of Populus PsnSHN2 in Coordinated Regulation of Secondary Wall Components in Tobacco.
abstract: Wood formation is a biological process during which the most abundant lignocellulosic biomass on earth is produced. Although a number of transcription factors have been linked to the regulation of wood formation process, none of them has been demonstrated to be a higher hierarchical regulator that coordinately regulates secondary wall biosynthesis genes. Here, we identified a Populus gene, PsnSHN2, a counterpart of the Arabidopsis AP2/ERF type transcription factor, SHINE2. PsnSHN2 is predominantly expressed in xylem tissues and acted evidently as a high hierarchical transcriptional activator. Overexpression of PsnSHN2 in tobacco significantly altered the expression of both transcription factors and biosynthesis genes involved in secondary wall formation, leading to the thickened secondary walls and the changed cell wall composition. The most significant changes occurred in the contents of cellulose and hemicellulose that increased 37% and 28%, respectively, whereas the content of lignin that decreased 34%. Furthermore, PsnSHN2 activated or repressed the promoter activities of transcription factors involved in secondary wall biosynthesis and bound to five cis-acting elements enriched in the promoter regions of these transcription factors. Taken together, our results suggest PsnSHN2 coordinately regulate secondary wall formation through selective up/down-regulation of its downstream transcription factors that control secondary wall formation.
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Heilongjiang Harbin, 150040, P.R. China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Heilongjiang Harbin, 150040, P.R. China.
authors.forename: Minjing
authors.initials: M
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Heilongjiang Harbin, 150040, P.R. China.
authors.forename: Cong
authors.initials: C
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Heilongjiang Harbin, 150040, P.R. China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Lu
authors.forename: Lulu
authors.initials: L
authors.lastname: Liu
authors.affiliation: School of Forest Resource and Environmental Science, Michigan Technological University, Houghton, MI, 49931, USA.
authors.forename: Hairong
authors.initials: H
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Heilongjiang Harbin, 150040, P.R. China. chengyuxiang@nefu.edu.cn.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Heilongjiang Harbin, 150040, P.R. China. zhigangwei1973@163.com.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wei
mesh_terms: D002473:Cell Wall; D002482:Cellulose / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008031:Lignin / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D032107:Populus / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D014026:Nicotiana / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D014934:Wood / Q000235:genetics / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D011134:Polysaccharides; D014157:Transcription Factors; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin