title: Antisense expression of the fasciclin-like arabinogalactan protein FLA6 gene in Populus inhibits expression of its homologous genes and alters stem biomechanics and cell wall composition in transgenic trees.
abstract: Fasciclin-like arabinogalactan proteins (FLAs) play important roles in the growth and development of roots, stems, and seeds in Arabidopsis. However, their biological functions in woody plants are largely unknown. In this work, we investigated the possible function of PtFLA6 in poplar. Quantitative real-time PCR, PtFLA6-yellow fluorescent protein (YFP) fusion protein subcellular localization, Western blotting, and immunohistochemical analyses demonstrated that the PtFLA6 gene was expressed specifically in the xylem of mature stem, and PtFLA6 protein was distributed ubiquitous in plant cells and accumulated predominantly in stem xylem fibres. Antisense expression of PtFLA6 in the aspen hybrid clone Poplar davidiana×Poplar bolleana reduced the transcripts of PtFLA6 and its homologous genes. Transgenic plants that showed a significant reduction in the transcripts of PtFLAs accumulated fewer PtFLA6 and arabinogalactan proteins than did the non-transgenic plants, leading to reduced stem flexural strength and stiffness. Further studies revealed that the altered stem biomechanics of transgenic plants could be attributed to the decreased cellulose and lignin composition in the xylem. In addition expression of some xylem-specific genes involved in cell wall biosynthesis was downregulated in these transgenic plants. All these results suggest that engineering the expression of PtFLA6 and its homologues could modulate stem mechanical properties by affecting cell wall composition in trees.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, PR China.
authors.forename: Haihai
authors.initials: H
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, PR China.
authors.forename: Chunmei
authors.initials: C
authors.lastname: Jiang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, PR China.
authors.forename: Cuiting
authors.initials: C
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, PR China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Gao
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, PR China hxzhang@sippe.ac.cn.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Zhang
mesh_terms: D001696:Biomechanical Phenomena; D002473:Cell Wall / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016373:DNA, Antisense / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D009088:Mucoproteins / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018547:Plant Stems / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D032107:Populus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D052584:Xylem / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D016373:DNA, Antisense; D009088:Mucoproteins; D010940:Plant Proteins; C006619:arabinogalactan proteins
keywords: Biomechanics; Populus; cell wall; fasciclin-like arabinogalactan protein; transgenic plant; xylem.