title: NAC transcription factors, NST1 and NST3, are key regulators of the formation of secondary walls in woody tissues of Arabidopsis.
abstract: Wood is formed by the successive addition of secondary xylem, which consists of cells with a conspicuously thickened secondary wall composed mainly of lignin and cellulose. Several genes involved in lignin and cellulose biosynthesis have been characterized, but the factors that regulate the formation of secondary walls in woody tissues remain to be identified. In this study, we show that plant-specific transcription factors, designated NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1) and NST3, are key regulators of the formation of secondary walls in woody tissues of Arabidopsis thaliana. In nst1-1 nst3-1 double knockout plants, the secondary wall thickenings in interfascicular fibers and secondary xylem, except for vascular vessels, were completely suppressed without affecting formation of cells destined to be woody tissues. Conversely, as shown previously for NST1, overexpression of NST3 induced ectopic secondary wall thickenings in various aboveground tissues. Furthermore, the expression of chimeric repressors derived from NST1 and NST3 suppressed secondary wall thickenings in the presumptive interfascicular fibers. Because putative orthologs of NST1 and NST3 are present in the genome of poplar, our results suggest that they are also key regulators of the formation of secondary walls in woody plants and could be used as a tool for the genetic engineering of wood and its derivatives.
authors.affiliation: Research Institute of Genome-Based Biofactory, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8562, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Mitsuda
authors.forename: Akira
authors.initials: A
authors.lastname: Iwase
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Masato
authors.initials: M
authors.lastname: Yoshida
authors.forename: Motoaki
authors.initials: M
authors.lastname: Seki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Masaru
authors.initials: M
authors.lastname: Ohme-Takagi
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014934:Wood / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D052584:Xylem / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C510498:NST1 protein, Arabidopsis; C519877:NST3 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors