title: ANAC012, a member of the plant-specific NAC transcription factor family, negatively regulates xylary fiber development in Arabidopsis thaliana.
abstract: Vascular plants evolved to have xylem that provides physical support for their growing body and serves as a conduit for water and nutrient transport. In a previous study, we used comparative-transcriptome analyses to select a group of genes that were upregulated in xylem of Arabidopsis plants undergoing secondary growth. Subsequent analyses identified a plant-specific NAC-domain transcription factor gene (ANAC012) as a candidate for genetic regulation of xylem formation. Promoter-GUS analyses showed that ANAC012 expression was preferentially localized in the (pro)cambium region of inflorescence stem and root. Using yeast transactivation analyses, we confirmed the function of ANAC012 as a transcriptional activator, and identified an activation domain in the C terminus. Ectopic overexpression of ANAC012 in Arabidopsis (35S::ANAC012 plants) dramatically suppressed secondary wall deposition in the xylary fiber and slightly increased cell-wall thickness in the xylem vessels. Cellulose compositions of the cell wall were decreased in the inflorescent stems and roots of 35S::ANAC012 plants, probably resulting from defects in xylary fiber formation. Our data suggest that ANAC012 may act as a negative regulator of secondary wall thickening in xylary fibers.
authors.affiliation: Department of Forestry, 126 Natural Resources, Michigan State University, East Lansing, MI 48824-1222, USA.
authors.forename: Jae-Heung
authors.initials: JH
authors.lastname: Ko
authors.forename: Seung Hwan
authors.initials: SH
authors.lastname: Yang
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Park
authors.forename: Olivier
authors.initials: O
authors.lastname: Lerouxel
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Han
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D015870:Gene Expression; D020869:Gene Expression Profiling; D017343:Genes, Plant; D008969:Molecular Sequence Data; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D052584:Xylem / Q000254:growth & development*
chemical_list: C522475:ANAC012 protein, Arabidopsis; D029681:Arabidopsis Proteins; D014157:Transcription Factors