title: KORRIGAN1 and its aspen homolog PttCel9A1 decrease cellulose crystallinity in Arabidopsis stems.
abstract: KORRIGAN1 (KOR1) is a membrane-bound cellulase implicated in cellulose biosynthesis. PttCel9A1 from hybrid aspen (Populus tremula L. x tremuloides Michx.) has high sequence similarity to KOR1 and we demonstrate here that it complements kor1-1 mutants, indicating that it is a KOR1 ortholog. We investigated the function of PttCel9A1/KOR1 in Arabidopsis secondary growth using transgenic lines expressing 35S::PttCel9A1 and the KOR1 mutant line irx2-2. The presence of elevated levels of PttCel9A1/KOR1 in secondary walls of 35S::PttCel9A1 lines was confirmed by in muro visualization of cellulase activity. Compared with the wild type, 35S::PttCel9A1 lines had higher trifluoroacetic acid (TFA)-hydrolyzable glucan contents, similar Updegraff cellulose contents and lower cellulose crystallinity indices, as determined by (13)C solid-state nuclear magnetic resonance (NMR) spectroscopy. irx2-2 mutants had wild-type TFA-hydrolyzable glucan contents, but reduced Updegraff cellulose contents and higher than wild-type cellulose crystallinity indices. The data support the hypothesis that PttCel9A1/KOR1 activity is present in cell walls, where it facilitates cellulose biosynthesis in a way that increases the amount of non-crystalline cellulose.
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, SLU, Umeå, Sweden.
authors.forename: Junko
authors.initials: J
authors.lastname: Takahashi
authors.forename: Ulla J
authors.initials: UJ
authors.lastname: Rudsander
authors.forename: Mattias
authors.initials: M
authors.lastname: Hedenström
authors.forename: Alicja
authors.initials: A
authors.lastname: Banasiak
authors.forename: Jesper
authors.initials: J
authors.lastname: Harholt
authors.forename: Nicolas
authors.initials: N
authors.lastname: Amelot
authors.forename: Peter
authors.initials: P
authors.lastname: Immerzeel
authors.forename: Peter
authors.initials: P
authors.lastname: Ryden
authors.forename: Satoshi
authors.initials: S
authors.lastname: Endo
authors.forename: Farid M
authors.initials: FM
authors.lastname: Ibatullin
authors.forename: Harry
authors.initials: H
authors.lastname: Brumer
authors.forename: Elena
authors.initials: E
authors.lastname: del Campillo
authors.forename: Emma R
authors.initials: ER
authors.lastname: Master
authors.forename: Henrik Vibe
authors.initials: HV
authors.lastname: Scheller
authors.forename: Björn
authors.initials: B
authors.lastname: Sundberg
authors.forename: Tuula T
authors.initials: TT
authors.lastname: Teeri
authors.forename: Ewa J
authors.initials: EJ
authors.lastname: Mellerowicz
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005936:Glucans / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D032107:Populus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; D005936:Glucans; C429844:KOR1 protein, Arabidopsis; D008565:Membrane Proteins; D002482:Cellulose; D002480:Cellulase