|Title||KORRIGAN1 and its Aspen Homolog PttCel9A1 Decrease Cellulose Crystallinity in Arabidopsis Stems|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Takahashi, J, Rudsander, UJ, Hedenstrom, M, Banasiak, A, Harholt, J, Amelot, N, Immerzeel, P, Ryden, P, Endo, S, Ibatullin, FM, Brumer, H, del Campillo, E, Master, ER, Scheller, HVibe, Sundberg, B, Teeri, TT, Mellerowicz, EJ|
|Journal||PLANT AND CELL PHYSIOLOGY|
|Type of Article||Article|
KORRIGAN1 (KOR1) is a membrane-bound cellulase implicated in cellulose biosynthesis. PttCel9A1 from hybrid aspen (Populus tremula L. 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.