Abstract
To elucidate the cellulose synthesis mechanism, we isolated a mutant of Arabidopsis (css1) that showed changed sensitivity to cellulose biosynthesis inhibitor. The analysis of phenotypes indicated that the css1 mutation influenced various fundamental metabolisms including amino acid metabolism, triacylglycerol degradation and polysaccharide synthesis (cellulose and starch). Unexpectedly the map-based cloning of responsible gene for the mutation identified a protein that was assumed a splicing factor of mitochondrial group II intron. In accordance with this result, this mutant exhibited improper splicing of NAD4 transcript. We seem that defect in the function of mitochondria influences various aspects of basic metabolism including cellulose synthesis. It is also possible that At-nMat1 gene product influences nuclear gene expression utilizing its RNA-related activity. Our results suggested that sucrose synthase (SuSy), an enzyme involved in the biosynthesis of cellulose, plays key roles in the connection between mitochondria and cellulose synthesis.
