Enhancement of growth by expression of poplar cellulase in Arabidopsis thaliana.

To study the role of cellulose and cellulase in plant growth, we expressed poplar cellulase (PaPopCel1) constitutively in Arabidopsis thaliana. Expression increased the size of the rosettes due to increased cell size. The change in growth was accompanied by changes in biomechanical properties due to cell wall structure indicative of decrease in xyloglucan cross-linked with cellulose microfibrils by chemical analysis and nuclear magnetic resonance (NMR) spectra. The result supports the concept that the paracrystalline sites of cellulose microfibrils are attacked by poplar cellulase to loosen xyloglucan intercalation and this irreversible wall modification promotes the enlargement of plant cells.