Biotech Rice Expressing Exo-glucanase Show Enhanced Production of Reducing Sugars

Tohoku University scientists and partners developed biotech rice with improved production of reducing sugars by expression of EXG exo-glucanase under the control of senescence-inducible promoter. When a GUS coding sequence was connected to a promoter region of STAY GREEN (SGR) gene of rice and introduced into rice, GUS activity was specifically observed along with senescence. When an EXG1 cDNA was connected to the SGR promoter and introduced into rice, higher cellulase activities were detected after senescence.

The biotech rice plants exhibited enhanced saccharification efficiencies after senescence or biological aging. However, there was no significant difference of saccharification efficiencies observed before senescence. The saccharification efficiencies were found to be linked with cellulase activities in the biotech rice plants. Furthermore, the biotech rice plants did not exhibit physical deformity as well as reproductive glitch after EXG1 was overexpressed. Based on the findings, the expression of cellulase and other cell wall degrading enzymes can improve the saccharification ability of cellulosic biomass without hampering growth for efficient production of biofuels.

Read the abstract at http://link.springer.com/article/10.1007/s11248-014-9786-z.