In collaboration with the University of Melbourne, the University of British Columbia, and other parties, the researchers discovered genes that regulate formation of the plant primary cell walls, produced lignin-free cell walls by introduction of the discovered genes, and demonstrated that the resulting glucose yield is approximately twice the wild-type level.

Wild-type Arabidopsis thaliana (left), nst1 nst3 double mutant lacking secondary cell walls (center), and newly developed transgenic plant (right)

Woody biomass resources can help reduce CO₂ emissions as they can be a source of next-generation biofuels and biomaterials. However, lignin contained in plant secondary cell walls (wood) inhibits biomass decomposition, which has been an obstacle to fuel and material production. Therefore, development of low-lignin woody biomass resources has been demanded.

Arabidopsis thaliana was used as a model plant, and around 300 out of approximately 1800 transcription factors were selected and introduced to a mutant that does not form secondary cell walls. All of the plants to which the transcription factors were introduced were analyzed, and approximately 10 transcription factors were found to induce thickened primary cell wall-like cell wall formation in the mutant. Fiber cells in these transgenic plants contain almost no lignin despite the thickened cell walls, and therefore biomass decomposition was performed more efficiently.

The researchers will develop technology that can produce wood suitable for industrial use while maintaining properties close to those of natural wood, by additionally accumulating the cell wall components usually contained in wood on the thickened primary cell wall-like cell walls.