GAUT12 Gene Causes Increased Recalcitrance and Decreased Growth in Populus

The development of fast-growing hardwood trees as a source of biomass for biofuel production requires a good understanding of the plant cell wall structure and mechanisms that underlie the recalcitrance of woody biomass. Downregulation of the GAUT12.1 gene in poplar (Populus deltoids) was reported to result in improved biomass saccharification, plant growth, and biomass yield.

To further understand GAUT12.1 function, the team of Ajaya K. Biswal from the University of Georgia overexpressed the black cottonwood (Populus trichocarpa) PtGAUT12.1 gene in poplar. Overexpressing PtGAUT12.1 in poplar resulted in a nearly complete opposite biomass saccharification and plant growth phenotype to that of PdGAUT12.1-knockdown (KD) lines. This included significantly reduced glucose, xylose, and total sugar release, plant height, stem diameter, and overall total aerial biomass yield compared to controls. Total lignin content was unaffected by the gene overexpression.

The combined data from P. deltoids, PtGAUT12.1-overexpressing lines and PdGAUT12.1-knockdown lines establish GAUT12.1 as a recalcitrance- and growth-associated gene in poplar.