Overexpression of a Domain of Unknown Function 231-containing protein increases O-xylan acetylation and cellulose biosynthesis in .

BACKGROUND

Domain of Unknown Function 231-containing proteins (DUF231) are plant specific and their function is largely unknown. Studies in the model plants Arabidopsis and rice suggested that some DUF231 proteins act in the process of -acetyl substitution of hemicellulose and esterification of pectin. However, little is known about the function of DUF231 proteins in woody plant species.

RESULTS

This study provides evidence supporting that one member of DUF231 family proteins in the woody perennial plant (genotype WV94), PdDUF231A, has a role in the acetylation of xylan and affects cellulose biosynthesis. A total of 52 DUF231-containing proteins were identified in the genome. In transgenic lines overexpressing (), glucose and cellulose contents were increased. Consistent with these results, the transcript levels of cellulose biosynthesis-related genes were increased in the transgenic lines. Furthermore, the relative content of total acetylated xylan was increased in the transgenic lines. Enzymatic saccharification assays revealed that the rate of glucose release increased in transgenic lines. Plant biomass productivity was also increased in transgenic lines.

CONCLUSIONS

These results suggest that PdDUF231A affects cellulose biosynthesis and plays a role in the acetylation of xylan. is a promising target for genetic modification for biofuel production because biomass productivity and compositional quality can be simultaneously improved through overexpression.