p?\Coumaroyl ester 3?\hydroxylase (C3¨@H) is a key enzyme involved in the
synthesis of lignin, a major component in vascular plants' secondary cell
walls. Although the crucial role of C3¨@H in have been investigated, there
is limited information available for its role in monocotyledonous grass
species. The team of Yuri Takeda from Kyoto University in Japan studied the
effect of C3¨@H?\deficiency on the structure and properties of grass cell
C3¨@H?\knockdown lines generated via RNAi gene silencing, with approximately
0.5% of the normal expression level, reached maturity and set seeds.
Meanwhile, C3¨@H?\knockout rice mutants generated via CRISPR-Cas9
mutagenesis were severely dwarfed and sterile.
Analysis of the mature C3¨@H?\knockdown RNAi lines revealed that their
lignin were enriched in p?\hydroxyphenyl (H) units and had reduced levels of
the normally dominant guaiacyl (G) and syringyl (S) units. Suppression of C3
¨@H also resulted in substantial reduction in cell wall cross?\linking. The
C3¨@H?\suppressed rice exhibited enhanced biomass saccharification.
These data demonstrate that C3¨@H expression is an important determinant of
lignin content and composition as well as the degree of cell wall cross?\