Vessel-specific reintroduction of CINNAMOYL COA REDUCTASE 1 (CCR1) in dwarfed ccr1 mutants restores vessel and xylary fiber integrity and increases biomass.

5 years ago

Vessel-specific reintroduction of CINNAMOYL COA REDUCTASE 1 (CCR1) in dwarfed ccr1 mutants restores vessel and xylary fiber integrity and increases biomass.

Merve Özparpucu, Notburga Gierlinger, Ruben Vanholme, Geert Goeminne, Kris Morreel, Lisanne de Vries, Barbara De Meester, Michiel De Bruyne, Riet Maria De Rycke, Sander Corneillie, Andreas Pallidis, Wout A Boerjan

Lignocellulosic biomass is recalcitrant towards deconstruction into simple sugars due to the presence of lignin. To render lignocellulosic biomass a suitable feedstock for the bio-based economy, plants can be engineered to have decreased amounts of lignin. However, engineered plants with the lowest amounts of lignin exhibit collapsed vessels and yield penalties. Previous efforts were not able to fully overcome this phenotype, without settling in sugar yield upon saccharification. Here, we reintroduced CINNAMOYL-CoA REDUCTASE 1 (CCR1) expression specifically in the proto- and metaxylem vessel cells of Arabidopsis ccr1 mutants. The resulting ccr1 ProSNBE:CCR1 lines had overcome the vascular collapse and had a total stem biomass yield that was increased up to 59% as compared to wild type. Raman analysis showed that monolignols synthesized in the vessels also contribute to lignification of neighboring xylary fibers. The cell wall composition and metabolome of ccr1 ProSNBE:CCR1 still exhibited many similarities to those of ccr1 mutants, regardless of their yield increase. In contrast to a recent report, the yield penalty of ccr1 mutants was not caused by ferulic acid accumulation, but was (largely) the consequence of collapsed vessels. Finally, ccr1 ProSNBE:CCR1 plants had a fourfold increase in total sugar yield when compared to wild-type plants.

Publisher URL: http://doi.org/10.1104/pp.17.01462

DOI: 10.1104/pp.17.01462