A genomics approach to deciphering lignin biosynthesis in switchgrass.

Abstract

It is necessary to overcome recalcitrance of the biomass to saccharification (sugar release) to make switchgrass (Panicum virgatum) economically viable as a feedstock for liquid biofuels. Lignin content correlates negatively with sugar release efficiency in switchgrass, but selecting the right gene candidates for engineering lignin biosynthesis in this tetraploid outcrossing species is not straightforward. To assist this endeavor, we have used an inducible switchgrass cell suspension system for studying lignin biosynthesis in response to exogenous brassinolide. By applying a combination of protein sequence phylogeny with whole-genome microarray analyses of induced cell cultures and developing stem internode sections, we have generated a list of candidate monolignol biosynthetic genes for switchgrass. Several genes that were strongly supported through our bioinformatics analysis as involved in lignin biosynthesis were confirmed by gene silencing studies, in which lignin levels were reduced as a result of targeting a single gene. However, candidate genes encoding enzymes involved in the early steps of the currently accepted monolignol biosynthesis pathway in dicots may have functionally redundant paralogues in switchgrass and therefore require further evaluation. This work provides a blueprint and resources for the systematic genome-wide study of the monolignol pathway in switchgrass, as well as other C4 monocot species.

• Authors: Hui Shen, Mitra Mazarei, Hiroshi Hisano, Luis Escamilla-Trevino, Chunxiang Fu, Yunqiao Pu, Mary R Rudis, Yuhong Tang, Xirong Xiao, Lisa Jackson, Guifen Li, Tim Hernandez, Fang Chen, Arthur J Ragauskas, C Neal Stewart Jr, Zeng-Yu Wang, Richard A Dixon
• Journal: The Plant cell (Plant Cell) Vol. 25 Issue 11 Pg. 4342-61 (Nov 2013) ISSN: 1532-298X [Electronic] England
• PMID: 24285795 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Enzymes
• Lignin

Topics

• Biosynthetic Pathways (genetics)
• Cell Culture Techniques
• Cloning, Molecular
• Cluster Analysis
• Enzymes (genetics, metabolism)
• Gene Expression Regulation, Plant
• Gene Silencing
• Genomics (methods)
• Lignin (biosynthesis, genetics)
• Molecular Sequence Annotation
• Molecular Sequence Data
• Panicum (cytology, genetics, metabolism)
• Phylogeny
• Plants, Genetically Modified