TALEN-Mediated Editing of the Caffeic Acid 3-O-Methyltransferase for Genetic Improvement of the Biofuel Feedstock Sugarcane

Transcription activator-like effector nuclease (TALEN) is a recently developed tool enabling precise genome modifications, such as targeted mutagenesis, gene replacement, or insertion. Sugarcane is a prime feedstock for bioethanol production, and utilizing both sucrose and cell wall bound sugars for fermentation will enhance the biofuel yield. We recently demonstrated that RNAi mediated downregulation of lignin biosynthetic genes is a successful strategy to improve bioethanol production from lignocellulosic sugarcane biomass. In this study, one of the lignin biosynthetic genes, Caffeic acid O-methyltransferase (COMT) was targeted for the TALEN induced mutagenesis to modify lignin biosynthesis in sugarcane. Targeted mutations following TALEN delivery were identified by capillary electrophoresis of the COMT amplicon. Events were confirmed by sequencing of the COMT amplicon which revealed the presence of insertions and deletions at the target site. Data describing the total lignin content in the stem biomass of COMT mutants will be presented.