It is necessary to alleviate environmental and economic disadvantages of fossil fuels for global warming. Among the conceivable options, the use of plant biomass for the production of bioethanol is considered as a potential alternative for fossil fuels. Plant biomass that contains lignocellulose for bioethanol production has recently emerged as biofuel feedstock because of its sustainable and environment-friendly properties. However, lignin inhibits the hydrolysis process and the lignin recalcitrance in ethanol conversion remains in a problem. The attempt for down-regulating enzymes involved in lignin biosynthesis is one of attractive strategy to reduce the lignin contents. Recently, Brachypodium distachyon has been proposed as an alternative monocotyledon model species. The close phylogenetic relationship of Brachypodium with other grasses suggests that the Brachypodium may be useful for structural and functional genomic studies in these species. Brachypodium, standard line Bd21, was subjected to irradiation at doses of 50, 100, 150, 200, and 250 Gy. Phenotypes were investigated using M0:2 population. Through histochemical analysis using phloroglucinol, 25 M2 putative lignin deficient mutants were selected. Depend on the phenotypic and histochemical data, mutants were selected and used for measuring lignin content. Total lignin content was measured using the acetyl bromide (AcBr). Mutant #142-3-1 contains 16.9 (mg/g dry cell wall) of total lignin and the lignin level was significantly reduced (87.9%) compared to wild-type (19.23 mg/g dry cell wall). Additionally, Mutant line #2259-1-2 reduced lignin level at 94.4% (18.15 mg/g dry cell wall) in comparison to wild-type. The enzymatic hydrolyses in lignin deficient lines have been performing with the time courses. Lignin composition, cell wall carbohydrates, and genetic analysis in mutant lines will be discussed.

• Man Bo Lee(Dept. of Biotechnology, Korea University)
• Yong Weon Seo(Dept. of Biotechnology, Korea University) Corresponding Author