Genetic Improvement through a Transgenic Approach in Miscanthus Ssp., a New Bioenergy Crop.

Perennial C4 grasses are candidates as energy crops because they have a low demand for nutrient inputs and show higher biomass yields on relatively poor quality land sites and longer persistency and have the merit of increasing the soil carbon sequestration as well as an effect on the stability and cover value for wildlife.  One of the most intensively investigated potential new energy crops is Miscanthus spp. that is native to Asian countries.  Genetic improvement through a transgenic approach has a great impact on the development of novel biofuel crops.  An in vitro culture system in M. sinensis has been established.  Embryogenic callus was induced from mature seeds in MS medium supplemented with 30 g/L sucrose, 5 mg/L 2,4-D and 0.01 mg/L BA. Embryogenic callus was regenerated in MS basal medium supplemented with 30 g/L sucrose, 1 mg/L TDZ and 0.5 mg/L IAA.  Transformation by a particle bombardment technique has been established using embryogenic callus of M. sinensis.  Transgenic plants containing gpf gene and hpt gene were successfully obtained.   We have two strategies for improvement of fermentation efficiency through a transgenic approach.  One of them is obtaining fructan-accumulating transgenic Miscanthus plants by the introduction of fructosyltransferase (FT) genes isolated from C3 grass, perennial ryegrass.  Transgenic calli of M. sinensis containing FT gene from perennial ryegrass were obtained.  Another strategy is transgenic down-regulation of enzymes involved lignin biosynthesis.  Research on RNAi, gene silencing approach is progressing.  We present current statue of molecular breeding of Miscanthus spp..