Cell Wall Traits And Enzymatic Digestibility Relevant Gene And QTL In Rice Culm

It is meaningful if China's rich rice straw resource can be used as biomass residues for biofuels. Genetic modification of plant cell wall relative genes has been proposed as a promising solution to reach the goal. In this research, we explored the possibility whether the rice brittle culm mutant c17 could be used as an energy variety, and analyzed the structure factors as well as quantitative trait locus affecting cell wall enzymatic digistibility using a rice recombinant inbred line population.Through map-based cloning, we found the formation of the brittle culm mutant c17 was caused by a mutation in the OsDRP2B, which belongs to the dynamin gene family. The 1000-grain weight, panicle length, biomass yield and lodging resistance in cl7 had no significant difference compared with the wild type. The number of effective panicle and the ability of resistancing bacterial blight in the mutant were remarkably improved. Meanwhile, c17 exhibited a much higher biomass enzymatic digestibility upon various acid and alkali pretreatments. The data indicated that the mutant c17 could be applied for energy crop breeding.Correlation analysis and QTL mapping had been made toward 32 cell wall relative traits in F12 recombinant inbred line population from the cross between Huahui3/Zhongguoxiangdao. We found there were significantly positive correlations between C5 production and mannose molar percent, the ratio of mannose molar and dry weight, the molar percent of xylose, S and H, H/G?H/S and S/G; The ratio of molar and dry weight and molar percent of arabinose, fucose, galactose, rhamnose, the molar percent of G and the ratio of molar and dry weight of S, H, G, S+H+G had significant negative correlations with C5 production. The ratio of molar and dry weight and molar percent of glucose, mannose and the ratio of molar and dry weight of H were positive factors for C6 production; The ratio of molar and dry weight and molar percent of arabinose, galactose, rhamnose, G, the ratio of arabinose and xylose and the molar percent of S and G had significant negative correlations with C6 production. While, there was no significant correlation between lignin and C6. Morever, we found 56 QTLs associated with the 32 cell wall relative traits. There was one quantitative trait loci effecting Ara/Xyl was located in chromose 11, explaining 10.30% of the total phenotypic variation. Three quantitative trait loci effects C5 production were located in chromose 8,8 and 9, explaining 6.19%,19.61% and 4.48% of the total phenotypic variation respectively. Three quantitative trait locus controled C6 production were located in chromose 6,8 and 9, explaining 4.32%,7.71%,6.57% of the total phenotypic variation respectively, one quantitative trait loci effects crystal cellulose was located in chromose 9, explaining 11.94% of the total phenotypic variation.This study have found some related factors affecting rice cell wall degradation, which figured out the direction of breeding energy crops and had the vital significance to guide the breeding of high efficiency as well as high yield energy rice variety.