| The plant cell wall has a unique structure,which is of great significance in the exploration of plant growth and development and biomass resources.The research on the synthesis and regulation pathways of cell wall components has gradually deepened,and exploring the utilization value of cell walls has become a research hotspot.The influence on breeding and production is also increasing.Rice is one of the important resources.The continuous maturation of current breeding and gene editing technologies helps to obtain plant varieties that can efficiently use straw without affecting yield.Related technical approaches are worth further discussion.In this study,rice cell walls obtained by different techniques were used to compare and improve the differences in their components,and to explore their positive effects on biomass utilization,providing a basis for agricultural production and utilization of biomass resources.1.Explored the differences in cell wall components of the progeny of indica-japonica hybrid inbred lines.In this experiment,the cellulose content of 85% of the samples was 30-50%,and the hemicellulose content of 86.85% of the samples was 10-20%.However,the number of samples with a lignin content of 15-25% is only 44%,indicating that the separation and variation range of lignin traits is wider.QTL correlation analysis showed that there were no obvious specific sites in several block intervals of cellulose and hemicellulose.Lignin analysis found that the lignin-related genes located in the block 107986-block108304 of chromosome 3(Chr3)in the rice genome.Among the 270 samples,11 block fragments were non-identical genotypes,accounting for only 3.31%;in the same genotype,the probability of homozygosity from the male parent was 12.87%,and the probability of homozygosity from the female parent was 83.82%.It means that the inheritance of indica-japonica hybrid rice in lignin regulation is more inclined to the female parent.In samples with extremely low lignin content,all genotypes at block 108165,block 108222,and block 108273 were only heterozygous.2.Uridine diphosphate xylose epimerase(UXE)and xylan arabinosyl transferase(XAT)are the key enzymes for arabinose-based biosynthesis and transfer to the xylan side chain,respectively.The UXE gene is ubiquitous in different species,and XAT in monocotyledonous plants is clustered in the same clade,indicating that XAT may have evolved a specific function in monocotyledonous plants.The cell wall morphology of uxe1xue2,uxe1uxe3 and xat2xat3 mutants(CRISPR / Cas9 pathway)did not change significantly.In the cell wall component,the amount of arabinose(Ara)in the uxe1xue2 and uxe1uxe3 mutants was reduced by 38.17% and 47.11%,respectively,the amount of arabinose(Ara)in the xat2xat3 mutant was reduced by 32.85%,and the amount of glucose content did not change.The results of 1H-NMR,2D-HSQC and FT-IR data show that the content of Ara sugar group in the mutant is reduced,and the degree of acetylation modification of hemicellulose is weakened.In addition,the mutants improved saccharification efficiency,of which the uxe1uxe2 mutant had the largest increase in saccharification efficiency,at 15.19%.Our results provide a new strategy for the utilization of rice straw.3.Explore and analyze the cell wall characteristics of tetraploid rice.The results showed that the cellulose content in the tetraploid straw increased,the cellulose crystallinity decreased,and the lignin content and S / G decreased.The surface analysis of the SEM image shows that the tetraploid straw is easier to pretreat.Tetraploid straw saccharification efficiency is higher,and its efficiency is up to 77.60%.The lignin content in the cell wall of the tetraploid rice straw is reduced,and the structural changes of the syringyl unit and the guaiacyl unit directly make the straw easier to be pretreated,thereby reducing the cost of pretreatment.In addition,the reduction of the cellulose crystallinity of the straw cell wall can further improve the utilization efficiency. |
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