CRISPR/Cas9编辑DTH8基因改良优质稻大粒香抽穗期OA

[Objective]The DTH8 gene in rice was modified by using CRISPR/Cas9 gene editing technology to shorten the growth period of Dalixiang(a high-quality rice variety)without influencing its excellent agronomic traits and provide a new strategy for improvement of rice varieties.[Method]Taking the high-quality rice variety Dalixiang from Guizhou as the material,specific sgRNAs targeting functional domains of DTH8 were designed by using CRISPR/Cas9 gene editing technology and introduced into Dalixiang calli via agrobacterium-mediated transformation.The mutant rice plants were sequenced and identified after PCR screening.The exogenous genes of the positive rice plants were eliminated and screened to obtain the transgene-free homozygous lines.The agronomic traits of heading date,thousand-grain weight,grain shape,milled rice rate,chalkiness rate,yield per plant and seed-setting percentage of wild and mutant rice plants were determined.[Result]Four independent T0 positive transgenic lines without exogenous genes were successfully obtained and bred.Two transgene-free homozygous mutants(J1186-2-2 and J1186-25-1)were isolated by PCR amplification and sequencing.The heading date of J1186-2-2 and J1186-25-1 was 6 d and 5 d earlier than the wild type respectively and their rice quality was no significant variation.The yield and seed-setting percentage of J1186-25-1 increased by 5.55%and 3.63%,but the yield and seed-setting percentage of J1186-2-2 decreased by 8.77%and 8.56%.[Conclusion]The CRISPR/Cas9-edited DTH8 gene can effectively shorten the heading date of mutant plant J1186-2 and J1186-25-1 of Dalixiang with a stable rice quality.