敲除Bsr-d1和Pi21基因改良优良食味粳稻南粳9108的稻瘟病抗性研究OA北大核心CSTPCD

Rice blast,caused by Magnaporthe oryzae,is a one of serious diseases in rice,causing huge yield loss and bad quality annually.Breeding rice variety with broad spectrum and durable resistance to blast is the most economical and effective approach to control the disease.In this study,CRISPR/Cas9 technology was used to knock out Bsr-d1 and Pi21 genes,two quantitative resistance genes to blast,in a blast susceptible variety of Nanjing 9108,a well-known japonica rice variety with good taste in Jiangsu province.The homozygous knockout lines for each of the two genes were obtained,and through pyramiding,a double gene knockout line was developed either.Results of spraying inoculation in seedling stage and leaf scratch inoculation with multiple strains showed that,compared with the wild type,knockout lines of either Bsr-d1 or Pi21 all significantly enhanced blast resistance.Resistance levels of double-gene knockout lines were generally stronger than those of the individual gene knockout lines.RT-qPCR results showed that the expression levels of several defense-related genes were significantly higher in knockout lines than those of in wild type.Compared with the wild type,bsr-d1 and pi21 knockout lines showed no significant differences on major agronomic,economic and quality related traits.The new developed lines with enhanced blast resistance are of great value for further breeding new japonica rice varieties towards broad-spectrum and durable resistance to blast and good eating quality.