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为早期鉴定晒烟TMV抗性,寻找抗TMV优良品种,试验以“吉烟九号”DNA为模板,选用1对N基因特异性引物,采用25 μL PCR反应体系,对影响N基因的SSR-PCR反应体系的主要因子进行单因素优化,用所优化的体系对7对N基因特异性引物和25个烟草品种进行SSR-PCR扩增,并结合25个烟草品种的人工接种抗性鉴定结果,验证体系的稳定性和可靠性.试验结果表明:烟草N基因SSR-PCR最适反应条件为25 μL体系中含20 ng/μ L模板DNA,0.20 μmol/L引物,1.5 mmol/L Mg2+,0.20 mmol/LdNTPs,1.0 U Taq酶.由分子标记鉴定和人工鉴定结果可知,凡能扩增出特异性条带的品种,其人工抗性鉴定为TMV免疫.由此可见,N基因分子标记抗性鉴定与人工接种鉴定结果吻合,说明SSR分子标记鉴定N基因控制的烟草TMV抗性方法科学可靠,可以作为早期鉴定TMV抗性的有效辅助手段.“,”To screen elite tobacco varieties resistant to TMV by early identification with PCR technique,using genomic DNA from Jiyan No.9 as template,with one pair of N gene specific primers in 25 μL wells,single factor optimization of the major factors affecting N gene PCR reaction system was conducted.Subsequently,the stability and reliability of the optimized PCR system were confirmed using 7 pairs of specific primers of the N gene and 25 tobacco varieties combined with identifications by artificial inoculations.The results showed that the optimum SSR-PCR reaction conditions for screened SSR markers specific to tobacco N gene were 20 ng/L of DNA template,0.20 μmol/L of primers,1.5 mmol/L of Mg2+,0.20 mmol/L of dNTPs and 1.0 U Taq polymerase in 25 μL wells.The PCR amplification combined with the identification by artificial inoculation revealed that all the varieties were identified to be immune to TMV produced specific PCR bands,indicating that the results by PCR using N gene specific primers agreed with artificial inoculation identifications of suncured tobacco resistance to TMV.The PCR identification of tobacco TMV resistance controlled by N gene is scientific and reliable,and could be used as assistant means for early identification of tobacco resistance to TMV.