为弄清茅贡米土壤微生物群落结构和生物固氮等代谢活动机制,采用试剂盒、SDS高盐和土壤预处理+SDS高盐3种土壤DNA提取方法,以从贵州茅贡米基地采集的土样提取的宏基因组DNA为模板,进行nifA基因的PCR扩增,比较了3种土壤DNA提取方法的效果。结果表明,试剂盒提取的DNA扩增到约200bp和900bp的nifA基因片段,SDS高盐法、预处理+SDS高盐法提取的DNA仅扩增到约200bp的nifA基因片段,土壤预处理对提高DNA纯度有一定的效果;3种方法都可以从土壤中提取到约23kb大小的DNA片段,但DNA得率和纯度存在一定的差异。 In order to understand the metabolic activity mechanism of soil microbial community structure and biological nitrogen fixation in Maogongmi, three soil DNA extraction methods, including kits, SDS high salt and soil pretreatment + SDS high salt, The extracted macrogenomic DNA was used as a template to amplify the nifA gene. The effects of three soil DNA extraction methods were compared. The results showed that the DNA extracted from the kit was amplified to nifA gene fragments of about 200bp and 900bp. The DNA extracted from SDS high salt and pretreatment + SDS high salt method only amplified nifA gene fragment of about 200bp. Improve DNA purity have certain effect; 3 kinds of methods can be extracted from the soil about 23kb DNA fragments, but the yield and purity of DNA there is a certain difference.