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【目的】为评价转基因棉花的种植对根际土壤反硝化细菌丰度和多样性的影响,【方法】以转Bt+CpTI基因抗虫棉(SGK321)及非转基因亲本棉花石远321(SY321)根际土壤反硝化细菌为研究对象,分别在种植前和棉花的不同生长时期(蕾期、花期、铃期和絮期)取样。采用实时荧光定量PCR方法和末端标记限制性片段多态性(T-RFLP)技术对土壤中反硝化细菌的功能基因nosZ基因进行定量和多样性分析。【结果】结果发现随棉花不同生长时期两种棉花根际土壤中的反硝化细菌丰度均发生显著变化,但变化趋势不同。转基因棉花根际土壤反硝化细菌从种植前的3.12×106copies/g dry soil一直增加到铃期的2.81×107copies/g dry soil,增加了8倍。非转基因棉花根际土壤反硝化细菌丰度变化受生长周期影响更为显著,表现为蕾期增加,花期降低,铃期又增加的趋势。典范相关及部分典范相关分析反硝化细菌多样性结果表明其多样性受环境因素pH、硝酸根浓度以及棉花生长时期(蕾期和花期)影响最为显著,但此外棉花品种也起到了非常重要的作用,【结论】反硝化细菌的丰度和多样性既受棉花生长时期的影响,同时也受棉花品种的影响,转基因棉花通过调节根际土壤中的pH和硝酸根浓度,来影响其多样性和丰度。转Bt+CpTI基因抗虫棉的种植增加了土壤pH,从而导致根际土壤反硝化细菌的多样性和丰度增加。
【Method】 The objective of this study was to evaluate the effects of transgenic cotton planting on the abundance and diversity of denitrifying bacteria in rhizosphere soils. 【Method】 The transgenic Bt + CpTI transgenic cotton (SGK321) The rhizosphere soil denitrifying bacteria was the object of study, and was sampled before planting and at different growth stages of cotton (bud, florescence, boll and floc). The quantitative and diversity analysis of the nosZ gene of denitrifying bacteria in soil was carried out by real-time fluorescence quantitative PCR and end-labeling restriction fragment polymorphism (T-RFLP). 【Result】 The results showed that the denitrifying bacteria abundance changed significantly in both cotton rhizosphere soils at different growth stages, but the changing trend was different. The rhizospheric soil denitrifying bacteria in transgenic cotton increased from 3.12 × 106copies / g dry soil before planting to 2.81 × 107copies / g dry soil in the boll stage, an increase of 8 times. The change of denitrifying bacteria abundance in rhizosphere soil of non-transgenic cotton was more significantly affected by the growth cycle, which showed that the budding stage increased, the flowering stage decreased and the boll stage increased again. Canonical Correlation and Partial Canonical Correlation Analysis The diversity of denitrifying bacteria showed that the diversity was most significantly influenced by pH, nitrate concentration and cotton growth stage (bud stage and flowering stage), but cotton variety also played a very important role 【Conclusion】 The abundance and diversity of denitrifying bacteria are influenced not only by the cotton growth period but also by the cotton varieties. The transgenic cotton affects its diversity and nitrate concentration by adjusting the pH and nitrate concentration in the rhizosphere soils Abundance. Planting of Bt + CpTI-resistant cotton increased soil pH, resulting in increased diversity and abundance of denitrifying bacteria in rhizosphere soil.