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通过玉米盆栽试验研究不同水分条件下(土壤孔隙含水量20%和80%)土壤微生物群落结构及种群数量的变化。采集玉米生长第60天时的根际土和表层土,通过Mi Seq Illumina高通量测序技术扩增细菌和古菌16S r RNA基因分析群落多样性,同时通过绝对定量PCR扩增细菌和古菌16S r RNA基因分析其种群数量。结果表明:高通量测序共得到41 546个细菌OTUs和6 921个古菌OTUs。土壤中细菌的多样性丰富,优势菌群为变形菌(Proteobacteria)和酸杆菌(Acidobacteria),而古菌的群落组成单一,优势菌群为奇古菌(Thaumarchaeota)。非度量多维尺度(NMDS)分析表明不同土壤区域中细菌群落结构具有明显差异,而古菌群落结构受水分和土壤区域的影响不明显。定量分析结果显示细菌和古菌数量受土壤区域和水分条件的影响显著。表层土中细菌和古菌数量均显著高于根际土。根际土中细菌和古菌数量在水分充足条件下均显著高于干旱条件,表层土中细菌和古菌数量也表现出相同趋势。本研究结果表明土壤不同区域(生态位)可能是影响土壤中微生物群落最重要的因素。
The pot experiment was conducted to study the changes of soil microbial community structure and population under different water conditions (20% and 80% of soil pore water content). Rhizosphere soil and topsoil at the 60th day of maize growth were collected, and the diversity of 16S rRNA gene of bacteria and archaea was amplified by MiSeq Illumina high-throughput sequencing. Meanwhile, the bacterial and archaeal 16S were amplified by absolute quantitative PCR r RNA gene analysis of its population. The results showed that 41 546 bacterial OTUs and 6 921 archaeal OTUs were obtained by high-throughput sequencing. The bacteria in the soil is rich in diversity. The dominant bacteria are Proteobacteria and Acidobacteria, while the archaeal community has a single species and the dominant species is Thaumarchaeota. Non-metric multidimensional (NMDS) analysis shows that there are significant differences in bacterial community structure in different soil regions, whereas archaeal community structure is not significantly affected by water and soil regions. Quantitative analysis showed that the number of bacteria and archaea was significantly affected by soil regions and moisture conditions. The number of bacteria and archaea in surface soil were significantly higher than rhizosphere soil. The number of bacteria and archaea in the rhizosphere soil was significantly higher than that in the drought condition with adequate water content, and the same trend was observed in the number of bacteria and archaea in the topsoil. The results of this study indicate that different regions of the soil (niche) may be the most important factor affecting soil microbial community.