不同土壤采样设计下土壤表层微生物α多样性的差异分析

【背景】土壤采样是土壤研究的基础,采样方案的不同可能会对土壤微生物多样性的研究结果产生一定影响。【目的】研究不同的土壤采样设计方案对土壤样品16S rRNA基因高通量测序结果的影响。【方法】对2个不同生境样地的土壤进行网格化采样,对采集的18个土壤样品进行16S rRNA基因测序分析,通过模拟5种常见土壤采样方法,对比不同采样方式所获得的测序结果。【结果】不同采样方式会产生不同的测序结果。在测序深度有效的情况下,细菌总物种数随着采样数的增加而逐渐增长,增长速度在采样数大于5以后趋于平缓;样品中的优势物种(序列数200以上)只需很少的采样数(1-3)即可观察到全部物种;Shannon-Wiener指数与Simpson指数的变化较相似,当采样数由1到3时两指数均有较大增长,之后变化放缓。【结论】土壤细菌微生物测序研究中,土壤样地采样数量低于3个会影响测序结果的可靠性,采样方案选择梅花形采样法或蛇形采样法较为适宜。

Effect of soil sampling designs on soil microbial alpha diversity

[Background] Soil sampling is the basis of soil research, and different sampling designs can have a considerable impact on the results of soil microbial research. [Objective] To investigate the effects of different soil sampling designs on microbial community structure and diversity of soils obtained through 16S rRNA gene high-throughput sequencing. [Methods] In this study, soils from two different habitats were sampled by grid sampling method, and all the 18 soil samples were analyzed by 16S rRNA gene high-throughput sequencing. Five common soil sampling methods were simulated through combining different points from the sampling grids. The sequencing results of different sampling methods were simultaneously compared. [Results] Different sampling methods resulted in different soil microbial sequencing results. The number of bacterial species gradually increased with the increased of numbers of samples, and the growth rate would be gentle when numbers of samples were greater than 5; dominant species (more than 200 sequences) could be wholly observed in few numbers of samples (1?3).; the Shannon-Wiener index and Simpson index were similar, when the numbers of samples was from 1 to 3, both indices increased significantly, then it slowed down. [Conclusion] In the study of soil bacterial microbial sequencing, numbers of soil samples below 3 would affect the reliability of sequencing results. Comparison of the sampling methods, Quincunx sampling or serpentine sampling method is more suitable for soil sampling design.