不同采样策略影响土壤捕食线虫真菌物种多样性检测结果

Sampling strategy influences the detection results of the diversity of soil nematode-trapping fungi species

摘要:

【背景】土壤微生物多样性是土壤学领域的研究前沿和热点，而科学的土壤样品采集策略是保证研究结果真实性的重要保障。【目的】探究不同采样策略对土壤捕食线虫真菌(nematode-trapping fungi，NTF)纯培养检测结果的影响。【方法】对3个不同生境样方的土壤进行不同样点数(3点、5点、9点和13点)、不同样点空间排布(一字型、V型、W型、三角型和梅花型)的土壤混合及不混合采样，以单孢子分离法纯化NTF，结合形态和分子技术鉴定物种，分析比较不同样点数、不同样点空间排布的土壤混合及不混合采样策略下NTF的α多样性及检出菌株数的差异。【结果】在单点采样、分别纯化、合并分析各点检测数据策略下，NTF的α多样性和检出菌株数随着合并样点数的增加而增高，5个点或9个点的不同整合数据间差异较小，检测结果相对较稳定。在土壤混合采样策略下，超过5个点土样混合不利于NTF的检测。【结论】土壤样品采集策略影响NTF纯培养结果。在单点采样、数据合并分析策略下，5点或9点采样法相对更好；土壤混合采样策略下，5点采样混合法相对更科学和可行。

Abstract:

[Background] Soil microbial diversity has become the research frontier and hot spot in soil science, and science-based soil sampling is the prerequisite for accurate research result. [Objective] To explore the influence of sampling strategy on the detection result of soil nematode-trapping fungi (NTF) and to seek for scientific soil sampling method.[Methods] Soils were collected from different number of sampling sites (3, 5, 9 and 13) which were indifferent arrangements (straight line, V-shaped, W-shaped, triangle-like, and plum blossom-like) in 3 habitats and they were either mixed or unmixed for detection. NTF were purified by single spore isolation. The species were identified based on morphological observation and molecular techniques, and the difference in species diversity and species number of NTF among soils collected with different methods was analyzed. [Results] In the case of single-site sampling, separate purification, and integrated analysis, the α diversity and the number of detected strains rose with the increase in the integrated sampling sites. The difference in the integrated data of 5 and 9 sites was small and the detection results were relatively stable. In the instance of mixing of soil from different sites and then purification, the mixing of soil from more than 5 sites was not conducive to the detection of NTF. [Conclusion] Soil sampling strategy affects pure culture results of NTF. In the case of single-site sampling, separate purification, and integrated data analysis, the 5-site or 9-site sampling is optimal. As for the strategy of soil mixing first and then purification, the 5-site sampling is relatively scientific and feasible.