Abstract: 【Objective】 To understand the diversity and ecological functions of alfalfa rhizosphere bacterial community structure in different planting areas in northern Xinjiang, and explore the effect of soil enzyme activity on alfalfa rhizosphere bacterial community structure. 【Methods】 In this study, high-throughput sequencing technology was used to study the diversity of bacterial community structure in the rhizosphere and non-rhizosphere soils of alfalfa in different planting areas in northern Xinjiang and the difference of bacterial community structure diversity between rhizosphere and non-rhizosphere soil and the relationship between bacterial community diversity and soil enzyme activity were compared; the ecological function of the corresponding bacterial community was obtained by using Tax4Fun function prediction. 【Results】 The enzymatic activity of rhizosphere soil in different planting areas in northern Xinjiang generally showed that rhizosphere was larger than non-rhizosphere, indicating that rhizosphere microorganisms played an important role in improving soil enzyme activity. In addition, there was a significant positive correlation between Alpha diversity index and soil neutral phosphatase (P<0.05) but no significant relationship with other soil enzyme activities, indicating that the characteristics of bacterial community structure and soil neutral phosphatase content were relevant. High-throughput sequencing technology was used to sequence microorganisms in alfalfa rhizosphere and non-rhizosphere soil, all 2581720 sequences belonged to 51 phyla, 64 phyla, 137 orders, 252 families and 600 genera of bacteria. At the phylum level, proteobacteria and actinobacteria were most abundant; at the genus level, 190 genera were shared by 12 soil sample types. Tax4Fun performed gene function prediction based on the SILVA database. The diversity of alfalfa bacterial community including the first functional layer was: environmental information processing, unclassified,organismal_systems, human disease, metabolism, genetic information processing, and cellular processes. 【Conclusion】 The change of bacterial diversity in the rhizosphere soil of alfalfa in different planting areas in northern Xinjiang is related to the content of soil neutral phosphatase. The microbial community composition is similar between rhizosphere and non-rhizosphere and different planting areas, but there are some differences in species diversity and ecological function of bacteria. The analysis of the above results provides important basic data for the distribution characteristics of alfalfa soil microorganisms in Xinjiang.

Key words: alfalfa; soil microorganisms; bacterial community diversity; bacterial function prediction

摘要： 【目的】研究新疆北部不同种植地苜蓿根际细菌群落结构多样性与生态功能,分析土壤酶活性对苜蓿根际细菌群落结构的影响,为新疆苜蓿土壤微生物的分布特征提供基础数据。【方法】使用高通量测序技术对新疆北部不同种植地苜蓿根际与非根际土壤细菌群落结构多样性进行研究,比较根际与非根际土壤细菌群落结构多样性差异及与土壤酶活性之间的关系;利用Tax4Fun功能预测获得相应样地的细菌群落的生态功能。【结果】新疆北部不同种植地苜蓿根际土壤酶活性大体表现为根际大于非根际,根际微生物在提高土壤酶活性中具有重要指示作用。Alpha多样性指数与土壤中性磷酸酶之间呈显著正相关性(P<0.05)而与其他土壤酶活性之间无显著性关系,细菌群落结构特征与土壤中性磷酸酶含量具有很强的相关性。利用高通量测序技术对苜蓿根际、非根际土壤中微生物进行测序,所有2581720条序列分属于细菌的51个门、64个纲、137目、252科和600属;所有土壤样品中在门水平上,变形菌门(Proteobacteria)和放线菌门(Actinobacteria)丰度最高;在属水平上其中12个土样类型共同拥有的有190个属。 Tax4Fun基于SILVA数据库进行基因功能预测,苜蓿根际细菌群落所涵盖的一级功能基因为:环境信息处理(Environmental_Information_Processing)、未分类(Unclassified)、生物体系统(Organismal_Systems)、人类疾病(Human_Diseases)、新陈代谢(Metabolism)、遗传信息处理(Genetic_Information_Processing)、细胞过程(Cellular_Processes)。【结论】新疆北部不同种植地苜蓿根际土壤细菌多样性改变与土壤中性磷酸酶含量有关,根际与非根际及不同种植地之间,微生物群落组成相似,但物种多样性、细菌的生态功能存在一定差异。

关键词: 苜蓿, 土壤微生物, 细菌群落多样性, 细菌功能预测