| 基于分子生态学网络分析松嫩退化草地土壤微生物群落对施氮的响应 |
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| 引用本文： | 朱瑞芬,刘杰淋,王建丽,韩微波,申忠宝,辛晓平.基于分子生态学网络分析松嫩退化草地土壤微生物群落对施氮的响应[J].中国农业科学,2020,53(13):2637-2646. |
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| 作者姓名： | 朱瑞芬 刘杰淋 王建丽 韩微波 申忠宝 辛晓平 |
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| 作者单位： | 1黑龙江省农业科学院草业研究所,哈尔滨1500862中国农业科学院农业资源与农业区划研究所,北京100081 |
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| 基金项目： | 国家重点研发计划(2016YFC0500607-2);黑龙江省自然科学基金(YQ2019C019) |
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| 摘 要： | 【目的】 氮素输入影响着全球草地生态系统的可持续性,关注施氮对土壤微生物群落的影响及其分子生态网络,为草地退化修复提供理论依据。【方法】 以松嫩退化羊草草地为研究对象,通过施氮和未施氮处理,利用高通量测序和随机矩阵网络构建理论构建土壤微生物群落分子生态网络。探讨氮素管理对退化羊草草地土壤微生物群落结构及网络的影响,氮添加条件下微生物网络结构中的关键微生物变化规律,以及该过程中微生物之间的互作关系,解析外源氮素添加条件下土壤细菌动态变化的关键结点和规律。【结果】 在门分类水平上施氮处理草地有细菌门22个,未施氮处理23个。7个菌门是施氮和未施氮处理草地的优势菌门,其中变形菌门（Proteobacteria）是含有OTU数量最多的门类,约占总序列的30.46%,酸杆菌门（Acidobacteria）是含有OTU数量次之的门类,约占总序列的30.15%,芽单胞菌门（Gemmatimonadetes）是含有OTU数量第3的门类,约占总序列的8.14%,放线菌（Actinomycete）约占总序列的6.15%,绿弯菌门（Chloroflexi）、拟杆菌门（Bacteroidetes）和硝化螺旋菌门（Nitrospirae）三者约占总序列的17.16%。施氮处理草地土壤微生物中的变形菌门、放线菌门、拟杆菌门的相对丰度均显著高于未施氮处理草地土壤（P<0.01）;未施氮草地土壤中绿弯菌门、酸杆菌门、芽单胞菌门相对丰度显著高于施氮草地土壤（P<0.01）,其他各门细菌施氮与未施氮处理间未呈现出显著差异。表征网络的正向连接比、平均路径长度、平均聚类系数和模块性均为施氮处理显著低于未施氮处理（P<0.001）。在土壤的分子生态网络中,未施氮处理有16个模块枢纽（Zi>2.5,Pi≤0.62）,施氮处理有6个模块枢纽,均属于酸杆菌门、芽单胞菌门和放线菌门。施氮导致土壤微生物种间关系改变,进而改变土壤整体生态网络。【结论】 施氮降低了退化草地土壤网络结构的复杂程度和紧密性;降低了退化草地土壤中的酸杆菌门和绿弯菌门相对丰度,提高了变形菌门、放线菌门和芽单胞菌门相对丰度。土壤中微生物关键物种（OTU）由16个（未施氮）减少为6个,且二者土壤中均没有重叠OTU,这表明施氮调控微生物群落网络的关键物种,进而改变其分子生态网络结构。
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| 关 键 词： | 施氮 退化草地 土壤微生物 分子生态学网络 |
| 收稿时间： | 2019-09-10 |
Molecular Ecological Network Analyses Revealing the Effects of Nitrogen Application on Soil Microbial Community in the Degraded Grasslands |
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| ZHU RuiFen,LIU JieLin,WANG JianLi,HAN WeiBo,SHEN ZhongBao,XIN XiaoPing.Molecular Ecological Network Analyses Revealing the Effects of Nitrogen Application on Soil Microbial Community in the Degraded Grasslands[J].Scientia Agricultura Sinica,2020,53(13):2637-2646. |
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| Authors: | ZHU RuiFen LIU JieLin WANG JianLi HAN WeiBo SHEN ZhongBao XIN XiaoPing |
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| Institution: | 1Institute of Pratacultural Science, Heilongjiang Academy of Agricultural Sciences, Harbin 1500862Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081 |
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| Abstract: | 【Objective】 Nitrogen input affects the sustainability of the global grassland ecosystem. Paying attention to the soil microbial community and its molecular ecological network can provide a theoretical basis for grassland degradation restoration. 【Method】 Taking Songnen degraded Leymus chinensis grassland as the research object, the molecular ecological network of soil microbial community was constructed by applying high-throughput sequencing and random matrix network construction with and without nitrogen treatment. To explore the effects of nitrogen management on the soil microbial community structure and network in degraded Leymus chinensis grassland, the key microbial changes in the microbial network structure under the condition of nitrogen addition was studied, and the interaction between microorganisms during the process were investigated, and the conditions for external nitrogen addition key points and regularity of soil bacterial dynamic change were analyzed. 【Result】 At the level of phylum classification, there were 22 bacterial phylum in nitrogen-applied grassland and 23 without nitrogen. The 7 phylum were the dominant phylum of the nitrogen-applied and non-nitrogen-applied grasslands. Among them, Proteobacteria was the phyla containing the largest number of OTUs, accounting for about 30.46% of the total sequence. The next largest genus was about 30.15% of the total sequence. The genus Gemmatimonadetes was the third genus containing OTUs, accounting for 8.14% of the total sequence. Actinomycete accounted for about the total 6.15% of the sequence, while Chloroflexi, Bacteroidetes and Nitrospirae accounted for 17.16% of the total sequence. The relative abundances of Proteobacteria, Actinomycota and Bacteroides in soil microorganisms in nitrogen-applied grassland were significantly higher than those in non-nitrogen applied grassland soil; The relative abundances of Proteobacteria, Actinomycete and Bacteroidetes were significantly higher than the soils of nitrogen-applied grassland (P<0.01), and no significant difference was found between the nitrogen application and non-nitrogen treatment of other bacteria. The forward connection ratio, the average path length, the average clustering coefficient, and the modularity of the characterizing network were all significantly lower than the nitrogen-free treatment (P<0.001). In the molecular ecological network of soil, there were 16 modular hubs without nitrogen treatment (Zi>2.5, Pi≤0.62), and there were 6 modular hubs under nitrogen treatment, all of which belong to Acidobacteria, Gemmatimonadetes and Actinomycete. Nitrogen application led to changes in soil microbial species relationships, which in turn changed the overall soil ecological network. 【Conclusion】 Nitrogen application reduced the complexity and tightness of soil network structure of degraded grassland, and reduced the relative abundance of Acidobacteria and Chloroflexi in degraded grassland, while which improved the relative abundance of Proteobacteria, Actinomycete and Gemmatimonadetes. The number of microbial key species (OTU) in soil decreased from 16 (no nitrogen application) to 6 and there was no overlapping OTU in both soils, indicating that nitrogen application regulated key species of its community network and thus changes its molecular ecological network. |
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| Keywords: | nitrogen application degraded grassland soil microbe molecular ecology network |
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