摘要
【目的】将稀有和丰富细菌亚群落从整体群落中加以区分并探索两者分别对长期施肥的响应特征,为解析农业活动对微生物多样性与土壤功能稳定性之间的关系提供新视角。【方法】基于设施番茄长期定位试验,采集4个不同处理土壤样品:不施肥(M0)、低量有机肥5.68 t·hm^(-2)(M1)、中量有机肥8.52 t·hm^(-2)(M2)和高量有机肥11.36 t·hm^(-2)(M3),利用Illumina MiSeq高通量测序技术,分析稀有和丰富细菌亚群落多样性、群落组成、共现网络和潜在功能差异,阐明两者对长期施肥的响应规律,并探讨驱动稀有和丰富细菌亚群落多样性和施肥响应差异的关键环境因素。【结果】稀有细菌亚群落α和β多样性均显著高于丰富细菌亚群落,且物种组成和潜在功能也与丰富细菌差异明显。功能预测结果显示丰富细菌负责设施农田主要生态系统功能,如养分和能量代谢,而稀有细菌更多体现在辅助功能上(例如辅酶代谢),为微生物群落功能冗余做出贡献。不同细菌亚群落多样性和组成对长期施肥响应差异较大,其中,与不施肥相比,长期施用有机肥和化肥使稀有细菌亚群落丰富度显著提高19.8%—53.8%、多样性显著提高5.8%—8.0%,总相对丰度显著提高1.1—1.2倍,改变稀有细菌亚群落组成和结构,并且随着有机肥施用量增加,稀有细菌丰富度显著提升,亚群落组成和结构也发生显著变化;与之相比,长期施肥并未显著改变丰富细菌亚群落多样性,仅群落组成受到影响。同时,细菌共现性网络复杂度随有机肥施用显著增加,且稀有细菌更敏感。非度量多维度分析(NMDS)和Mantel检验结果均显示,影响稀有和丰富细菌亚群落的关键环境因子不同,其中,土壤有机质、全量氮磷有效磷、速效钾、pH、大中团聚体等多种与确定性过程相关的土壤因子显著影响丰富细菌亚群落,结构方程模型(SEM)进一步显示土壤有机质和全磷直接驱动丰富细菌多样性变化;而稀有细菌亚群落受环境过滤的影响程度明显下降,且群落分散性更强,暗示两种亚群落构建机制可能存在差异。【结论】与丰富细菌和整体群落相比,稀有细菌亚群落呈现更高的多样性和独特的群落组成,提高微生物群落功能冗余;长期施肥主要通过影响稀有细菌(即提高多样性、改变群落组成、增加网络复杂度)而非丰富细菌,从而改变细菌整体群落,并且介导稀有和丰富细菌亚群落构建的环境因素也不相同。
【Objective】The objective of the present study was to distinguish the rare and abundant bacteria from the whole community and to explore their responses to long-term application of organic fertilizer respectively,so as to provide new insights into the relationships between soil biodiversity and ecosystem functioning under major agricultural activities.【Method】Based on the long-term fertilization experiment of greenhouse tomato,soils were collected under four different treatments,including no fertilizer(M0),low organic fertilizer 5.68 t·hm-2(M1),medium organic fertilizer 8.52 t·hm-2(M2),and high organic fertilizer 11.36 t·hm-2(M3).Illumina MiSeq platform was used to analyze the diversity,community composition,co-occurrence network and potential functions differences of the rare and abundant bacterial sub-communities,and their various responses to long-term fertilization,to illustrate the key factors driving the distinct distribution patterns and responses for rare and abundant bacteria.【Result】Compared with the abundant bacterial sub-community,the rare bacterial sub-community showed higherα-andβ-diversity and distinct community composition,as well as potential functions.A functional prediction detected that abundant bacteria contributed primary functions in the greenhouse ecosystem,such as nutrient and energy metabolism,meanwhile rare bacteria contribute a substantial fraction of auxiliary functions(e.g.,metabolism of cofactors),which indicated they played important roles in the functional redundancy of microbial communities.Contrasting responses of rare and abundant bacterial sub-communities to long-term fertilization were revealed in this study,in which the rare bacteria was more sensitive.Compared with no fertilizer,the long-term application of organic and chemical fertilizer significantly increased the OTU richness,Shannon diversity,and total relative abundance by 19.8%-53.8%,5.8%-8.0%,and 1.1-1.2 times,respectively,and changed the community composition and structure of rare bacterial sub-communities.In addition,with the increased application rates of organic fertilizer,the OTU richness of rare bacteria also increased significantly,accompanied by obvious changing in community composition and structure.However,the abundant bacteria exhibited less sensitivity to long-term fertilization,with only the community composition altered.Besides,the co-occurrence network complexity increased with organic fertilizer rates,especially in rare sub-communities.Both the results of the NMDS and mantel test revealed that the controlling factors affecting rare and abundant bacterial sub-communities were different.A variety of soil factors associated with deterministic processes,i.e.,SOC,soil nutrients of total N and P,Olsen-P and available K,and pH,as well as macro-and medium-aggregate,significantly influenced abundant bacteria.Structural equation model(SEM)further showed that soil organic matter and total phosphorus directly drove abundant bacterial diversity.On the other hand,less effects of environmental filtering and more scattered distribution patterns were found in rare bacteria,indicating different assemblies of rare and abundant sub-communities.【Conclusion】Compared with the abundant bacteria and the whole community,the rare bacteria sub-community showed higher diversity and unique community composition,which improved the functional redundancy of the microbial community.Long-term fertilization altered the whole bacterial community mainly by affecting rare bacteria(i.e.,increasing diversity,changing community composition,increasing co-occurrence network complexity)rather than the abundant bacteria.The controlling factors that mediated the assembly of the rare and abundant bacterial sub-communities were also different.
作者
刘蕾
史建硕
张国印
郜静
李玭
任燕利
王丽英
LIU Lei;SHI JianShuo;ZHANG GuoYin;GAO Jing;LI Pin;REN Yanli;WANG LiYing(Institute of Agricultural Resources and Environment,Hebei Academy of Agriculture and Forestry Sciences/Hebei Fertilizer Technology Innovation Center,Shijiazhuang 050051)
出处
《中国农业科学》
CAS
CSCD
北大核心
2023年第18期3615-3628,共14页
Scientia Agricultura Sinica
基金
河北省重点研发计划项目重大专项(21326904D)
河北省农林科学院科技创新专项(2022KJCXZX-ZHS-1)。
关键词
稀有细菌
丰富细菌
有机肥
设施番茄
多样性
群落构建
生态系统功能
rare bacteria
abundant bacteria
organic fertilizer
greenhouse tomato
diversity
community assembly
ecosystem function
