四川盆地紫色土中丰富及稀有细菌的分布特征与动态变化

Distribution Characteristics and Dynamics of Abundant and Rare Bacteria in Purple Soil of the Sichuan Basin

土壤微生物群落由少数丰富类群和多数稀有类群组成,揭示丰富和稀有细菌的分布特征和动态变化对于理解土壤生态系统至关重要。本研究以旱地紫色土为研究对象,以猪粪和鸡粪为有机肥的外源,进行为期100 d的培养试验,并设计5个采样时间点,采用高通量测序技术,对不施肥对照处理(CK),施加猪粪处理(PMS),施加鸡粪处理(CMS)紫色土中细菌群落进行分析。结果表明:稀有细菌的数量、分类群以及α多样性指数高于丰富细菌,说明两者的分布组成存在差异。丰富和稀有细菌群落结构具有相似的动态变化,施用猪粪对微生物群落结构的影响异于未施肥和施鸡粪处理。共现网络分析显示稀有细菌的拓扑特性显著高于其他类群,但少数丰富细菌占据了网络的中心节点。条件稀有或丰富细菌具有高度中介中心性,表明其在群落动态变化中存在一定贡献。研究结果有助于理解施用粪肥土壤中细菌群落的动态变化及其生态网络。

Soil microbial community is composed of a few abundant taxa and most rare taxa,and revealing the distribution characteristics and dynamic changes of abundant and rare bacteria is essential for understanding soil ecosystem.In this study,the purple soil of dryland was subjected to a 100-day incubation experiment with pig manure and chicken manure as the external source of organic fertilizer,and five sampling time points were designed to analyze the bacterial communities in the purple soil of no fertilizer control treatment(CK),pig manure application treatment(PMS)and chicken manure application treatment(CMS)by using highthroughput sequencing technology.The results showed that the number,taxa andαdiversity index of rare bacteria were higher than those of abundant bacteria,indicating that the distribution composition of the two bacteria was different.The dynamic changes of abundant and rare bacterial community structure were similar,and the effects of pig manure application on microbial community structure were different from those of unfertilized and chicken manure treatments.Co-occurrence network analysis showed that the topological characteristics of rare bacteria were significantly higher than other groups,but a few abundant bacteria occupied the central nodes of the network.Condition rare and abundant taxa had high betweeness centrality,indicating their contribution in the community dynamics.The results of this study are helpful to understand the dynamic changes of bacterial community and their ecological network in the soil applied with manure.