由于技术手段的限制，传统上人们往往认为微生物的地理分布与大型动植物的分布有着根本区别，即微生物是全球性随机分布的。随着分子生物学技术在微生物生态学研究中的应用，近年来发现土壤微生物群落结构和多样性同样具有一定的地理分布格局，颠覆了人们传统上对于微生物全球性随机分布的认识。这些研究证明了微生物的分布在空间上是非随机的，却仍没有回答微生物的这种非随机分布是如何产生和维持的，即哪些因子驱动了微生物多样性的空间分布特征。
近日，中科院生态环境研究中心贺纪正课题组有关大尺度下土壤微生物多样性变化驱动机制的研究取得重要成果，论文发表于Nature系列杂志《国际微生物生态学会会刊》（The ISME Journal）上（Differences in soil bacterial diversity: driven by contemporary disturbances or historical contingencies? The ISME Journal (2008) 2, 254–264）。
他们采用分子生物学技术，结合先进的统计分析方法，对大量土壤样品细菌多样性特征进行了系统分析，发现历史进化（以地理上分隔的不同取样点或土壤类型、土壤剖面层次来表征）是驱动大尺度下（约1000公里）土壤细菌多样性变化的主控因子，其对土壤细菌多样性变化的贡献约为60%；当代环境扰动（以不同的取样时间和施肥处理来表征）也可造成局部土壤细菌多样性变化，其对土壤细菌多样性变化的贡献约为20%；另有约20%的贡献来自于该研究尚未考察到的因子。这一研究首次在大尺度下对土壤细菌多样性的变化给出了定量表征，并为开展类似的土壤微生物生物地理学研究提供了方法思路。该项研究成果表明，历史进化和现代环境扰动对土壤细菌多样性变化的作用模式与大型动植物有相似之处，可能有一些对所有类型生物都适用的生物地理分布规律存在。
贺纪正研究员为中国科学院“引进国外杰出人才”计划入选者，2005年到生态环境研究中心组建“土壤分子生态学”课题组。该项研究受到科技部“973计划”、国家自然科学基金和科学院知识创新方向性项目的支持。（来源：中科院生态环境研究中心）
生物谷推荐原始出处：
（The ISME Journal），(2008) 2, 254–264，Yuan Ge，Ji-zheng He
Differences in soil bacterial diversity: driven by contemporary disturbances or historical contingencies?
Yuan Ge1,2, Ji-zheng He1, Yong-guan Zhu1, Jia-bao Zhang3, Zhihong Xu4, Li-mei Zhang1 and Yuan-ming Zheng1
Abstract
Contemporary environmental disturbances and historical contingencies are considered to be major factors driving current differences in microbial diversity. However, little was known about their relative importance. This study combines culture-independent molecular techniques and advanced statistical analyses to examine quantitatively the relative importance of contemporary disturbances and historical contingencies in influencing large-scale soil bacterial diversity using a large set of manipulated field-based molecular data (212 samples). Contemporary disturbances were represented by applications of different fertilizers N, P, K and organic manure (OM) and historical contingencies by distinct geographic sampling locations and soil profiles. Multivariate regression tree (MRT) analysis showed that diversity estimates were mainly distinguished by sampling locations, which explained 40.8% of the variation in bacterial diversity, followed by soil profiles (19.5%), sampling time (13.1%), OM (3.7%) and P (1.8%). Aggregated boosted tree (ABT) analysis showed that the relative importance of different categorical factors on soil bacterial diversity variation was ranked as sampling locations, soil profiles, sampling time, OM and P. Both MRT and ABT analyses showed that historical contingencies were the dominant factor driving variation in bacterial diversity across a regional scale (about 1000 km), whereas some contemporary disturbances also caused variation in bacterial diversity at a local scale. This study demonstrated that past events and contemporary disturbances had similar influence on soil bacterial diversity to that documented for macroorganisms, indicating that there might be some common aspects of biogeography to all organisms.
