牛津大学的研究人员Michiel Vos发现，土壤中的噬菌体能够根据其周围细菌的类型而不断改进他们感染细菌的能力，因此，噬菌体的这种进化方式能够重构其生存的小范围内的生态系统。这篇研究报告发表在Science杂志上。
Michiel Vos在一块土地上选取5个点为土壤样本，每个样本土壤面积为25cm×25cm。然后从各个样本中分离出Stenotrophomas细菌及其相关的噬菌体。噬菌体对细菌进行感染，增殖，并导致细菌细胞破裂，然后噬菌体从一个细菌继续感染另一个细菌。研究人员发现，超过1/3的细菌对来自同一块土壤的噬菌体非常敏感，很容易被噬菌体感染。因而，噬菌体能够很快控制土壤细菌的种类。
在进一步的研究中Vos发现，噬菌体更容易感染来自同一块土壤的细菌，而对来自其他土壤样本中的细菌感染力相对较弱。进化生态学家称这是噬菌体的“局部适应性(locally adapted)”。
Vos及其同事的这项研究表明，即使在只有几平方厘米的小范围内，微生物种群的分布也不是随机的。噬菌体通常都分布在最易被它们感染的细菌的周围。这项研究还证实，土壤中各种不同类型的微生物间的相互作用在构成生物多样性上有非常重要的意义。（生物谷Bioon.com）
生物谷推荐原始出处：
Science 14 August 2009:DOI: 10.1126/science.1174173
Local Adaptation of Bacteriophages to Their Bacterial Hosts in Soil
Michiel Vos,1,*, Philip J. Birkett,1 Elizabeth Birch,1 Robert I. Griffiths,2 Angus Buckling1
Microbes are incredibly abundant and diverse and are key to ecosystem functioning, yet relatively little is known about the ecological and evolutionary mechanisms that shape their distributions. Bacteriophages, viral parasites that lyse their bacterial hosts, exert intense and spatially varying selection pressures on bacteria and vice versa. We measured local adaptation of bacteria and their associated phages in a centimeter-scale soil population. We first demonstrate that a large proportion of bacteria is sensitive to locally occurring phages. We then show that sympatric phages (isolated from the same 2-gram soil samples as the bacteria) are more infective than are phages from samples some distance away. This study demonstrates the importance of biotic interactions for the small-scale spatial structuring of microbial genetic diversity in soil.
1 Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
2 Centre for Ecology and Hydrology, Oxford OX1 35R, UK.
