Evans J, Barnet Y M, Vincent J M
Can J Microbiol. 1979 Sep;25(9):968-73. doi: 10.1139/m79-148.
The presence of a virulent bacteriophage in the root zone of clover growing in seedling agar under controlled environments (14--17 and 19--23 degrees C) produced changes in the persistence and symbiotic effectiveness of a susceptible strain of Rhizobium trifolii. The phage reduced the rhizoplane population of rhizobia and led to the appearance of variant substrains which were less susceptible to the bacteriophage and mostly ineffective in symbiotic nitrogen fixation. Some were also changed in colonial morphology and nutritional requirements. At the higher temperature, the frequency of bacterial variants increased and the number of nodules due to the parent strain decreased. A large initial population of bacteriophage was able to reduce, but generally did not completely suppress, nodulation.
在可控环境（14 - 17摄氏度和19 - 23摄氏度）下，在幼苗琼脂中生长的三叶草根部区域存在一种烈性噬菌体，这导致了三叶草根瘤菌敏感菌株在持久性和共生有效性方面发生变化。噬菌体减少了根瘤菌在根际的数量，并导致出现对噬菌体不太敏感且大多在共生固氮中无效的变异亚菌株。一些亚菌株在菌落形态和营养需求方面也发生了变化。在较高温度下，细菌变异体的频率增加，亲本菌株形成的根瘤数量减少。大量初始噬菌体种群能够减少，但通常不会完全抑制结瘤。
