Turner P E, Burch C L, Hanley K A, Chao L
Department of Biology, University of Maryland, College Park, Maryland 20742, USA.
J Virol. 1999 Mar;73(3):2420-4. doi: 10.1128/JVI.73.3.2420-2424.1999.
Coinfection of the same host cell by multiple viruses may lead to increased competition for limited cellular resources, thus reducing the fitness of an individual virus. Selection should favor viruses that can limit or prevent coinfection, and it is not surprising that many viruses have evolved mechanisms to do so. Here we explore whether coinfection is limited in the RNA bacteriophage phi6 that infects Pseudomonas phaseolicola. We estimated the limit to coinfection in phi6 by comparing the frequency of hybrids produced by two marked phage strains to that predicted by a mathematical model based on differing limits to coinfection. Our results provide an alternative method for estimating the limit to coinfection and confirm a previous estimate between two to three phages per host cell. In addition, our data reveal that the rate of coinfection at low phage densities may exceed that expected through random Poisson sampling. We discuss whether phage phi6 has evolved an optimal limit that balances the costly and beneficial fitness effects associated with multiple infections.
多种病毒对同一宿主细胞的共感染可能导致对有限细胞资源的竞争加剧，从而降低单个病毒的适合度。自然选择应青睐那些能够限制或防止共感染的病毒，许多病毒已经进化出这样做的机制也就不足为奇了。在这里，我们探讨了感染菜豆假单胞菌的RNA噬菌体phi6中的共感染是否受到限制。我们通过比较两种标记噬菌体菌株产生的杂交体频率与基于不同共感染限制的数学模型预测的频率，来估计phi6中的共感染限制。我们的结果提供了一种估计共感染限制的替代方法，并证实了先前估计的每个宿主细胞中有两到三个噬菌体。此外，我们的数据表明，在低噬菌体密度下的共感染率可能超过随机泊松抽样预期的水平。我们讨论了噬菌体phi6是否已经进化出一个最佳限制，以平衡与多重感染相关的成本和有益的适合度效应。
