Castledine Meaghan, Padfield Daniel, Schoeman Marli, Berry Amy, Buckling Angus
College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK.
Falmouth School, Trescobeas Rd, Falmouth TR11 4LH, UK.
Microbiology (Reading). 2025 Jun;171(6). doi: 10.1099/mic.0.001577.
Bacteriophages can be important drivers of bacterial densities and, therefore, microbial community composition and function. These ecological interactions are likely to be greatly affected by evolutionary dynamics because bacteria can rapidly evolve resistance to phage, while phage can reciprocally evolve to increase infectivity. Most studies to date have explored eco-evolutionary dynamics using isolated pairs of bacteria-phage, but in nature, multiple bacteria and phages coexist and (co)evolve simultaneously. How coevolution plays out in this context is poorly understood. Here, we examine how three coexisting soil bacteria ( sp., sp. and sp.) interact and evolve with three species-specific bacteriophages over 8 weeks of experimental evolution, both as host-parasite pairs in isolation and as a mixed community. Across all species, phage resistance evolution was inhibited in polyculture, with the most pronounced effect on . Between bacteria-phage pairs, there were also substantial differences in the effect of phage on host densities and evolutionary dynamics, including whether pairs coevolved. Our results also indicate bacteria have a relative advantage over phage, with high rates of phage extinction and/or lower densities in polyculture. These contrasts emphasize the difficulty in generalizing findings from monoculture to polyculture and between model bacteria-phage pairs to wider systems. Future studies should consider how multiple bacteria and phage pairs interact simultaneously to better understand how coevolutionary dynamics happen in natural communities.
噬菌体可能是细菌密度的重要驱动因素，因此也是微生物群落组成和功能的重要驱动因素。这些生态相互作用可能会受到进化动态的极大影响，因为细菌能够迅速进化出对噬菌体的抗性，而噬菌体也能相应地进化以提高感染力。迄今为止，大多数研究都是使用分离的细菌-噬菌体对来探索生态进化动态，但在自然界中，多种细菌和噬菌体同时共存并（共同）进化。在这种情况下，协同进化是如何发生的，目前还知之甚少。在这里，我们研究了三种共存的土壤细菌（ 种、 种和 种）如何在8周的实验进化过程中与三种物种特异性噬菌体相互作用并进化，实验中既有作为分离的宿主-寄生对，也有作为混合群落的情况。在所有物种中，混养时噬菌体抗性进化受到抑制，对 种的影响最为显著。在细菌-噬菌体对之间，噬菌体对宿主密度和进化动态的影响也存在很大差异，包括这些对是否共同进化。我们的结果还表明，细菌相对于噬菌体具有相对优势，在混养中噬菌体灭绝率高和/或密度较低。这些差异强调了将单培养的研究结果推广到混培养以及将模型细菌-噬菌体对的研究结果推广到更广泛系统的困难。未来的研究应该考虑多种细菌和噬菌体对如何同时相互作用，以便更好地理解自然群落中协同进化动态是如何发生的。
