Centro de Estudios Científicos, Valdivia, Los Rios, Chile.
Department of Biology, Indiana University, Bloomington, Indiana, USA.
mSphere. 2020 Nov 11;5(6):e00975-20. doi: 10.1128/mSphere.00975-20.
Natural transformation is a broadly conserved mechanism of horizontal gene transfer (HGT) in bacteria that can shape their evolution through the acquisition of genes that promote virulence, antibiotic resistance, and other traits. Recent work has established that neighbor predation via type VI secretion systems, bacteriocins, and virulent phages plays an important role in promoting HGT. Here, we demonstrate that in chitin estuary microcosms, K139 lysogens exhibit prophage-dependent neighbor predation of nonlysogens to enhance HGT. Through predation of nonlysogens, K139 lysogens also have a fitness advantage under these microcosm conditions. The ecological strategy revealed by our work provides a better understanding of the evolutionary mechanisms used by bacteria to adapt in their natural setting and contributes to our understanding of the selective pressures that may drive prophage maintenance in bacterial genomes. Prophages are nearly ubiquitous in bacterial species. These integrated phage elements have previously been implicated in horizontal gene transfer (HGT) largely through their ability to carry out transduction (generalized or specialized). Here, we show that prophage-encoded viral particles promote neighbor predation leading to enhanced HGT by natural transformation in the waterborne pathogen Our findings contribute to a comprehensive understanding of the dynamic forces involved in prophage maintenance which ultimately drive the evolution of naturally competent bacteria in their natural environment.
自然转化是一种广泛存在的细菌水平基因转移（HGT）机制，通过获取促进毒力、抗生素耐药性和其他特征的基因，能够塑造它们的进化。最近的工作已经确立，通过 VI 型分泌系统、细菌素和毒性噬菌体的邻域捕食在促进 HGT 方面起着重要作用。在这里，我们证明在甲壳质河口微宇宙中，K139 溶原体会通过依赖噬菌体的邻域捕食非溶原体来增强 HGT。通过捕食非溶原体，K139 溶原体在这些微宇宙条件下也具有适应性优势。我们的工作揭示的生态策略提供了对细菌在其自然环境中适应所使用的进化机制的更好理解，并有助于我们理解可能驱动细菌基因组中噬菌体维持的选择压力。噬菌体在细菌物种中几乎无处不在。这些整合的噬菌体元件以前通过它们进行转导（广义或专门）的能力在很大程度上与水平基因转移（HGT）有关。在这里，我们表明噬菌体编码的病毒颗粒通过自然转化促进邻域捕食，从而增强 HGT。我们的发现有助于全面了解参与噬菌体维持的动态力量，这最终推动了其自然环境中自然感受态细菌的进化。
