Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA.
Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.
J Bacteriol. 2021 Oct 25;203(22):e0026521. doi: 10.1128/JB.00265-21. Epub 2021 Sep 13.
Pseudomonas aeruginosa strains PA14 and PAO1 are among the two best-characterized model organisms used to study the mechanisms of biofilm formation while also representing two distinct lineages of P. aeruginosa. Previous work has shown that PA14 and PAO1 use different strategies for surface colonization; they also have different extracellular matrix composition and different propensities to disperse from biofilms back into the planktonic phase surrounding them. We expand on this work here by exploring the consequences of these different biofilm production strategies during direct competition. Using differentially labeled strains and microfluidic culture methods, we show that PAO1 can outcompete PA14 in direct competition during early colonization and subsequent biofilm growth, that they can do so in constant and perturbed environments, and that this advantage is specific to biofilm growth and requires production of the Psl polysaccharide. In contrast, P. aeruginosa PA14 is better able to invade preformed biofilms and is more inclined to remain surface-associated under starvation conditions. These data together suggest that while P. aeruginosa PAO1 and PA14 are both able to effectively colonize surfaces, they do so in different ways that are advantageous under different environmental settings. Recent studies indicate that P. aeruginosa PAO1 and PA14 use distinct strategies to initiate biofilm formation. We investigated whether their respective colonization and matrix secretion strategies impact their ability to compete under different biofilm-forming regimes. Our work shows that these different strategies do indeed impact how these strains fair in direct competition: PAO1 dominates during colonization of a naive surface, while PA14 is more effective in colonizing a preformed biofilm. These data suggest that even for very similar microbes there can be distinct strategies to successfully colonize and persist on surfaces during the biofilm life cycle.
铜绿假单胞菌菌株 PA14 和 PAO1 是两种研究生物膜形成机制的最佳模式生物，它们代表了铜绿假单胞菌的两个不同谱系。以前的工作表明，PA14 和 PAO1 利用不同的策略进行表面定殖；它们的细胞外基质组成也不同，从生物膜中分散回周围浮游相的倾向也不同。在这里，我们通过探索这些不同的生物膜产生策略在直接竞争中的后果来扩展这项工作。使用差异标记的菌株和微流控培养方法，我们表明 PAO1 可以在早期定植和随后的生物膜生长过程中与 PA14 进行直接竞争，它们可以在恒定和扰动的环境中进行竞争，并且这种优势是特定于生物膜生长的，需要产生 Psl 多糖。相比之下，铜绿假单胞菌 PA14 更能够入侵预先形成的生物膜，并且在饥饿条件下更倾向于保持与表面相关联。这些数据表明，尽管铜绿假单胞菌 PAO1 和 PA14 都能够有效地定殖表面，但它们以不同的方式在不同的环境条件下具有优势。最近的研究表明，铜绿假单胞菌 PAO1 和 PA14 采用不同的策略来启动生物膜形成。我们研究了它们各自的定植和基质分泌策略是否会影响它们在不同生物膜形成条件下的竞争能力。我们的工作表明，这些不同的策略确实会影响这些菌株在直接竞争中的表现：PAO1 在定殖新表面时占主导地位，而 PA14 在定殖预先形成的生物膜时更有效。这些数据表明，即使对于非常相似的微生物，在生物膜生命周期中成功定殖和在表面上持续存在也可能有不同的策略。
