Pseudomonas aeruginosa Uses c-di-GMP Phosphodiesterases RmcA and MorA To Regulate Biofilm Maintenance.
Pseudomonas aeruginosa Uses c-di-GMP Phosphodiesterases RmcA and MorA To Regulate Biofilm Maintenance.
复制标题
铜绿假单胞菌使用C-DI-GMP磷酸二酯酶RMCA和MORA来调节生物膜维持。
DOI：
10.1128/mbio.03384-20
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发表时间：
2021-02-02
期刊：
影响因子：
6.4
通讯作者：
O'Toole GA
中科院分区：
文献类型：
--
作者：
Katharios-Lanwermeyer S;Whitfield GB;Howell PL;O'Toole GA
我们对c-di-GMP信号传导的理解的最新进展为生物膜的调节提供了关键的见解。尽管对生物膜最初如何形成的理解有所提高，但促进这些多细胞群落长期维持的过程仍然不透明。虽然生物膜形成的早期阶段已经得到很好的表征，但对铜绿假单胞菌维持成熟生物膜的要求知之甚少。我们利用铜绿假单胞菌-噬菌体相互作用来鉴定rmcA和莫拉A，这两个基因编码双-（3′，5 ′）-环二聚GMP（c-di-GMP）降解磷酸二酯酶（PDE），并且对于生物膜维持的调节是重要的。这些基因的缺失最初导致升高的生物膜表型，其特征在于c-di-GMP、Pel多糖和/或生物膜生物量的产生增加。与野生型菌株相反，这些突变体在暴露于碳限制条件下时不能维持生物膜。这些突变体对营养限制的敏感性以及随后生物膜活力的丧失，在表型上用严格响应突变体（ΔrelA ΔspoT）再现，表明ΔrmcA和Δ莫拉突变体可能不能适当地响应营养限制。遗传和生物化学数据表明，RmcA和莫拉与Pel生物合成机制发生物理相互作用，支持一种模型，即在营养限制下，不受调节的Pel生物合成导致已建立的生物膜中ΔrmcA和Δ莫拉突变株的死亡。这些发现提供了证据表明，铜绿假单胞菌的成熟生物膜需要c-di-GMP介导的调节，以有效地响应不断变化的营养物质的可用性。此外，参与生物膜维持的PDE与建立生物膜所需的PDE不同，表明生物体如铜绿假单胞菌中的多种c-di-GMP代谢酶允许对生物膜的形成、维持或分散进行离散控制。
Recent advances in our understanding of c-di-GMP signaling have provided key insights into the regulation of biofilms. Despite an improved understanding of how biofilms initially form, the processes that facilitate the long-term maintenance of these multicellular communities remain opaque. While the early stages of biofilm formation have been well characterized, less is known about the requirements for Pseudomonas aeruginosa to maintain a mature biofilm. We utilized a P. aeruginosa-phage interaction to identify rmcA and morA, two genes which encode bis-(3′,5′)-cyclic dimeric GMP (c-di-GMP)-degrading phosphodiesterases (PDEs) and are important for the regulation of biofilm maintenance. Deletion of these genes initially results in an elevated biofilm phenotype characterized by increased production of c-di-GMP, Pel polysaccharide, and/or biofilm biomass. In contrast to the wild-type strain, these mutants were unable to maintain the biofilm when exposed to carbon-limited conditions. The susceptibility to nutrient limitation, as well as subsequent loss of biofilm viability of these mutants, was phenotypically reproduced with a stringent response mutant (ΔrelA ΔspoT), indicating that the ΔrmcA and ΔmorA mutants may be unable to appropriately respond to nutrient limitation. Genetic and biochemical data indicate that RmcA and MorA physically interact with the Pel biosynthesis machinery, supporting a model whereby unregulated Pel biosynthesis contributes to the death of the ΔrmcA and ΔmorA mutant strains in an established biofilm under nutrient limitation. These findings provide evidence that c-di-GMP-mediated regulation is required for mature biofilms of P. aeruginosa to effectively respond to changing availability of nutrients. Furthermore, the PDEs involved in biofilm maintenance are distinct from those required for establishing a biofilm, suggesting that a wide variety of c-di-GMP metabolizing enzymes in organisms such as P. aeruginosa allows for discrete control over the formation, maintenance or dispersion of biofilms.