Type VI secretion in Pseudomonas species: bacterial competition and biocontrol

假单胞菌属的 VI 型分泌：细菌竞争和生物防治

• 批准号: BB/N002539/1
• 负责人: Alain Filloux
• 金额: $ 55.44万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FN002539%2F1
• 关键词: Type; VI; secretion; Pseudomonas; species

Pseudomonas aeruginosa is a gram-negative bacterium that thrives in a multitude of environmental niches, e.g. soil, moist surfaces or plants. It has the ability to become a successful pathogen and infects a wide range of hosts, e.g. amoeba, worms, insects, plants or animals. It is also a dreadful human pathogen and is known for incurable infections in the lungs of cystic fibrosis patients. Because of this versatility of environments and hosts, P. aeruginosa encounters numerous microorganisms colonizing the same niche and competing for the same resources. It was found that a molecular weapon, called the type VI secretion system (T6SS), plays an important part in the resulting bacterial warfare.The T6SS is akin a bacteriophage tail, but instead of injecting DNA in prey cells, it injects bacterial toxins. These toxins degrade essential bacterial components, such as the cell wall/envelope or DNA, which results in irreversible damages and cell death. P. aeruginosa has been instrumental in T6SS research and numbers of breakthroughs in the field were made upon studying this organism. The development of T6SS-dependent killing assay showed that the P. aeruginosa T6SS is potent and kills most gram-negative preys. The killing assay allows the monitoring of surviving prey cells in a drop of co-culture deposited on an agar plate. The T6SS attack by P. aeruginosa is not systematic and often occurs when the encountered organism is threatening, for example by exhibiting a T6SS armory, which engages the duel.The number of T6SS toxins is far more comprehensive than anticipated. Many T6SS toxins have function that could not even be predicted. Yet the injection of these molecules in target bacteria results in death, suggesting that new antibacterial activities are to be found. We begun to unfold the T6SS toxin repertoire in P. aeruginosa and discovered that other Pseudomonas species have an active T6SS and a unique T6SS toxins repertoire. This is the case for Pseudomonas syringae, a plant pathogen, or Pseudomonas putida, a plant beneficial organism. All three Pseudomonas outcompete Escherichia coli in the in vitro killing assay, while P. aeruginosa outcompetes both P. putida and P. syringae. We showed that even though P. aeruginosa outcompetes the plant pathogen Agrobacterium tumefaciens in vitro, upon co-inoculation in planta the power relations in between these organisms is changed and A. tumefaciens prevails. These studies revealed a complex inter-bacterial relationship, in which the T6SS is central but is influenced by the specificity of interactions between organisms and the conditions and environments in which they met.In our project we investigate how the T6SS influences evolution of bacterial population and composition of polymicrobial communities. We want to build on our expertise and pioneering work in the identification of new T6SS toxins such as the DNase Tde, the characterization of T6SSs in Pseudomonas species and the use of in planta competition assays between T6SS-proficient organisms. We want to monitor the evolution of mixed bacterial populations in a dynamic environment, such as mixed biofilms using flow cells and fluorescent-tagged organisms. Biofilm is a natural lifestyle of complex bacterial populations. Each bacterial strain carries a distinct T6SS repertoire thus giving access to the role/importance of individual T6SS feature in the outcome of biofilm composition.In conclusion, we will investigate the role of the T6SS in distinct Pseudomonas species using various environmental set-ups, i.e. in vitro, mixed biofilms and in planta assays. The knowledge acquired should result in the characterization of novel antibacterial activities, understanding in the evolution of bacterial population and engineering of plant beneficial P. putida strains for the control of crops diseases. This study will have implications in areas including, Ecology and Agriculture (root colonization), Medicine (antibacterial) and Basic Sciences.

铜绿假单胞菌是一种革兰氏阴性细菌，在许多环境小生境中茁壮成长，例如土壤，潮湿表面或植物。它有能力成为一种成功的病原体并感染广泛的宿主，例如阿米巴、蠕虫、昆虫、植物或动物。它也是一种可怕的人类病原体，并且以囊性纤维化患者肺部的不可治愈的感染而闻名。由于环境和宿主的多样性，铜绿假单胞菌遇到了许多微生物在同一生态位上定居并竞争相同的资源。研究人员发现，一种名为VI型分泌系统（T6SS）的分子武器在细菌战争中起着重要作用。T6SS类似于噬菌体的尾巴，但它不是将DNA注入猎物细胞，而是注入细菌毒素。这些毒素降解细菌的基本成分，如细胞壁/包膜或DNA，导致不可逆的损伤和细胞死亡。铜绿假单胞菌在T6SS研究中发挥了重要作用，并且在研究该生物体时在该领域取得了许多突破。T6SS依赖性杀伤试验的发展表明，铜绿假单胞菌T6SS是有效的，并杀死大多数革兰氏阴性猎物。杀伤测定允许监测沉积在琼脂板上的一滴共培养物中存活的猎物细胞。铜绿假单胞菌对T6SS的攻击不是系统性的，通常发生在遇到威胁的微生物时，例如通过展示T6SS武器库，这参与了决斗。T6SS毒素的数量比预期的要多得多。许多T6SS毒素具有甚至无法预测的功能。然而，这些分子在靶细菌中的注射导致死亡，这表明新的抗菌活性有待发现。我们开始在铜绿假单胞菌中展开T6SS毒素库，并发现其他假单胞菌物种具有活性T6SS和独特的T6SS毒素库。这是植物病原体假单胞菌或植物有益生物体恶臭假单胞菌的情况。所有三种假单胞菌在体外杀伤试验中均胜过大肠杆菌，而铜绿假单胞菌则胜过恶臭假单胞菌和铜绿假单胞菌。我们发现，尽管铜绿假单胞菌在体外竞争胜过植物病原体根癌农杆菌，但在植物中共接种后，这些生物体之间的力量关系发生了变化，并且A.根瘤菌占优势。这些研究揭示了细菌间复杂的关系，其中T6 SS是核心，但受到生物体之间相互作用的特异性以及它们所遇到的条件和环境的影响。在我们的项目中，我们研究了T6 SS如何影响细菌种群的进化和组成。多微生物群落。我们希望在鉴定新的T6SS毒素（如DNase Tde）、表征假单胞菌属中的T6SS以及在T6SS熟练生物体之间使用植物竞争测定方面建立我们的专业知识和开创性工作。我们希望在动态环境中监测混合细菌种群的进化，例如使用流动池和荧光标记的生物体的混合生物膜。生物膜是复杂细菌群体的自然生活方式。每个细菌菌株携带一个独特的T6SS剧目，从而获得的作用/重要性的个人T6SS功能的生物膜composition.In结论的结果，我们将调查不同的假单胞菌属物种使用各种环境设置的作用，即在体外，混合生物膜和在植物测定。所获得的知识将导致新的抗菌活性的表征，理解细菌种群的进化和植物有益的恶臭假单胞菌菌株的工程化以控制作物疾病。这项研究将在生态学和农业（根定植），医学（抗菌）和基础科学等领域产生影响。

项目成果

Transcriptional organization and regulation of the Pseudomonas putida K1 type VI secretion system gene cluster.

转录组织和假单胞菌putida K1型分泌系统基因簇的调节。

• DOI: 10.1099/mic.0.001295
• 发表时间: 2023-01
• 期刊: MICROBIOLOGY-SGM
• 影响因子: 2.8
• 作者: Bernal, Patricia;Civantos, Cristina;Pacheco-Sanchez, Daniel;Quesada, Jose M.;Filloux, Alain;Llamas, Maria A.
• 通讯作者: Llamas, Maria A.

Causalities of war: The connection between type VI secretion system and microbiota.

• DOI: 10.1111/cmi.13153
• 发表时间: 2020-03
• 期刊: Cellular microbiology
• 影响因子: 3.4
• 作者: Allsopp LP;Bernal P;Nolan LM;Filloux A
• 通讯作者: Filloux A

RpoN/Sfa2-dependent activation of the Pseudomonas aeruginosa H2-T6SS and its cognate arsenal of antibacterial toxins.

• DOI: 10.1093/nar/gkab1254
• 发表时间: 2022-01-11
• 期刊: Nucleic acids research
• 影响因子: 14.9
• 作者: Allsopp LP;Collins ACZ;Hawkins E;Wood TE;Filloux A
• 通讯作者: Filloux A

A novel stabilization mechanism for the type VI secretion system sheath.

• DOI: 10.1073/pnas.2008500118
• 发表时间: 2021-02-16
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Bernal P;Furniss RCD;Fecht S;Leung RCY;Spiga L;Mavridou DAI;Filloux A
• 通讯作者: Filloux A

Type VI secretion systems in plant-associated bacteria.

• DOI: 10.1111/1462-2920.13956
• 发表时间: 2018-01
• 期刊: Environmental microbiology
• 影响因子: 5.1
• 作者: Bernal P;Llamas MA;Filloux A
• 通讯作者: Filloux A