BIOCONT6SS · Inter-bacterial competition mediated by the type VI secretion system (T6SS): promising role in the biocontrol properties of Pseudomonas putida
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2016-09-01 → 2018-08-31
- EU contribution
- €195,455
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
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Results in brief
Inter-bacterial competition mediated by the type VI secretion system (T6SS): promising role in the biocontrol properties of Pseudomonas putida
Plant pathogens (phytopathogens) are the causal agents of many severe crop diseases including bacterial wilt, crown gall and rot. These diseases are directly responsible for the decline in the yield and the quality of the crops and cause serious economic losses in the agricultural sector. Chemical pesticides has been successfully used for years to protect crop plants but has many downsides for the environment including soil erosion and the rise of resistance to these chemical products. The H2020 program has prioritised initiatives to promote environmentally sustainable agriculture. In this context, the biological control of plant diseases by beneficial microorganisms (biocontrol) is considered a promising alternative to pesticides to protect economically-crucial plant crops. Fully understanding the biocontrol mechanisms performed by well-established agents is key to progress in this field of research. Pseudomonas putida is an important biocontrol agent, in this project, we aim to analyse the type VI secretion systems (T6SSs) to determine whether T6SSs play a role in the biocontrol properties of this strain. T6SSs are bacterial nanomachines used to inject toxic effectors into target cells. This secretion system plays an important role in inter-bacterial competition and thus it is susceptible to be an important mechanism of biocontrol used for beneficial bacteria to eradicate plant pathogens. A preliminary in silico analysis revealed the existence of three T6SSs in P. putida KT2440 (K1, K2 and K3). The project was designed to advance in the study of P. putida T6SSs by addressing the following main issues: 1) performing a phylogenetic study of the T6SSs in P. putida strains; 2) broadening and completing the in silico study; 3) identifying P. putida competitors targeted by the system; 4) characterising the identified effectors and immunity proteins and 5) determine the role of Pseudomonas-T6SS in biocontrol.
Data: CORDIS, © European Union
Project objective
Bacterial type VI secretion systems (T6SSs) are recently discovered nanomachines used to inject effectors into prokaryotic or eukaryotic cells. Therefore, T6SSs are involved in both inter-bacterial competition and bacterial pathogenesis. In this project, I propose to study the T6SS of Pseudomonas putida a soil bacterium with the capacity to colonise the root of crop plants. The colonisation by this bacterium provides growth advantages to the plant and, importantly, protection against plant-pathogens. This makes P. putida a relevant biocontrol agent. Since T6SS is mainly used by environmental bacteria for inter-bacterial competition, one might speculate that T6SSs play a relevant role in the biocontrol properties of P. putida. An in silico analysis of P. putida KT2440 genome revealed the existence of three putative T6SSs: H1, H2 and H3. I have determined that H1-T6SS is active and can be used to kill the serious phytopathogen Pseudomonas syringae. Mutants in H1-T6SS structural components lack the ability to kill model prey strains. In this project, I propose to use these mutants in competition assays with several microorganisms to further identify H1-T6SS targets, especially other resilient phytopathogens such as Agrobacterium tumefaciens and Ralstonia solanacearum. Furthermore, I will assess the role of T6SSs in the biocontrol properties of P. putida using infected plants. Moreover, I have identified novel H1-T6SSs effectors and their cognate immunity proteins (EI pairs) which belong to EI families without functionally characterised members. I will characterise the identified EI pairs at a functional, biochemical and structural biology level.In addition to the fundamental interest of the characterisation of new T6SSs, elucidation of their role in the biocontrol activity of P. putida is entirely original and has not been addressed thus far. Our findings will be highly relevant for future applications in agricultural biotechnology.
Original text from CORDIS.
Participants
- IMPERIAL COLLEGE OF SCIENCE TECHNOLOGY AND MEDICINE · LondonCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union