Intra- and inter-specific competition and the evolution of cooperation in Bacillus thuringiensis
Lead Research Organisation:
University of Oxford
Department Name: Zoology
Abstract
Cooperation is a common feature of bacterial lifestyles. This may be particularly true of bacteria that cause diseases (pathogenic bacteria) and of beneficial bacteria that live in close association with larger hosts (symbiotic bacteria). Many of the essential tools that enable bacteria to exploit hosts are based on what can be called 'public goods'. These are enzymes or toxins and other compounds that bacteria must export outside the cell in order to break open host cells and harvest the resources. Bacteria also export chemical signals that communicate information about their abundance within hosts to other bacteria and may thereby coordinate attack. Efficient use of hosts therefore requires bacteria to act collectively, if a low proportion of bacteria fail to cooperate bacterial infections should to be less successful and produce fewer infections in new hosts. These public goods are expensive to make in terms of resources. In evolutionary terms cooperation can be unstable because bacteria may leave more offspring within hosts if they 'cheat' and fail to contribute to these expensive cooperative products. Evolutionary theory has made predictions about how cooperation could be maintained. If most infections are established by close relatives with similar strategies, metabolically expensive cooperation will benefit their relative and they, in turn will then spread the genes for cooperation. In addition, while competition within hosts can lead to selection for cheating, competition between groups of bacteria inhabiting different hosts will select for groups that exploit their host more efficiently, and which therefore cooperate. The evolutionary forces that can maintain cooperation between hosts and symbiotic bacteria are diverse. However, one possible mechanism is that host can discriminate between bacteria that are exploitative or not and produce increased immune responses against symbionts that are not cooperative. I propose to test these evolutionary ideas on cooperation, in relation to the production of toxins, antibiotics and chemical signals. Prelimary data also indicate that the exploitation of hosts by Bt is strongly affect by competition with symbionts such as P. agglomerans. I will test how competition with symbionts affects the expression of cooperative toxins. Conversely, these symbionts can cooperate with Bt rather than continue to cooperate with hosts as gut symbionts. I will test how host insects react to infections with 'cheating' symbionts. I will use a study system which is familiar to me and also of environmental and medical importance. This system is the insect-killing bacteria Baccillus thuringiensis, a caterpillar host (the larvae of the diamondback moth) and the gut symbiont Pantoea agglomerans. B. thuringiensis (Bt) is used as a biological pesticide. It is applied against pests in horticulture, forestry and fruit productionan and against mosquito larvae. It has an excellent safety record, it does not harm humans, animals or beneficial insect predators and is licensed as an organic spray. While Bt pesticides are efficient at killing pests they are relatively poor at being transmitted as a disease from pest to pest after spraying. Improved transmission would have many benefits for the ability of Bt to control pests. Preliminary data in my laboratory suggests that cooperative traits are vital for efficient transmission between hosts, as the above theory predicts. An understanding of how cooperation maintains efficient transmission and transmission maintains cooperation could therefore be vital to understanding how to improve its use. Bt is closely related to the bacteria that causes anthrax, Bacillus anthracis and to Bacillus cereus, several strains of which cause food-poisoning in humans. These human pathogens use very similar biochemical machinery to Bt and a understanding of how these bacteria cooperate to exploit hosts may eventually be of medical significance.
People |
ORCID iD |
Benjamin Raymond (Principal Investigator) |
Publications
Bonsall MB
(2008)
Lethal pathogens, non-lethal synergists and the evolutionary ecology of resistance.
in Journal of theoretical biology
Cornforth DM
(2015)
Bacterial Cooperation Causes Systematic Errors in Pathogen Risk Assessment due to the Failure of the Independent Action Hypothesis.
in PLoS pathogens
Ferry, N.; Gatehouse, A.M.R.
(2009)
Environmental Impact of Genetically Modified Crops
Matthews A
(2019)
Rhizobacterial Community Assembly Patterns Vary Between Crop Species.
in Frontiers in microbiology
Matthews AC
(2019)
Shifts along the parasite-mutualist continuum are opposed by fundamental trade-offs.
in Proceedings. Biological sciences
Medaney F
(2016)
Ecological and genetic determinants of plasmid distribution in Escherichia coli.
in Environmental microbiology
Méric G
(2018)
Lineage-specific plasmid acquisition and the evolution of specialized pathogens in Bacillus thuringiensis and the Bacillus cereus group.
in Molecular ecology
Raymond B
(2008)
Ecological consequences of ingestion of Bacillus cereus on Bacillus thuringiensis infections and on the gut flora of a lepidopteran host.
in Journal of invertebrate pathology
Raymond B
(2010)
Environmental factors determining the epidemiology and population genetic structure of the Bacillus cereus group in the field.
in PLoS pathogens
Raymond B
(2008)
Quantifying the reproduction of Bacillus thuringiensis HD1 in cadavers and live larvae of Plutella xylostella.
in Journal of invertebrate pathology
Raymond B
(2018)
An appeal for a more evidence based approach to biopesticide safety in the EU.
in FEMS microbiology ecology
Raymond B
(2017)
In defense of Bacillus thuringiensis, the safest and most successful microbial insecticide available to humanity - a response to EFSA.
in FEMS microbiology ecology
Raymond B
(2022)
Passage and the evolution of virulence in invertebrate pathogens: Fundamental and applied perspectives.
in Journal of invertebrate pathology
Van Leeuwen E
(2015)
Making pathogens sociable: the [corrected] emergence of high relatedness through limited host invasibility.
in The ISME journal
Zhou L
(2018)
Combining the high-dose/refuge strategy and self-limiting transgenic insects in resistance management-A test in experimental mesocosms.
in Evolutionary applications
Description | see entry to NE/E012671/2 NE/E012671/1 simply refers to the first two years of this fellowship at Oxford. |
Exploitation Route | see entry to NE/E012671/2 NE/E012671/1 simply refers to the first two years of this fellowship at Oxford. |
Sectors | Agriculture Food and Drink Creative Economy Healthcare Pharmaceuticals and Medical Biotechnology |
Description | AHDB studentship scheme |
Amount | £71,400 (GBP) |
Organisation | Agricultural and Horticulture Development Board |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 09/2018 |
End | 09/2021 |
Description | Group selection as a novel tool to screen and improve biological pesticides |
Amount | £371,386 (GBP) |
Funding ID | BB/S002928/1 |
Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
Sector | Public |
Country | United Kingdom |
Start | 12/2018 |
End | 11/2022 |
Description | Industrial Partnership - (as part of BBSRC IPA award) |
Organisation | Dow AgroSiences |
Country | United Kingdom |
Sector | Private |
PI Contribution | My team will be engaged in producing mutants with increased virulence to resistant insect pests, as well as screening strain collections and toxin libraries for novel or improved isolates and proteins. |
Collaborator Contribution | The partner will be providing access to a sequenced strain collection as welll as to additional sequencing / molecular characaterization services. |
Impact | not yet....project began end of Feb 2019 |
Start Year | 2019 |
Description | Wuhan plasmid project |
Organisation | Huazhong Agricultural University |
Department | State Key Laboratory of Agricultural Microbiology |
Country | China |
Sector | Academic/University |
PI Contribution | Shaped research questions, wrote paper, shaped and informed analysis |
Collaborator Contribution | Collected genomic data, analysed data, co-wrote paper |
Impact | This has resulted in a publication in mBio (Zheng et al)- and is a collaboration between molecular biologists and myself as an evolutionary ecologists. Other projects related to this collaboration are still ongoing. |
Start Year | 2016 |
Title | BIOPESTICIDES |
Description | The present invention relates to Bacillus thuringiensis strains which are phenotypically stable and have increased virulence compared to the wild-type strains, whereby the increased virulence has been achieved by the exposure of the strain to a mutagen during one or more passages. Such strains are particularly useful as biopesticides. Methods for increasing virulence in microbial pesticides are also described. |
IP Reference | WO2019030529 |
Protection | Patent application published |
Year Protection Granted | 2019 |
Licensed | No |
Impact | This application has helped us in negotiations with commercial companies including Dow Agroscience and Bayer. |
Description | IBMA Copa-Cogeca workshop |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | Safety and regulation of Bt based biopesticides were discussed with stakeholders and presented to representatives of EU commission |
Year(s) Of Engagement Activity | 2017 |
URL | http://www.ibma-global.org/en/news/ibma-and-copa-cogeca-workshop-to-explore-the-implications-of-baci... |
Description | IBMA industry conference |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | This is the international biocontrol manufacturers annual meeting and very much an industry meeting rather than an academic conference. I was invited to give a talk on the safety on micro-organisms in biocontrol |
Year(s) Of Engagement Activity | 2017 |
URL | http://www.abim.ch |
Description | Open days |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Undergraduate students |
Results and Impact | The Penryn campus runs a series of open days throughtout the year designed to engage with prospective students and their families. This gives us a venue in which to talk about our research generally and that of the campus. In an event last summer, for instance, I discussed the recent invasion of diamond back moth and met with a local cabbage farmer and talked about pest control issues associated with this species. |
Year(s) Of Engagement Activity | 2016,2017,2018 |
Description | invited research application - Bayer |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | My research group was invited to pitch for research funding from Bayer in order to pursue research avenues following on from work on evoltuion of virulence in microbial insecticides. This involved preliminary meetings, a Skype presentation to the company and the submission of a research proposal. This proposal is still under consideration, and was submitted late last year. |
Year(s) Of Engagement Activity | 2018 |