NERC GW4+ DTP PhD studentship: Exploring the microbiome of malaria vectors

This project is one of a number that are in competition for funding from the NERC Great Western Four+ Doctoral Training Partnership (GW4+ DTP). At least 4 fully-funded studentships that encompass the breadth of earth and environmental sciences are being offered to start in September 2017 at Exeter. The studentships will provide funding for a stipend which is currently £14,296 per annum for 2016-2017, research costs and UK/EU tuition fees at Research Council UK rates for 42 months (3.5 years) for full-time students, pro rata for part-time students.

Main supervisor: Dr. Ben Raymond, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall

Project description:

Malaria is one of the most globally important infectious diseases, causing around half a million deaths annually. Substantial progress in disease prevention has been achieved by the use of indoor spraying and pesticide impregnated bednets. However, these achievements are threatened by the evolution of resistance to insecticides and the switch in importance to outdoor biting mosquitoes such as Anopheles arabiensis. New tools that can target outdoor biting vectors are therefore urgently needed.

There are various strategies, using either naturally occurring bacteria or genetically modified strains that could be used to reduce outdoor transmission Directly manipulating bacteria communities in the gut and gonads of mosquitoes can reduce transmission via insect immunity or by reducing mosquito lifespan, as only old female insects are vectors (1). The microbiome has also been a target of transgenic strategies that can block malarial lifecycle in the insect (2).

Deploying any of the above strategies would benefit from a full characterization of the bacteria associated with malaria vectors. Important issues include identifying which bacterial species can infect a range of species (An. gambiae, An. arabiensis) across a broad geographical area. Isolating and characterizing bacteria from the gonads, that are potential sexually-transmitted insect parasites, could also lead to the discovery of new bio-control tools. Understanding how the bacterial communities in Anopheles are constructed would also be important in deploying bacterial tools. While culturable microbiomes can show great diversity (Fig 1A), pilot experiments on newly emerged female An. gambiae show that we can replace 70% of the culturable gut bacteria with a marked laboratory strain (Fig 1B). Understanding the ecological factors that increase or decrease our ability to manipulate microbiomes would be a key advance.

In this PhD, the student will apply modern next generation sequencing methods (shotgun sequencing) and culture-based microbiology to explore the microbiome of the mosquito guts and gonads. This study will exploit the Natural History Museum’s extensive collections. It will also involve collection of fresh material from Tanzania and experimental work in controlled rearing facilities to characterize the community ecology of insect microbiomes.

The student will benefit from expertise in the Raymond lab (Exeter) in insect associated microbes, microbial ecology and the development of new biocontrol tools (3), and Prof Barnes (NHM) expertise in bioinformatics, next-generation sequencing and the characterization of curated biological material (4). This project also involves collaborative support from researchers in Tanzania (Dr Kija Nghabi) and at Imperial College (Dr Lauren Cator).

Please see http://www.exeter.ac.uk/studying/funding/award/?id=2314 for full details, figures mentioned and how to apply.