The aphid factor – investigating how aphid genetic diversity and endosymbionts impact plant virus epidemiology

Keele University

This PhD project will be jointly supervised between Keele University and Harper Adams University. This student will be based at and registered with Keele University. There will be visits to Harper Adams University based on experimental work as necessary.

Plant viruses threaten global food security and many are transmitted (vectored) by aphids. Controlling aphids can break virus transmission, reducing the impact of these diseases. Insecticide application can control aphids, however aphids are developing resistance. Plant-virus-vector interactions all influence the spread of plant viruses in the field, but we do not yet fully understand how the natural genetic variation of each ‘partner’ in this three-way interaction impacts virus spread. 

Barley yellow dwarf virus (BYDV) is an aphid vectored disease of cereal crops. BYDV can cause up to £136 million in economic losses per year in wheat, a key cereal crop in the UK. Bird cherry oat aphid (Rhopalosiphum padi) and grain aphid (Sitobion avenae) are the two primary vectors for BYDV. Beside vectoring viruses, aphids themselves also cause direct damage to the plant from their feeding activities. 

There is genetic variation within a single aphid species but because aphids reproduce asexually throughout much of the year this can lead to development of clonal populations. Aphids also harbour symbiotic bacteria (endosymbionts) which can influence their fitness and virus vectoring efficiency.

 This project aims to explore the relationship between aphid genetic diversity and bacterial endosymbiont profile, and link this with their capacity to vector plant virus.

 The main objectives of the project are:

1.    To determine the genetic diversity of aphids collected from UK wheat fields

2.    To explore if there is clone-specific aphid endosymbiont diversity

3.    To investigate the aphid clone-specific efficiency to vector BYDV

 The student will use molecular biology approaches to perform microsatellite genotyping, sequencing, PCR, and RT-PCR to identify bacterial endosymbionts and virus presence in the aphids. The student will assess aphid fitness by recording intrinsic rates of increase and mean relative growth rates of individual aphids with the use of a microbalance. The student will develop a range of skills both in the lab and in the field, in molecular biology, bioinformatics, and entomology. The student will have access to various training opportunities through the university.

The successful candidate will be joining a team of plant and mammalian virologists and entomologists who work on a range of vector-borne diseases at Keele University and Harper Adams University.

Please go to for further information, including candidate profile.

Please ensure you quote FNS_TTPBApril 23 on your application.

Candidates should hold, or expect to gain a 1st class or a good 2:1 Bachelors degree and/or an appropriate Masters qualification.

The interviews will be held in June.

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