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  , Dr Christopher Bell, Dr Catherine Lilley  Applications accepted all year round  Self-Funded PhD Students Only

About the Project

Introduction

The Plant Nematology Laboratory is an internationally recognised group working to understand the interactions between parasitic nematodes and their plant hosts. 

Plant pathogens cause billions of dollars of crop losses to agriculture throughout the world. Many pathogens have complex interactions with the host that allows successful pathogenesis to occur. Some plant parasitic round worms, nematodes, are good examples of organisms that have evolved complex interactions with a host plant that allows them to detect a suitable host plant, invade and establish a feeding site that will sustain the nematode for the rest of its life. Like all parasites nematodes feed from their host in order to survive and reproduce. Plant parasitic nematodes cannot survive without their host. The parasitic nematode feed from the plant for several weeks while the nematode intermittently withdraws cytoplasmic contents from the feeding site in a non-destructive manner. 

A summary of our research interests can be found at https://www.fbs.leeds.ac.uk/nem/research.htm

Overview of the nematology group

The research activity of the group spans laboratory to field studies, and ranges from improving fundamental knowledge of plant nematology to using information gained, particularly from RCUK grants, to develop new agriculturally beneficial technologies. The crop focus of the research in the U.K is potatoes, extending to rice, banana and cotton in India, Africa and China. The group has received research funding from companies in the UK, and worldwide. Work originating in the laboratory has led to numerous granted patents and the impact of the research has influenced government policy, and received attention on television, radio and in the national press.

Project available to funded applicants

The potato cyst nematodes, which can only infect Solanaceous plants, exhibit remarkable persistence and can survive dormant in the soil for decades before emerging to infect crops. Encysted eggs retained in the hardened body wall of the female are the survival stage that is able to persist in the absence of a host plant and survive adverse soil temperature and moisture. This ability to survive long periods in the soil underlies their status as agriculturally important global pathogens.

We have recently identified UK populations of potato cyst nematode that vary in their longevity in the field i.e. their viability in the absence of a potato crop declines at different rates. Importantly, we have also found that the rate at which nematode viability declines in the soil can be very much slower than previously described. This finding has important implications for management and control of potato cyst nematode, especially given the dwindling chemical control options available to UK growers. The specific molecular and biochemical mechanisms that allow this extraordinary longevity remain unanswered. These newly-identified long-lived populations offer a unique opportunity to understand the basic processes that protect the animal across a wide range of extreme environmental conditions.

Cumulative damage to biological macromolecules including DNA, RNA, proteins and lipids occurs in cells during prolonged periods of dormancy. There is thus strong selection pressure to ensure that extending lifespan in dormancy does not compromise subsequent vigour. We hypothesise that, similar to desiccation-tolerant seeds, cyst nematodes have evolved powerful protection and repair mechanisms. Recent advances by co-I West have revealed crucial roles for genome maintenance pathways in the extended survival of seeds in the quiescent state. These features are shared widely amongst anhydrobiotic organisms and provide an exciting new target for understanding and attenuating the nematode lifecycle.

This project will combine a range of techniques to reveal how nematodes have adapted to survive for extended periods in the soil. We will assess how much and what types of cellular damage accumulate during nematode dormancy. We have collections of stored nematode cysts that span a 30 year period of dormancy so we can analyse these to determine if cellular damage increases over time and when it reaches a critical point that affects survival. We will also determine the activity of DNA repair mechanisms that act in genome maintenance pathways after potato cyst nematode eggs rehydrate and are released from dormancy. We predict that cyst nematodes will require mechanisms to provide enhanced protection from damage during and after dormancy. We will analyse and compare global gene expression in dormant, rehydrated and hatched nematodes to identify the predominant stresses associated with these states and the mitigation strategies that protect and repair any damage. Finally, we will use our main findings to correlate the unexpected extreme longevity of recently discovered populations of potato cyst nematode with activity of molecular protect and repair mechanisms. This will provide the first evidence for the molecular basis of nematode longevity in the soil, fundamental to the development of a new suite of control measures.

Eligibility

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline.

Applicants whose first language is not English must provide evidence that their English language is sufficient to meet the specific demands of their study. The Faculty of Biological Sciences minimum requirements in IELTS and TOEFL tests are:

  • British Council IELTS - score of 6.0 overall, with no element less than 5.5
  • TOEFL iBT - overall score of 87 with the listening and reading element no less than 20, writing element no less than 21 and the speaking element no less than 22. 

How to apply

To apply for this project applicants should complete an online application form and attach the following documentation to support their application. 

  • a full academic CV
  • degree certificate and transcripts of marks
  • Evidence that you meet the University's minimum English language requirements (if applicable)
  • Evidence of funding

To help us identify that you are applying for this project please ensure you provide the following information on your application form;

  • Select PhD in Biological Sciences as your programme of study
  • Give the full project title and name the supervisors listed in this advert

For information about the application process please contact the Faculty Admissions Team:

e:

Biological Sciences (4)

Funding Notes

This project is open to applicants who have the funding to support their own studies or who have a sponsor who will cover these costs.

How good is research at University of Leeds in Biological Sciences?


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