About the Project
BACKGROUND
Beans provide one of the most important staple sources of dietary protein in many parts of Africa and worldwide, and are an important part of the horticultural export market. However, diseases of beans caused by bacterial pathogens can result in a significant loss of yield and quality. The bacterial pathogen Pseudomonas syringae pv. phaseolicola (Psp) causes a disease of bean known as halo blight, which attacks both leaves and pods. Leaf symptoms first appear as small, water-soaked spots. These lesions rapidly become necrotic and infection of expanding leaves may result in leaf distortion. A chlorotic halo of yellow tissue can often be seen surrounding necrotic spots, which is associated with production of a toxin known as phaseolotoxin. In cases of severe infection, a generalized systemic chlorosis can occur. Symptoms also occur on pods and stems as water-soaked and necrotic lesions. Systemic infection can occur from infected seeds. However, some isolates of Psp can also cause systemic symptoms when inoculated into leaves. Different isolates of Psp vary in the degree to which they are able to cause systemic infection in host plants, with some isolates causing an aggressive systemic infection on susceptible host plants.
PROJECT AIM
The aim of this project will be to understand the molecular mechanisms involved in systemic infection by Psp, studying isolates of Psp collected in South Africa that vary in the degree to which they cause systemic infection. The project will involve the characterisation of Psp isolates using genomic and phylogenetic approaches, complemented by the use of molecular biology, microscopy and biochemical approaches to investigate the mechanisms involved in systemic infection and in resistance to systemic infection. We will also investigate whether strains that are able to cause systemic infections show a higher rate of transmission to and from seeds. The project will be undertaken in collaboration with Dr. Deidre Fourie (ARS, South Africa).
STUDENT PROFILE
The student appointed to this project will gain experience in microbiology, bioinformatics, plant science, molecular genetics, bio-imaging and biochemistry. Students should also be able to demonstrate strong mathematical or statistical skills. The project would suit a student with a relevant academic background and proven research experience in a relevant discipline.
APPLICATION DEADLINES
There are three application deadlines, but you are strongly encouraged to apply in November or January.
- Friday 16 November 2018
- Friday 25 January 2019
- Friday 1 March 2019
* Note: Applications must be submitted by 12 noon (midday) on these days.
Please ensure that you contact potential supervisors well in advance of these deadlines. Later applications may be considered if places are available.
Funding Notes
Prospective students are encouraged to apply to the Oxford Interdisciplinary Bioscience DTP. International applicants are encouraged to explore scholarship options that are available to them through the University of Oxford, their home countries or organisations such as the Commonwealth Scholarship Commission.
References
Preston G.M. (2017). Profiling the extended phenotype of plant pathogens. Molecular Plant Pathology 18, 443-456
Neale H.C., Laister R., Payne J., Preston G., Jackson R.W., Arnold D.L. (2016). A low frequency persistent reservoir of a genomic island in a pathogen population ensures island survival and improves pathogen fitness in a susceptible host. Environmental Microbiology. 18, 4144-4152.
O'Leary, B. M., Neale, H. C., Geilfus, C. -M., Jackson, R. W., Arnold, D. L., and Preston, G. M. (2016) Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae pv. phaseolicola. Plant, Cell and Environment. 39, 2172-84.
Arnold D.L., Lovell H.C., Jackson R.W., Mansfield J.W. 2011. Pseudomonas syringae pv. phaseolicola: from ‘has bean’ to supermodel. Molecular Plant Pathology 12: 617-27
Tock A.J., Fourie D., Walley P.G., et al. (2017) Genome-wide linkage and association mapping of halo blight resistance in common bean to race 6 of the globally important bacterial pathogen. Frontiers in Plant Science. 8:1170.
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