Role of bacterial Csps in colonisation, plant immunity and disease control

Supervisors: Maurice Gallagher, Gary Loake and Nicola Holden

Project Description:

Plants are the major food source for humans and livestock. Yet, losses from infection are immense. Throughout evolution elaborate schemes have emerged for plant pathogen recognition and response. A fundamental system involves perception of/response to common microbial elicitors, termed pathogen/microbe associated molecular patterns (P/MAMPs). Recent advances have shown that a surface receptor, CORE, in plants such as tomato1, selectively recognise and respond with high affinity to a family of PAMPS, the cold shock proteins (Csps), by activating immune defences. Csps are ubiquitous in bacteria and we have already shown that some Csps in food-borne pathogens are induced on exposure to plant extracts2. As such, bacterial Csps hold potential as natural ‘next-generation elicitors’ of plant immunity and disease control. However, more extensive investigation of the roles of these Csps in plant colonisation; of the plant response system and; of the downstream components involved, is needed. The aim now is to further define these processes so that the feasibility of using Csps as a means for enhancing infection control in plants can be assessed.

O1. Determine the role of CSP in bacterial colonisation of plants, using csp knock-out mutants
O2. Characterise the PAMP response to Csps in tomato using csp mutants and a Csp peptide
O3. Define the defence response pathways to Csps

The plant-microbe studies will be based on human and plant pathogen colonisation and defence response assays, using models already established in the labs of the PIs (e.g. for Salmonella-tomato and Pseudomonas-Arabidopsis), and a unique set of k/o mutants for csp genes which has been generated in S. enterica sv. Typhimurium3. Key immune response markers will be identified in tomato and Arabidopsis from: (i) inoculation (leaf infiltration) with wild type pathogens/csp mutants; (ii) transcriptional, mutant and/or phenotypic assays; (iii) expression of the Csp peptide receptor ‘CORE’ and; (iv) use of purified Csps as agonists.

This cross-disciplinary project will provide expertise in microbiology and plant sciences, ranging from molecular biology to whole organism studies (Hazard Group 2 human and plant pathogens and their hosts). The student will benefit from the expertise and support across two prestigious institutions, of three laboratories with central interests in infection and disease control.

1. Saur IML, et al. (2016) Proc Natl Acad Sci USA 113:3389-3394.
2. Crozier L, et al. (2016) Front Microbiol 7.
3. Ian Wesley Hutchinson, Characterisation of the cold shock response of Salmonella enterica sv.Typhimurium-genomic and genetic analysis. Thesis ( Ph.D.) University of Edinburgh 2005.

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