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A characterization of the effectors of a plant pathogen

Reference	BBS/E/J/000CA452
Principal Investigator / Supervisor	Professor Saskia Hogenhout
Co-Investigators / Co-Supervisors
Institution	John Innes Centre
Department	John Innes Centre Department
Funding type	Research
Value (£)	71,123
Status	Completed
Type	Institute Project
Start date	23/05/2011
End date	22/05/2013
Duration	24 months

Abstract

Phytoplasmas are insect-transmitted pathogens of plants that cause disease in important crops. Aster Yellows phytoplasma strain Witches’ Broom (AY-WB) induces symptoms that indicate developmental processes are perturbed in infected plants, including the growth of leaf-like flowers (phyllody) and the proliferation of stems (witches’ broom phenotype). We hypothesize that AY-WB secretes effector proteins that alter plant development and down-regulate host defense mechanisms. The objectives of this proposal are: i) determine how the effector genes are regulated; and ii) functionally characterize a subset of putative effectors to determine whether these proteins modulate plant development. To realize these objectives, we propose the following experimental approaches. We will map promoters associated with genes encoding candidate effectors that are highly expressed in an insect or a plant host. Promoter sequences and upstream regions will be examined to identify regulatory elements that are associated with a host-specific expression, providing insight into the regulation of phytoplasma gene expression, and allowing the development of in silico promoter prediction methodologies. Furthermore, we will select a subset of AY-WB candidate effectors for functional characterization. The effector genes will be expressed in Arabidopsis, and the phenotype of the transgenic plants will be assessed to identify alterations in development. As phytoplasmas are restricted to the phloem of infected hosts, we will employ immunocytology to localize the effector proteins in infected plant tissues to assess whether the secreted phytoplasma proteins unload from the phloem and whether AY-WB encodes (additional) proteins that facilitate effector unloading into distal tissues. Finally, we will screen the putative effectors to probe for protein-protein interactions against an Arabidopsis cDNA library as a means of identifying (plant) host proteins that are targeted by the bacterial effectors.

Summary

unavailable

Committee	Not funded via Committee
Research Topics	Crop Science, Microbiology, Plant Science
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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