Molecular mechanisms of infection of wheat by Zymoseptoria tritici

Lead Research Organisation: University of Exeter
Department Name: Biosciences

Abstract

Mycosphaerella graminicola, the causal agent of wheat Septoria tritici blotch, causes up 40% yield loss. It is the most
devastating wheat pathogen in Western Europe (Kema et al. 2002, Genetics 161:1497), with economic losses of at least
$400 million dollars (Ponomarenko et al. 2011, Plant Health Instructor.DOI:10.1094). M. graminicola invades and colonises
its host plants by hyphal tip growth. In response to infection, the plant innate defence system recognize pathogens and
trigger a complex set of physiological responses (Dodds & Rathjen 2010, Nat Rev Genet 11:539; Jones & Dangl, Nature
444:323). It is vital for fungal pathogens to overcome this host immunity very early in the infection process. An important
step in the fungal protection is the secretion of a battery of effector proteins Kale & Tyler 2011, Cell Microbiol 13:1839;
Rafiqi et al., 2012, Curr Opin Plant Biol 15:477), which suppress plant immunity, thereby allowing rapid fungal colonization
of the host. Our most recent research in the plant pathogen Ustilago maydis has shown that expression and secretion of all
three effector genes and proteins, respectively, depends on long-range early endosome-based signalling (Bielska et al.
2014, Nat. Commun., 5:5097). This pathway is novel and entirely unknown in fungal host-pathogen interaction.
This project aims to analyse a role of early endosomes in effector secretion in M. graminicola. We have already visualise
early endosome motility in this fungus. In this project, a student will (i) determine the molecular machinery behind this
motility, (ii) interfere with this machinery to block early endosome motility, and (iii) investigate the effect of this on virulence
and effector secretion during early plant infection. The student will clone three effector genes and express them in motor
mutants. The secretion of these effectors will be monitored using confocal microscopy and effector transcription will be
measured using real-time PCR. From a technical/educational point, the project includes (i) molecular cloning, (ii) live cell
imaging (confocal, laser-based epi-fluorescence), (iii) plant pathogenicity assays, and (iv) real-time PCR. This will be
complemented by a 16 week rotation project in the lab of Prof. Sarah Gurr. Here, the student will apply a mathematical
modelling approach, interrogating FERA databases, to analyse wheat blotch outbreaks and predict the movement of M.
graminicola in the European Union. A similar approach was previously published by Prof. Gurr (Bebber et al. 2014, Global
Ecol. Biogeogr., DOI: 10.1111). This theoretical project perfectly complements the lab work of the prospective student.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M009122/1 01/10/2015 30/09/2023
1622219 Studentship BB/M009122/1 01/10/2015 30/09/2019 Meike Latz