Plant Pathogen Temperature Ecology.

Lead Research Organisation: UNIVERSITY OF EXETER
Department Name: Biosciences

Abstract

Fungal and oomycete plant pathogens threaten global food security. Crop infection risk is determined in part by temperature and moisture availability, and climate change will alter distributions of both crops and their pathogens. Mathematical models of changing pathogen distributions often implicitly assume that fungi will respond to temperature in the future much as they do now, with no evolution to changing conditions. However, a small amount of existing research has shown that fungi can acclimatize and evolve rapidly to withstand warming. This studentship will combine laboratory experiments and modelling to investigate plant pathogen temperature ecology across various biological scales.

1. What is known about variation in plant pathogen temperature responses? The student will conduct a detailed literature survey of fungal and oomycete plant pathogen temperature responses. Temperature responses will be compared across life cycle stages, and the student will test the hypothesis that in vitro and in planta temperature responses differ. The student will statistically investigate the relationships between temperature tolerance, host specificity, biogeography, and evolutionary relationships among fungi.

2. How will plant pathogen infection risk alter globally under climate change? The student will utilise published infection temperature responses for fungi and oomycetes to investigate whether increasing temperatures will shift infection risk at the global scale. For example, will warming result in increased or decreased disease risk, and if so, where?

3. Can a mechanistic modelling approach be utilised to predict Septoria tritici Blotch (STB) disease risk in space and time? The student will develop an experimentally-parametrised mechanistic model of STB and compare model predictions to observed disease risk.

4. How does Zymoseptoria tritici respond to increasing culture temperatures in the lab? The student will investigate the changes undergone by fungal cultures, assessing molecular and morphological aspects of fungal biology.

5. Is there a trade-off between temperature acclimation and virulence? Evolutionary theory predicts a trade-off between responses to different types of stress. For example, a pathogen responding to high temperature might be less able to infect the host plant. The student will test whether fungal isolates that have been acclimated to grow at higher temperatures retain virulence on wheat.

Through this doctorate the student will receive training in statistical analysis, ecological and evolutionary theory, disease risk modelling, plant pathology, microbiology and fundamental lab skills, as well has making an important contribution to the science of climate change and global food security.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M009122/1 01/10/2015 31/03/2024
1768131 Studentship BB/M009122/1 01/10/2016 28/04/2021 Thomas Chaloner
 
Description (1) Developed a weather-dependent mathematical model of Septoria tritici blotch (STB) disease in wheat. This represents an important step in integrating mechanistic information of ecological responses of pathogens in the context of diseases risk modelling and highlights area for future research and development.
(2) Developed a temperature-dependent model of altered plant pathogen infection risk at the global scale under climate change (preprint soon to be uploaded to bioRxiv). This work has important impacts on future food security, biosecurity and disease risk management.
(3) Analysed the geometry and evolution of the ecological niche in plant-associated microbes - the ecological niche determines where in space and time pathogens are able to cause disease. Hence, analysing niche geometry and evolution is of crucial importance to help mitigate future reshuffling of pathogens due to anthropogenic influence.
Exploitation Route (1) Our weather-dependent model of STB disease risk can serve as a platform for future model development, thereby improving the utility of disease risk models to inform management strategies, including - integrating host and pathogen ecological responses, downscaling of ecological parameters (i.e. finer scale temperature and canopy wetness parameters), inclusion of within- and between-season variability in pathogen responses (i.e. evolution of temperature responses). All bespoke code associated with this mechanistic model is available on GitHub.
(2) All digitised and processed temperature response data will be made available on Dryad repository, upon publication, for use by plant pathologists, epidemiologists, and microbial ecologists. This dataset has over 8000 data points from over 600 pathogens.
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Environment

 
Title Weather-dependent model of STB 
Description Bespoke model code associated with https://doi.org/10.1098/rstb.2018.0266. 
Type Of Material Computer model/algorithm 
Year Produced 2019 
Provided To Others? Yes  
Impact Model serves as a suitable and relevant starting point for combining pathogen ecophysiological models with host-centred models, potentially enabling a fully predictive model of STB burden and wheat yield impacts. 
URL https://github.com/thomaschaloner/A_new_mechanistic_model_of_weather-dependent_Septoria_tritici_blot...
 
Description Green Man Festival - Einstein's Garden 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact https://www.swbio.ac.uk/2017/08/25/blog-by-jordan-cuff-on-the-swbio-dtps-plant-power-station/
https://www.swbio.ac.uk/2018/10/16/promoting-plant-power-green-man-festival/
Year(s) Of Engagement Activity 2017,2018
URL https://www.swbio.ac.uk/2018/10/16/promoting-plant-power-green-man-festival/