Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2019

The global movement of fungal crop pathogens: models, predictions and perils. (#86)

Sarah Gurr 1 , Helen Fones 1 , Tom Chaloner 1 , Dan Bebber 1
  1. Biosciences, University of Exeter, London, UK

Over the past centuries crop diseases have led to the starvation of the people, the ruination of economies and the downfall of governments. Of the various challenges, the threat to plants of fungal (and oomycete) infection outstrips that posed by bacterial and viral diseases combined. Indeed, fungal and oomycete diseases have been increasing in severity and scale since the mid 20th Century and now pose a serious threat to global food security and ecosystem health (Fisher et al., 2012 Nature 484 185; Fisher et al., 2016 Philosophical Transactions Royal Society B 1709 201; Fones et al., 2017 Microbiology Spectrum 5 2 ).        

We face a future blighted by known adversaries, by new variants of old foes and by new diseases. Modern agricultural intensification practices have heightened the challenge - the planting of vast swathes of genetically uniform crops, guarded by one or two inbred resistance (R) genes, and use of single target site antifungals has hastened emergence of new virulent and fungicide-resistant strains. Climate change compounds the saga as we see altered disease demographics - pathogens are moving poleward in a warming world (Bebber et al., 2013 Nature Climate Change 3 11).

This presentation will highlight some current notable and persistent fungal diseases. It will consider the evolutionary drivers which underpin emergence of new diseases and manmade “accelerators” of spread. I will set these points in the context of a series of different disease modelling meta-analyses, which show the global distributions of crop pathogens (Bebber et al., 2013 Nature Climate Change 3 11), their predicted movement (Bebber et al., 2014 New Phytologist 202 901; Bebber and Gurr 2015, Fungal Genetics and Biology 74 62; Bebber et al., (2019) Global Change Biology (in press) and crop disease saturation (Bebber et al., 2014 Global Ecology and BioGeography 23 1398). I shall present a new mechanistic model for predicting Septoria Tritici Blotch disease risk on wheat grown in temperate climes (Fones and Gurr, 2015 Fungal Genetics and Biology, 79 3), parametrised with experimentally-derived data for temperature and wetness-dependent germination, growth and death in Zymoseptoria tritici (Chaloner et al., 2019 Philosophical Transactions Royal Society B rstb.2018.0266). I shall conclude with some thoughts on future threats and challenges, on fungal disease mitigation (and of the jeopardy of azole resistance (Fisher et al., 2018 Science 360 739)) and of ways of enhancing global food security.