Genomic surveillance may help track pathogen evolution to prevent crop failures
Study identifies genetic lineage of wheat fungus and fungus-resistant wheat gene
Pests and diseases may reduce wheat yields by over 20% globally. A study published in PLOS Biology by Sergio Latorre at University College London, London, United Kingdom and colleagues suggests that genomic surveillance may be an effective disease management tool with the ability to trace the lineage of emerging crop diseases, and to identify genetic traits for breeding disease resistant lines.
Wheat crops across the globe are threatened by wheat blast, an emerging fungal disease. However, disease-management strategies have been unsuccessful. In order to better understand emerging pathogen genotypes and lineages, researchers conducted both genome analyses and laboratory experiments. They genetically sequenced and genotyped wheat blast and tested different lines of wheat for genetic resistance to blast fungus and susceptibility to fungicide.
The researchers found that the recent emergence of wheat blast in Asia and Africa was caused by a single clonal lineage of the wheat blast fungus and that outbreaks in Zambia and Bangladesh originated independently. They also identified Rmg8, a disease resistant wheat gene. These findings highlight how genomic surveillance may help plant breeders more effectively select traits to develop disease resistant lines.
The research may provide new tools to help counteract emerging plant pathogens. However, future studies are needed to address the likelihood of crop diseases evolving resistance to pesticides and fungicides and evaluate other potential strategies that reduce reliance on chemical inputs.
According to the authors, “The emergence of variants that are more damaging than the current genotypes is probable within short timescales. This could happen either through mutations or sexual recombination with endemic blast fungus populations. Such variants could have increased virulence and fungicide tolerance thus adding to the difficulty in managing the wheat blast disease. These findings underscore the need for genomic surveillance to improve tracking and monitoring of the wheat blast fungus on a global scale and identifying variants of concern as soon as they emerge”.
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