Global strain of emerging wheat disease fungus identified by genomic surveillance

Genomic surveillance could aid in tracking pathogen evolution and crop resistance, preventing crop failures, suggests a new study co-led by UCL researchers.

The new PLOS Biology paper, conducted by an international team of researchers from four continents, suggests that surveillance could help manage emerging crop diseases and identify genetic traits for breeding disease-resistant crops.

The findings highlight the threat that pests and diseases pose to global wheat yields, which could be reduced by over 20%.

One of the emerging diseases that poses a threat to wheat crops worldwide is wheat blast, a fungal disease that is now present in three continents. To better understand the disease, its origins, and its genetic makeup, researchers combined genome analyses and laboratory experiments, by which they determined the susceptibility of wheat varieties to the wheat blast fungus, and of wheat blast fungus to fungicides.

Co-lead author Dr Sergio Latorre (UCL Genetics, Evolution & Environment) said: ″Thanks to the prompt and public release of genomic data by the international scientific community through the OpenWheatBlast initiative, we were able to detect, track, and characterise the fungal lineage responsible for recent wheat blast outbreaks.″

The researchers discovered that the recent emergence of wheat blast in Asia and Africa was caused by a single clonal lineage of the fungus, with outbreaks in Zambia and Bangladesh originating independently. They also found that varieties of wheat carrying the Rmg8 gene were resistant to the fungal infection and that the fungus was sensitive to the fungicide strobilurin.

Co-author Dr Hernán A. Burbano (UCL Genetics, Evolution & Environment) said: ″The joint use of genomic surveillance and functional testing through laboratory experiments permit the establishment of genomics-informed integrated pest management practices and can guide plant breeders in the development of disease-resistant crops.″

While the research offers new tools to counteract emerging plant pathogens, the authors caution that a combined strategy that reduces reliance on chemical inputs and addresses the likelihood of crop diseases evolving resistance to pesticides and fungicides is needed.

According to the researchers, the emergence of more damaging variants of wheat blast is likely, which could increase the difficulty of managing the disease. Therefore, they stress the need for genomic surveillance on a global scale to track and monitor the wheat blast fungus and identify variants of concern as soon as they emerge.

Co-author Professor Sophien Kamoun (The Sainsbury Laboratory, University of East Anglia) added: ″This project builds on the paradigm—best illustrated by the COVID-19 pandemic—that genomic surveillance adds a unique dimension to the coordinated response to infectious disease outbreaks. We need to remain vigilant and continue genomics surveillance of wheat blast in Africa and Asia to identify Variants of Concern (VOCs) as soon as they emerge.″