How should aggressive plant pathogens be reported? The Sainsbury Laboratory has collaborated on a project that is tracing the spread of the virulent fungal disease wheat blast – the findings coincide with the development of a new code of ethics for reporting diseases.
Risk to food security
Wheat blast is a fast-acting and devastating fungal disease that threatens food safety and security in tropical areas in South America and South Asia. It directly strikes the wheat ear, with the result that the grain shrivels and deforms in less than a week from the first symptoms, leaving farmers no time to act.
The disease is caused by the fungus Magnaporthe oryzae pathotype Triticum. It was originally detected in Brazil in the 1985 and quickly spread across the continent. It was later detected in Bangladesh in 2016 and then two years later it struck Zambia.
It was not known if the disease was caused by the same pathogen – that had travelled between the continents – or by other strains of Magnaporthe oryzae shifting their host species.
Where did it come from?
To answer this question about its origins researchers at The Sainsbury Laboratory, collaborated with colleagues internationally to analyse samples of wheat blast from the three continents.
Molecular analyses showed that the same set of 84 genetic markers were found in the three sets of samples, suggesting that the outbreaks were caused by the same clone called B71.
Additionally all the samples in Zambia from 2018 – 2020 were the same clone indicating that there was only one introduction – this was also the case for Bangladesh.
Knowing that this pandemic clone is genetically similar to those in South America and Bangladesh means that Zambian farmers can benefit from using similar wheat blast management strategies that have proven successful over the years
By creating the website Open Wheat Blast, rapid sharing of data between the researchers was facilitated and this proved crucial for tracking wheat blast pathogens.
Sharing data helps fight disease
Dr Pawan Singh, Head of Wheat Pathology at CIMMYT said, “The information generated is very important and has significant impact in developing and implementing wheat blast management strategies.”
Wheat blast was first detected in Zambia during the 2017-18 rainy season, but only reported to neighbouring countries in 2019. Cases such as these showcase the need for a code of ethics for reporting diseases and this has been proposed by the ISPP (International Society for Plant Pathology).
The report “A pandemic clonal lineage of the wheat blast fungus” can be found here.
More information about The Sainsbury Laboratory.