Preprint reviews by Sophien Kamoun

Wheat blast disease caused by Pyricularia graminis-tritici sp. nov.

V. L. Castroagudin, S .i. Moreira , D. A. S. Pereira , S. S. Moreira , P. C. Brunner , J. L. N. Maciel , P. W. Crous , Bruce Mcdonald , E. Alves and Paulo Ceresini

Review posted on 01st May 2016

It's great that the authors have posted this article. It's obviously very timely given the current outbreak in Bangladesh and the Open Wheat Blast initiative.

These are my thoughts after a first read of the paper.

I’m not sure about naming a plant pathogen species after a specific host plant when the pathogen has additional hosts or is known to have experienced host jumps in its recent evolutionary history. There is an unfortunate tendency to do this in plant pathology.

A more neutral name, say Pyricularia infestans (or whatever), is less likely to convey the impression that these strains can only infect wheat. What if in the future this taxon causes an epidemic on oats? The same confusion that reigns today about rice vs wheat blast would apply with such a host-specific name. What about proper quarantine of other host plants that may carry this pathogen outside Brazil and now Bangladesh? Would the authorities be more likely to ignore other potential hosts when the pathogen has such a defined name?

I agree that a distinct name is needed for the wheat blast strains to clearly convey the message to the community and the authorities that this pathogen is distinct from the rice blast strain. There is no question that this has important implications for quarantine and disease management. But here two names are proposed. It is important to ensure that it is justified to divide the wheat isolates into two taxa. In the recently posted report by Croll and McDonald (Github 2016, attached), all wheat isolates are clustered in one well supported clade unlike Figure 1 of Castroagudin et al. Will the two taxa proposed here for the wheat blast isolates remain valid when genome-wide analyses are performed? Could the less-defined position of the “PoT” strains in Castroagudin et al. reflect genetic exchange between the main clusters of blast fungi?

Unfortunately, Linnaean binoms are outdated. They’re becoming more and more useless and inappropriate. It’s great that the fungal community has moved to the one species-one name concept but there is still work to do. For one thing, the current scheme fails to provide stability - a key, some would say the main reason we name things. See the twitter exchange linked below for a discussion on the topic. Perhaps, virologists have figured out a solution?

It would be unfortunate if the blast community gets bogged down in this naming issue despite what seems like a consensus that the wheat blast fungus is a distinct OTU. There are clearly more important topics to discuss and debate in relation to this invasive disease.

Croll and McDonald. Github 2016.

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