Non‐target site SDHI resistance is present as standing genetic variation in field populations of Zymoseptoria tritici

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Yamashita, M. and Fraaije, B. A. 2018. Non‐target site SDHI resistance is present as standing genetic variation in field populations of Zymoseptoria tritici. Pest Management Science. 74 (3), pp. 672-681.

AuthorsYamashita, M. and Fraaije, B. A.

BACKGROUND A new generation of more active succinate dehydrogenase (Sdh) inhibitors (SDHIs) is currently widely used to control Septoria leaf blotch in northwest Europe. Detailed studies were conducted on Zymoseptoria tritici field isolates with reduced sensitivity to fluopyram and isofetamid; SDHIs which have only just or not been introduced for cereal disease control, respectively. RESULTS Strong cross‐resistance between fluopyram and isofetamid, but not with other SDHIs, was confirmed through sensitivity tests using laboratory mutants and field isolates with and without Sdh mutations. The sensitivity profiles of most field isolates resistant to fluopyram and isofetamid were very similar to a lab mutant carrying SdhC‐A84V, but no alterations were found in SdhB, C and D. Inhibition of mitochondrial Sdh enzyme activity and control efficacy in planta for those isolates was severely impaired by fluopyram and isofetamid, but not by bixafen. Isolates with similar phenotypes were not only detected in northwest Europe but also in New Zealand before the widely use of SDHIs. CONCLUSION This is the first report of SDHI‐specific non‐target site resistance in Z. tritici. Monitoring studies show that this resistance mechanism is present and can be selected from standing genetic variation in field populations. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

KeywordsSeptoria leaf blotch; Fungicide resistance; Succinate dehydrogenase inhibitor; Fluopyram; Isofetamid
Year of Publication2018
JournalPest Management Science
Journal citation74 (3), pp. 672-681
Digital Object Identifier (DOI)
Open accessPublished as ‘gold’ (paid) open access
FunderDepartment of Environment, Food and Rural Affairs
Biotechnology and Biological Sciences Research Council
Publisher's version
Output statusPublished
Publication dates
Online10 Oct 2017
Publication process dates
Accepted29 Sep 2017
Copyright licenseCC BY

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