Predicting Resistance by Mutagenesis: Lessons from 45 Years of MBC Resistance

A - Papers appearing in refereed journals

Hawkins, N. J. and Fraaije, B. A. 2016. Predicting Resistance by Mutagenesis: Lessons from 45 Years of MBC Resistance. Frontiers in Microbiology. 7, p. 1814.

AuthorsHawkins, N. J. and Fraaije, B. A.

When a new fungicide class is introduced, it is useful to anticipate the resistance risk in advance, attempting to predict both risk level and potential mechanisms. One tool for the prediction of resistance risk is laboratory selection for resistance, with the mutational supply increased through UV or chemical mutagenesis. This enables resistance to emerge more rapidly than in the field, but may produce mutations that would not emerge under field conditions. The methyl benzimidazole carbamates (MBCs) were the first systemic single-site agricultural fungicides, and the first fungicides affected by rapid evolution of target-site resistance. MBC resistance has now been reported in over 90 plant pathogens in the field, and laboratory mutants have been studied in nearly 30 species. The most common field mutations, including β-tubulin E198A/K/G, F200Y and L240F, have all been identified in laboratory mutants. However, of 28 mutations identified in laboratory mutants, only nine have been reported in the field. Therefore, the predictive value of mutagenesis studies would be increased by understanding which mutations are likely to emerge in the field. Our review of the literature indicates that mutations with high resistance factors, and those found in multiple species, are more likely to be reported in the field. However, there are many exceptions, possibly due to fitness penalties. Whether a mutation occurred in the same species appears less relevant, perhaps because β-tubulin is highly conserved so functional constraints are similar across all species. Predictability of mutations in other target sites will depend on the level and conservation of constraints.

Keywordsfungicide resistance; plant pathogens; benzimidazoles; mutagenesis; in vitro selection; predictability; fitness penalties; functional constraints
Year of Publication2016
JournalFrontiers in Microbiology
Journal citation7, p. 1814
Digital Object Identifier (DOI)
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeSustainability
Understanding pesticide resistance and developing sustainable crop protection strategies
Publisher's version
Copyright license
Output statusPublished
Publication dates
Online15 Nov 2016
Publication process dates
Accepted28 Oct 2016
PublisherFrontiers Media SA

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