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Alternative oxidase reduces the sensitivity of Mycosphaerella graminicola to QOI fungicides
Author(s) -
Miguez Monica,
Reeve Charlotte,
Wood Paul M,
Hollomon Derek W
Publication year - 2004
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.837
Subject(s) - azoxystrobin , fungicide , biology , alternative oxidase , strobilurin , horticulture , mycosphaerella graminicola , botany , respiration
Abstract Forty‐six (1.5%) of nearly 3000 isolates of Mycosphaerella graminicola assayed in vitro were resistant to the QOI fungicide azoxystrobin, but on sub‐culturing only ten remained resistant. Cross‐resistance extended to other QOIs, but varied between different isolates. In planta the resistant isolates were not well controlled, especially at lower azoxystrobin dose rates. Propyl gallate, an inhibitor of alternative oxidase, potentiated the activity of azoxystrobin in vitro so that resistance was no longer observed. The growth of resistant strains in the presence of azoxystrobin led to alternative oxidase activation. This increased flexibility in respiration allows resistant strains to survive in the presence of a QOI fungicide. Under these conditions, selection for target‐site mutations can occur. Using QOIs preventatively reduces the risk of resistance since the alternative oxidase cannot by itself generate all the energy needed for germination and early infection. Copyright © 2003 Society of Chemical Industry