Screening for QoI resistance in UK populations of Rhynchosporium secalis

Summary

Sector:
Cereals & Oilseeds
Project code:
PR482
Date:
01 June 2009 - 31 December 2010
Funders:
AHDB Cereals & Oilseeds.
AHDB sector cost:
£55,257 from HGCA.
Project leader:
J. M. Fountaine SAC, West Mains Road, Edinburgh EH9 3JG

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About this project

Abstract

The development of strobilurin (QoI (quinone outside inhibitors)) fungicide resistance is now widespread in many fungal plant pathogens. However, this group of fungicides is still widely used to controlRhynchosporium secalis in winter and spring barley crops across the UK and have so far retained their efficacy. Resistance to this fungicide group in the majority of fungal pathogens is the result of a single point mutation found at either codon 143, 129 or 137 in the cytochrome b gene. During 2008, routine screening of the R. secalis populations by BASF discovered that some isolates in northern France had developed a mutation at codon 143.

This research examined the UK population of R. secalis over two growing seasons (2009-2010) for the occurrence of the mutations causing resistance to QoI fungicides with the combined use of molecular techniques and 96 well plate fungicide sensitivity assays During this project, a high throughput pyrosequencing assay was developed to examine populations directly from field samples. This coupled with the fungicide bioassays and a simple Polymerase Chain Reaction Random Amplified Length Polymorphism (PCR-RFLP), (a simple enzyme methodology that cuts DNA into small parts only if mutations causing fungicide resistance are present) indicated that the UK R. secalis population remained fully sensitive to QoI fungicides during the period of this project (2008-2010) with no declines in efficacy. However, this does not mean that resistance will not develop in the coming years and ongoing independent screening will be required to monitor the situation in the coming growing seasons.

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