Abstract :
[en] BACKGROUND: Over the past decade, demethylation inhibitor (DMI) and succinate dehydrogenase inhibitor (SDHI) fungicides
have been extensively used to control to septoria tritici blotch, caused by Zymoseptoria tritici on wheat. This has led to the
development and selection of alterations in the target-site enzymes (CYP51 and SDH, respectively).
RESULTS: Taking advantage of newly and previously developed qPCR assays, the frequency of key alterations
associated with DMI (CYP51-S524T) and SDHI (SDHC-T79N/I, C-N86S and C-H152R) resistance was assessed in
Z. tritici-infected wheat leaf samples collected from commercial crops (n = 140) across 14 European countries prior
to fungicide application in the spring of 2019. This revealed the presence of a West to East gradient in the frequencies
of the most common key alterations conferring azole (S524T) and SDHI resistance (T79N and N86S), with the
highest frequencies measured in Ireland and Great Britain. These observations were corroborated by sequencing
(CYP51 and SDH subunits) and sensitivity phenotyping (prothioconazole-desthio and fluxapyroxad) of Z. tritici isolates
collected from a selection of field samples. Additional sampling made at the end of the 2019 season confirmed the
continued increase in frequency of the targeted alterations. Investigations on historical leaf DNA samples originating
from different European countries revealed that the frequency of all key alterations (except C-T79I) has been gradually
increasing over the past decade.
Scopus citations®
without self-citations
9