Spatio‐temporal distribution of DMI and SDHI fungicide resistance of Zymoseptoria tritici throughout Europe based on frequencies of key target‐site alterations

• Published in: Pest management science Vol. 77; no. 12; pp. 5576 - 5588
• Main Authors: Hellin, Pierre, Duvivier, Maxime, Heick, Thies M, Fraaije, Bart A, Bataille, Charlotte, Clinckemaillie, Aurélie, Legrève, Anne, Jørgensen, Lise N, Andersson, Björn, Samils, Berit, Rodemann, Bernd, Berg, Gunilla, Hutton, Fiona, Garnault, Maxime, El Jarroudi, Moussa, Couleaud, Gilles, Kildea, Steven
• Format: Journal Article Web Resource
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.12.2021; Wiley Subscription Services, Inc; Wiley; John Wiley & Sons
• Subjects: Agricultural Science; Agriculture & agronomie; Agriculture & agronomy; Ascomycota; Demethylation; Deoxyribonucleic acid; disease control; DNA; Environmental Sciences; Europe; Fungicides; Fungicides, Industrial - pharmacology; Inhibitors; Jordbruksvetenskap; Leaves; Life Sciences; Mycosphaerella graminicola; Pesticides; Phenotyping; Plant Diseases; Sciences du vivant; sensitivity; Septoria tritici blotch; Succinate dehydrogenase; Succinate Dehydrogenase - genetics; Succinic Acid; Temporal distribution; triazole; Triazoles; Wheat; Zymoseptoria tritici; Europe; United Kingdom > UK; Ireland; disease control; wheat; Mycosphaerella graminicola; sensitivity; septoria tritici blotch; triazole; ensitivity; Mycosphaerella graminicolas
• ISSN: 1526-498X; 1526-4998; 1526-4998
• DOI: 10.1002/ps.6601

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. CONCLUSION Whilst these alterations are quickly becoming dominant in Ireland and Great Britain, scope still exists to delay their selection throughout the wider European population, emphasizing the need for the implementation of fungicide antiresistance measures. © 2021 Society of Chemical Industry. Analysis of wheat leaves colonized by Zymoseptoria tritici revealed the presence of a European 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. Investigations on historical leaf DNA samples originating from different European countries showed that the frequency of all key alterations (except C‐T79I) has been gradually increasing over the past decade.