Parallel evolution of multiple mechanisms for demethylase inhibitor fungicide resistance in the barley pathogen<i>Pyrenophora teres</i>f. sp.<i>maculata</i>

Mair, Wesley J.; Thomas, Geoffrey J.; Dodhia, Kejal N; Hills, Andrea; Jayasena, K. W.; Ellwood, Simon R.; Oliver, Richard P.; Lopez‐Ruiz, Francisco J.

doi:10.1101/798991

Cited by 2 publications

(10 citation statements)

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“…teres (Ellwood et al 2019;Mair et al 2019). Considering the importance of these genes for fungal virulence/pathogenicity, it is plausible that mutations at these loci are due to external effects such as environmental factors and fungicide regimes.…”

Section: Discussionmentioning

confidence: 99%

Population Structure of Pyrenophora teres f. teres Barley Pathogens from Different Continents

et al. 2021

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Net-form net blotch disease caused by Pyrenophora teres f. teres (Ptt) results in significant yield losses to barley industries. Up-to-date knowledge of the genetic diversity and structure of pathogen populations is critical for better understanding the disease epidemiology and unravelling pathogen survival and dispersal mechanisms. Thus, this study investigated long distance dispersal and adaptation by analysing the genetic structure of 250 Ptt isolates collected from Australia, Canada, Hungary and Republic of South Africa (RSA), and historical isolates from Canada, Denmark, Japan and Sweden. The population genetic structure detected by discriminant analysis of principal component, using 5890 Diversity Arrays Technology (DArT) markers, revealed the presence of four clusters. Two of these contained isolates from all regions, and all isolates from RSA were grouped in these two. Australia and Hungary showed three clusters each. One of the Australian clusters contained only Australian isolates. One of the Hungarian clusters contained only Hungarian isolates and one Danish isolate. STRUCTURE analysis indicated that some isolates from Australia and Hungary shared recent ancestry with RSA, Canada and historical isolates and were thus admixed. Subdivisions of the Neighbor-joining network indicated that isolates from distinct countries were closely related, suggesting multiple introduction events conferred genetic heterogeneity in these countries. Through a Neighbor-joining analysis and amplification with form-specific DNA markers two hybrid isolates, CBS 281.31 from Japan and H-919 from Hungary collected in 1931 and 2018, respectively, were detected. These results provide a foundation for exploring improved management of disease incursions and pathogen control through strategic deployment of resistances.

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Section: Discussionmentioning

confidence: 99%

Population Structure of Pyrenophora teres f. teres Barley Pathogens from Different Continents

et al. 2021

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“…The design of a duplex PCR assay for simultaneous specific identification of P. teres f. maculata and P. teres f. teres was based on form-specific DNA regions described by Mair et al (2023).…”

Section: Pyrenophora Teres Form-specific Pcr Designmentioning

confidence: 99%

“…In Australia, fungicide resistance in the barley (Hordeum vulgare) pathogen Pyrenophora teres has become an important management issue (Ellwood et al 2019;Mair et al 2016;Mair et al 2020;Mair et al 2023). Pyrenophora teres is recognised as two forms, P. teres f. teres and P. teres f. maculata, causing net form net blotch (NFNB) and spot form net blotch (SFNB), respectively (Smedegård-Petersen 1971).…”

Section: Introductionmentioning

confidence: 99%

“…The copyright holder for this preprint (which this version posted April 28, 2023. ; https://doi.org/10.1101/2023.04.27.538624 doi: bioRxiv preprint bioRxiv 2019; Mair et al 2016;Mair et al 2020;, SDHI (Mair et al 2023;Rehfus et al 2016) and QoI fungicides (Marzani et al 2013;Semar et al 2007;Sierotzki et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Genotypes of P. teres associated with sensitivity, reduced sensitivity and resistance have been reported for DMI, SDHI and QoI fungicides. These include single nucleotide polymorphisms (SNPs) in the genes for cytochrome P450 sterol 14α-demethylase (CYP51A) (Mair et al 2016), the succinate dehydrogenase (SDH) B, C and D sub-units (Mair et al 2023;Rehfus et al 2016) and cytochrome b (Sierotzki et al 2007), along with a range of 134 bp insertions in the Cyp51A promoter region (Mair et al 2020). Detection of these genotypes may be achieved using methods such as pyrosequencing (Gobeil-Richard et al 2016;Santos et al 2020) and real-time or digital PCR (Capote et al 2012;Hellin et al 2020;Zulak et al 2018).…”

Section: Introductionmentioning

confidence: 99%

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Workflows for detecting fungicide resistance in net form and spot form net blotch pathogens

Knight¹,

Adhikari²,

Dodhia³

et al. 2023

Preprint

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Fungicide resistance in Pyrenophora teres f. maculata and P. teres f. teres has become an important disease management issue. Control of the associated barley foliar diseases, spot form and net form net blotch, respectively, relies on three major groups of fungicides, demethylation inhibitors (DMI), succinate dehydrogenase inhibitors (SDHI) and quinone outside inhibitors (QoI). However, resistance has been reported for the DMI and SDHI fungicides in Australia. To enhance detection of different resistance levels, phenotyping and genotyping workflows were designed. The phenotyping workflow generated cultures directly from lesions and compared growth on discriminatory doses of tebuconazole (DMI) and fluxapyroxad (SDHI). Genotyping real-time PCR assays were based on alleles associated with sensitivity or resistance to the DMI and SDHI fungicides. These workflows were applied to a net blotch collection from 2019 consisting predominantly of P. teres f. teres from South Australia and P. teres f. maculata from Western Australia. For South Australia the Cyp51A L489-3 and SdhC-R134 alleles, associated with resistance to tebuconazole and fluxapyroxad, respectively, were the most prevalent. These alleles were frequently found in single isolates with dual resistance. This study also reports the first detection of a 134 base pair insertion located at position -66 (PtTi-6) in the Cyp51A promoter of P. teres f. maculata from South Australia. For Western Australia, the PtTi-1 insertion was the most common allele associated with resistance to tebuconazole. These workflows will be valuable for screening P. teres populations for fungicide resistance, and informing appropriate management strategies.

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Parallel evolution of multiple mechanisms for demethylase inhibitor fungicide resistance in the barley pathogenPyrenophora teresf. sp.maculata

Cited by 2 publications

References 58 publications

Population Structure of Pyrenophora teres f. teres Barley Pathogens from Different Continents

Population Structure of Pyrenophora teres f. teres Barley Pathogens from Different Continents

Workflows for detecting fungicide resistance in net form and spot form net blotch pathogens

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