Sensitivity of California Isolates of <i>Uncinula necator</i> to Trifloxystrobin and Spiroxamine, and Update on Triadimefon Sensitivity

Miller, T.; Gubler, W. D.

doi:10.1094/pdis.2004.88.11.1205

Cited by 20 publications

(10 citation statements)

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“…The methods for maintaining PM isolates and perfortning bioassays were adapted from those described by Gubler et al (9), Erickson and Wilcox (6), Ypema et al (21 ), Miller and Gubler (11), and Wong and Wilcox (20).…”

Section: Methodsmentioning

confidence: 99%

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Sensitivity of Erysiphe necator to Demethylation Inhibitor Fungicides in Virginia

2012

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Colcol, J. F., Rallos, L. E., and Baudoin, A. B. 2012. Sensitivity of Erysiphe neeator to demethylation inhibitor fungicides in Virginia. Plant Dis. 96:111-116.Grape powdery mildew {Erysiphe necator) isolates were collected from 2(K)5 to 2007 from vineyards mostly in Virginia but also some in Maryland, North Carolina, and Pennsylvania. Using a leaf disc assay, the isolates were tested against five demethylation inhibitor (DMI) fungicides. Most isolates exhibited reduced sensitivity to the live DMIs when compared with a sensitive group (H = 12) and compared with unexposed populations reported from other areas. The median resistance factor (RF) was highest for tebucona/ole (RF = 399) and myclobutanil (RF = 378), followed by tritlumizole (RF = 70), triadimefon (RF = 62), and fenarimol (RF = 44). Tbe sensitive group used as the basis for comparison appears to have been more sensitive than unexposed isolates in New York and California. Our finding that the greatest resistance shift occurred with tebucona/ole and myclobutanil contrasts with earlier reports from New York and California, whore the greatest resistance shift was observed with triadinielbn or triadimenol. Sensitivities to all five DMI fungicides were strongly correlated (pairwise r values of 0.70 to 0.87) but our data suggest that some may retain greater utility than others.

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Section: Methodsmentioning

confidence: 99%

“…Miller and Gubler (11) reported that triadimefon resistance in California in 2002 was still high (tnean ECso of 8.8 pg/ml), even alter many years of little use. Miller and Gubler (11) reported that triadimefon resistance in California in 2002 was still high (tnean ECso of 8.8 pg/ml), even alter many years of little use.…”

Section: Resistance Factormentioning

confidence: 99%

Sensitivity of Erysiphe necator to Demethylation Inhibitor Fungicides in Virginia

2012

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“…[21][22][23] Trifloxystrobin, a member of the QoI group, has translaminar and redistribution properties in plants and can provide excellent protective and curative efficacy against plant pathogens. [24][25][26] Also, it has a favorable toxicological profile and is unlikely to cause any undue hazard to non-target organisms. 27 Recently, trifloxystrobin has been formally registered for control of M. oryzae in China (China Pesticide Information Network, http://www.chinapesticide.org.cn).…”

Section: Introductionmentioning

confidence: 99%

Three point‐mutations in cytochrome b confer resistance to trifloxystrobin in Magnaporthe oryzae

Miao

Zhao

Wang

et al. 2020

Pest Management Science

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BACKGROUND: Rice blast, caused by Magnaporthe oryzae, is the most devastating disease in rice. Recently, trifloxystrobin was registered for the control of M. oryzae in China. The resistance profile and mechanism of M. oryzae to trifloxystrobin were investigated in the present study, providing important data for the recommended use of trifloxystrobin. RESULTS: The baseline sensitivity was established at a half maximal effective concentration (EC 50) of 0.024 ∼g mL −1. Nine stable trifloxystrobin-resistant mutants were generated with EC 50 values ranging from 12.75 to 171.49 ∼g mL −1. The mutants exhibited strong adaptive traits in sporulation, conidial germination, and pathogenicity. Positive cross-resistance was only observed between trifloxystrobin and azoxystrobin, but not between trifloxystrobin and carbendazim, isoprothiolane, prochloraz, or chlorothalonil. The point mutation G143S in cytochrome b (cyt b) protein was found in eight high-resistance mutants with resistant factor ranging from 2295.16 to 13 200.00; and the double mutation G137R/M296V only occurred in Mg117-1 with resistance factor ≈ 900. The G143S mutation weakened hydrogen bond interactions, and G137R/M296V changed the conformation of trifloxystrobin in the cyt b binding pocket. A molecular detection method was established for the rapid detection of G143S mutants in M. oryzae. CONCLUSION: The resistance risk of M. oryzae to trifloxystrobin could be moderate to high. Two genotypes with three pointmutations G143S, G137R, and M296V conferred resistance to trifloxystrobin in M. oryzae.

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“…DMIs are prone to resistance issues due to their single metabolic target. Triadimefon was the first DMI fungicide to be approved for powdery mildew control in vineyards in 1982, and resistance was documented as soon as 1986 [ 9 , 13 ]. Resistance to other DMIs has since been reported, including cross-resistance between different compounds [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Adaptive genomic structural variation in the grape powdery mildew pathogen, Erysiphe necator

et al. 2014

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BackgroundPowdery mildew, caused by the obligate biotrophic fungus Erysiphe necator, is an economically important disease of grapevines worldwide. Large quantities of fungicides are used for its control, accelerating the incidence of fungicide-resistance. Copy number variations (CNVs) are unbalanced changes in the structure of the genome that have been associated with complex traits. In addition to providing the first description of the large and highly repetitive genome of E. necator, this study describes the impact of genomic structural variation on fungicide resistance in Erysiphe necator.ResultsA shotgun approach was applied to sequence and assemble the genome of five E. necator isolates, and RNA-seq and comparative genomics were used to predict and annotate protein-coding genes. Our results show that the E. necator genome is exceptionally large and repetitive and suggest that transposable elements are responsible for genome expansion. Frequent structural variations were found between isolates and included copy number variation in EnCYP51, the target of the commonly used sterol demethylase inhibitor (DMI) fungicides. A panel of 89 additional E. necator isolates collected from diverse vineyard sites was screened for copy number variation in the EnCYP51 gene and for presence/absence of a point mutation (Y136F) known to result in higher fungicide tolerance. We show that an increase in EnCYP51 copy number is significantly more likely to be detected in isolates collected from fungicide-treated vineyards. Increased EnCYP51 copy numbers were detected with the Y136F allele, suggesting that an increase in copy number becomes advantageous only after the fungicide-tolerant allele is acquired. We also show that EnCYP51 copy number influences expression in a gene-dose dependent manner and correlates with fungal growth in the presence of a DMI fungicide.ConclusionsTaken together our results show that CNV can be adaptive in the development of resistance to fungicides by providing increasing quantitative protection in a gene-dosage dependent manner. The results of this work not only demonstrate the effectiveness of using genomics to dissect complex traits in organisms with very limited molecular information, but also may have broader implications for understanding genomic dynamics in response to strong selective pressure in other pathogens with similar genome architectures.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-1081) contains supplementary material, which is available to authorized users.

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Sensitivity of California Isolates of Uncinula necator to Trifloxystrobin and Spiroxamine, and Update on Triadimefon Sensitivity

Cited by 20 publications

References 37 publications

Sensitivity of Erysiphe necator to Demethylation Inhibitor Fungicides in Virginia

Sensitivity of Erysiphe necator to Demethylation Inhibitor Fungicides in Virginia

Three point‐mutations in cytochrome b confer resistance to trifloxystrobin in Magnaporthe oryzae

Adaptive genomic structural variation in the grape powdery mildew pathogen, Erysiphe necator

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