Lack of cross-resistance to a novel succinate dehydrogenase inhibitor, fluopyram, in highly boscalid-resistant isolates of Corynespora cassiicola and Podosphaera xanthii

2011 ◽  
Vol 67 (4) ◽  
pp. 474-482 ◽  
Author(s):  
Hideo Ishii ◽  
Takuya Miyamoto ◽  
Shingo Ushio ◽  
Makoto Kakishima
Keyword(s):  
Succinate Dehydrogenase ◽  
Cross Resistance ◽  
Corynespora Cassiicola ◽  
Podosphaera Xanthii ◽  
Succinate Dehydrogenase Inhibitor

Activity of A Novel Succinate Dehydrogenase Inhibitor Fungicide Pydiflumetofen against Fusarium fujikuroi causing Rice Bakanae Disease

Plant Disease ◽  
2021 ◽  
Author(s):  
Yang Bai ◽  
Chun-Yan Gu ◽  
Rui Pan ◽  
Muhammad Abid ◽  
Hao-Yu Zang ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Succinate Dehydrogenase ◽  
Field Trials ◽  
Cell Membrane Permeability ◽  
Cross Resistance ◽  
Fusarium Fujikuroi ◽  
Control Efficacy ◽  
Bakanae Disease ◽  
Geographical Regions ◽  
Succinate Dehydrogenase Inhibitor

New fungicides are tools to manage fungal diseases and overcome emerging resistance in fugnal pathogens. In this study, a total of 121 isolates of Fusarium fujikuroi, the causal agent of rice bakanae disease (RBD), were collected from various geographical regions of China, and their sensitivity to a novel succinate dehydrogenase inhibitor (SDHI)fungicide ‘pydiflumetofen’ was evaluated. The 50% effective concentration (EC50) value of pydiflumetofen for mycelial growth suppression ranged from 0.0101 to 0.1012 μg/ml and for conidial germination inhibition ranged from 0.0051to 0.1082 μg/ml. Pydiflumetofen treated hyphae showed contortion and increased branching, cell membrane permeability, and glycerol content significantly. The result of electron microscope transmission indicated that pydiflumetofen damaged the mycelial cell wall and the cell membrane, and almost broken up the cells, which increased the intracellular plasma leakage. There was no cross-resistance between pydiflumetofen and the widely used fungicides such as carbendazim, prochloraz, and phenamacril. Pydiflumetofen was found safe to seeds and rice seedlings of four rice cultivars, used up to 400 μg/ml. Seed treatment significantly decreased the rate of diseased plants in the greenhouse as well as in field trials in 2017 and 2018. Pydiflumetofen showed superb results against RBD, when used at 10 or 20 g a.i./100 kg of treated seeds, providing over 90% control efficacy (the highest control efficacy was up to 97%), which was significantly higher than that of 25% phenamacril (SC) at 10g or carbendazim at 100 g. Pydiflumetofen is highly effective against F. fujikuroi growth and sporulation as well as RBD in the field.

scholarly journals Occurrence, Distribution, and Characteristics of Boscalid-Resistant Corynespora cassiicola in China

Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Fadi Zhu ◽  
Yanxia Shi ◽  
Xuewen Xie ◽  
Ali Chai ◽  
Baoju Li
Keyword(s):  
Growth Inhibition ◽  
Succinate Dehydrogenase ◽  
Frequency Distribution ◽  
Mycelial Growth ◽  
Corynespora Cassiicola ◽  
Baseline Sensitivity ◽  
Resistance Patterns ◽  
Moderately Resistant ◽  
Succinate Dehydrogenase Inhibitor ◽  
Important Disease

Corynespora blight, caused by Corynespora cassiicola (Berk. & M.A. Curtis) C.T. Wei, has become an important disease affecting cucumber in China. Its management mainly depends on fungicides; however, no research has been conducted to assess the sensitivity of C. cassiicola in China to boscalid, a succinate dehydrogenase inhibitor (SDHI). To facilitate boscalid resistance monitoring, baseline sensitivity was established. The EC50 value (i.e., the concentration that results in 50% mycelial growth inhibition) frequency distribution was unimodal with a right-hand tail; with the means 0.95 ± 0.51 μg/ml and the range 0.03 to 2.85 μg/ml. We then assessed the sensitivity of C. cassiicola to boscalid using discriminatory doses and EC50 values. In total, 27.8% of the 798 isolates were resistant, distributed in five provinces and two municipalities. Thirty-seven isolates with different resistance levels to boscalid were also evaluated for their sensitivity to carboxin, fluopyram, and penthiopyrad. Seven SDHI resistance patterns were observed (i.e., I: BosMRFluoMRPenLRCarSS; II: BosVHRFluoSSPenMRCarR; III: BosLRFluoMRPenLRCarR; IV: BosMRFluoMRPenMRCarR; V: BosHRFluoMRPenHRCarR; VI: BosHRFluoHRPenHRCarR; and VII: BosHRFluoSSPenLR CarR, VHR: very highly resistant; HR: highly resistant; MR: moderately resistant; LR: low resistant; R: resistant; SS: supersensitive), corresponding to seven mutations in sdhB/C/D genes, respectively.

scholarly journals A Review of Current Knowledge of Resistance Aspects for the Next-Generation Succinate Dehydrogenase Inhibitor Fungicides

2013 ◽  
Vol 103 (9) ◽  
pp. 880-887 ◽  
Author(s):  
Helge Sierotzki ◽  
Gabriel Scalliet
Keyword(s):  
Succinate Dehydrogenase ◽  
Mode Of Action ◽  
Fungal Pathogens ◽  
Current Knowledge ◽  
Field Performance ◽  
Population Level ◽  
Tca Cycle ◽  
Cross Resistance ◽  
Docking Simulations ◽  
Succinate Dehydrogenase Inhibitor

The new broad-spectrum fungicides from the succinate dehydrogenase inhibitor (SDHI) class have been quickly adopted by the market, which may lead to a high selection pressure on various pathogens. Cases of resistance have been observed in 14 fungal pathogens to date and are caused by different mutations in genes encoding the molecular target of SDHIs, which is the mitochondrial succinate dehydrogenase (SDH) enzyme. All of the 17 marketed SDHI fungicides bind to the same ubiquinone binding site of the SDH enzyme. Their primary biochemical mode of action is the blockage of the TCA cycle at the level of succinate to fumarate oxidation, leading to an inhibition of respiration. Homology models and docking simulations explain binding behaviors and some peculiarities of the cross-resistance profiles displayed by different members of this class of fungicides. Furthermore, cross-resistance patterns among SDHIs is complex because many mutations confer full cross resistance while others do not. The nature of the mutations found in pathogen populations varies with species and the selection compound used but cross resistance between all SDHIs has to be assumed at the population level. In most of the cases where resistance has been reported, the frequency is still too low to impact field performance. However, the Fungicide Resistance Action Committee has developed resistance management recommendations for pathogens of different crops in order to reduce the risk for resistance development to this class of fungicides. These recommendations include preventative usage, mixture with partner fungicides active against the current pathogen population, alternation in the mode of action of products used in a spray program, and limitations in the total number of applications per season or per crop.

scholarly journals Double Mutations in Succinate Dehydrogenase Are Involved in SDHI Resistance in Corynespora cassiicola

2022 ◽  
Vol 10 (1) ◽  
pp. 132
Author(s):  
Bingxue Sun ◽  
Guangxue Zhu ◽  
Xuewen Xie ◽  
Ali Chai ◽  
Lei Li ◽  
...  
Keyword(s):  
Succinate Dehydrogenase ◽  
Point Mutation ◽  
Single Point ◽  
Resistance Management ◽  
Site Directed Mutagenesis ◽  
Single Point Mutation ◽  
Single Mutation ◽  
Corynespora Cassiicola ◽  
Double Mutation ◽  
Mutation Analyses

With the further application of succinate dehydrogenase inhibitors (SDHI), the resistance caused by double mutations in target gene is gradually becoming a serious problem, leading to a decrease of control efficacy. It is important to assess the sensitivity and fitness of double mutations to SDHI in Corynespora cassiicola and analysis the evolution of double mutations. We confirmed, by site-directed mutagenesis, that all double mutations (B-I280V+D-D95E/D-G109V/D-H105R, B-H278R+D-D95E/D-G109V, B-H278Y+D-D95E/D-G109V) conferred resistance to all SDHI and exhibited the increased resistance to at least one fungicide than single point mutation. Analyses of fitness showed that all double mutations had lower fitness than the wild type; most of double mutations suffered more fitness penalties than the corresponding single mutants. We also further found that double mutations (B-I280V+D-D95E/D-G109V/D-H105R) containing low SDHI-resistant single point mutation (B-I280V) exhibited higher resistance to SDHI and low fitness penalty than double mutations (B-H278Y+D-D95E/D-G109V) containing high SDHI-resistant single mutations (B-H278Y). Therefore, we may infer that a single mutation conferring low resistance is more likely to evolve into a double mutation conferring higher resistance under the selective pressure of SDHI. Taken together, our results provide some important reference for resistance management.

scholarly journals Succinate dehydrogenase inhibitor (SDHI) fungicide resistance prevention strategy

2011 ◽  
Vol 64 ◽  
pp. 119-124 ◽  
Author(s):  
A.H. McKay ◽  
G.C. Hagerty ◽  
G.B. Follas ◽  
M.S. Moore ◽  
M.S. Christie ◽  
...  
Keyword(s):  
New Zealand ◽  
High Risk ◽  
Succinate Dehydrogenase ◽  
Fungicide Resistance ◽  
Fungal Pathogens ◽  
Resistance Management ◽  
Resistance Development ◽  
Development Of Resistance ◽  
Action Committee ◽  
Succinate Dehydrogenase Inhibitor

Succinate dehydrogenase inhibitor (SDHI) fungicides are currently represented in New Zealand by eight active ingredients bixafen boscalid carboxin fluaxapyroxad fluopyram isopyrazam penthiopyrad and sedaxane They are either currently registered or undergoing development in New Zealand for use against a range of ascomycete and basiodiomycete pathogens in crops including cereals ryegrass seed apples pears grapes stonefruit cucurbits and kiwifruit These fungicides are considered to have medium to high risk of resistance development and resistance management is recommended by the Fungicide Resistance Action Committee (FRAC) in Europe Guidelines are presented for use of SDHI fungicides in New Zealand to help avoid or delay the development of resistance in the fungal pathogens that they target

scholarly journals Resistance to Fluopyram, Fluxapyroxad, and Penthiopyrad in Botrytis cinerea from Strawberry

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 532-539 ◽  
Author(s):  
Achour Amiri ◽  
Stacy M. Heath ◽  
Natalia A. Peres
Keyword(s):  
Succinate Dehydrogenase ◽  
Botrytis Cinerea ◽  
High Resistance ◽  
Gray Mold ◽  
Cross Resistance ◽  
The Novel ◽  
Resistance Development ◽  
Dehydrogenase Gene ◽  
Resistance Patterns ◽  
Subunit B

Succinate dehydrogenase inhibitors (SDHIs) constitute a mainstay in management of gray mold caused by Botrytis cinerea in strawberry and several other crops. In this study, we investigated the risks of resistance development to three newer SDHIs (i.e., fluopyram, fluxapyroxad, and penthiopyrad) and their cross-resistance with the previously registered boscalid. We investigated the mutations in the SdhB subunit and evaluated their impact on microbial fitness in field populations of B. cinerea. Amino acid substitutions associated with resistance to SDHIs were detected at three codons of the SdhB subunit (BH272R/Y/L, BP225F, and BN230I) in the succinate dehydrogenase gene of field isolates from Florida. The BH272R, BH272Y, BH272L, BP225F, and BN230I mutations were detected at frequencies of 51.5, 28.0, 0.5, 2.5, and 4%, respectively. Strong cross-resistance patterns were evident between boscalid and fluxapyroxad and penthiopyrad but not with fluopyram, except in BH272L, BP225F, and BN230I mutants. All five mutations conferred moderate to very high resistance to boscalid whereas the BH272Y conferred resistance to fluxapyroxad and penthiopyrad. The BH272L, BN230I, and BP225F mutations conferred high resistance to all four SDHIs tested. Resistance monitoring following the first use of penthiopyrad in strawberry fields in Florida in 2013 suggests potential for quick selection for highly resistant populations and warrants careful use of the newer SDHIs. No evidence of major fitness costs due to the mutations in the SdhB subunit was found, which indicates the potential ability of the mutants to survive and compete with wild-type isolates. Our study suggests high risks for rapid widespread occurrence of B. cinerea populations resistant to the novel SDHIs unless appropriate rotation strategies are implemented immediately upon registration.

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