Point Mutations in FgSdhC2 or in the 5′ Untranslated Region of FgSdhC1 Confer Resistance to a Novel Succinate Dehydrogenase Inhibitor Flubeneteram in Fusarium graminearum

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.

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Succinate dehydrogenase inhibitor (SDHI) fungicide resistance prevention strategy

New Zealand Plant Protection ◽

10.30843/nzpp.2011.64.5972 ◽

2011 ◽

Vol 64 ◽

pp. 119-124 ◽

Cited By ~ 4

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

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Bixafen, a succinate dehydrogenase inhibitor fungicide, causes microcephaly and motor neuron axon defects during development

Chemosphere ◽

10.1016/j.chemosphere.2020.128781 ◽

2021 ◽

Vol 265 ◽

pp. 128781

Author(s):

Alexandre Brenet ◽

Rahma Hassan-Abdi ◽

Nadia Soussi-Yanicostas

Keyword(s):

Motor Neuron ◽

Succinate Dehydrogenase ◽

Succinate Dehydrogenase Inhibitor

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Resistance to boscalid in Botrytis cinerea from greenhouse grown tomato

Plant Disease ◽

10.1094/pdis-06-20-1191-re ◽

2020 ◽

Author(s):

Shengming Liu ◽

Liuyuan Fu ◽

Huanhuan Tan ◽

Jia Jiang ◽

Zhiping Che ◽

...

Keyword(s):

Succinate Dehydrogenase ◽

Botrytis Cinerea ◽

Mycelial Growth ◽

Point Mutations ◽

Dry Weight ◽

Henan Province ◽

Cross Resistance ◽

Tomato Production ◽

Grey Mold ◽

Moderately Resistant

Grey mold, caused by the fungus Botrytis cinerea Pers ex Fr., is one of the most destructive spoilage diseases, severely affecting tomato production in Henan Province, China. Spraying fungicides from the flowering to the harvest stage is a necessary measure to reduce losses associated with B. cinerea infection. However, B. cinerea has developed resistance to fungicides in many countries. Boscalid is a succinate dehydrogenase inhibitor (SDHI) fungicide, and was registered for the control of grey mold. In this study, a total of 269 B. cinerea isolates were collected from tomato in commercial greenhouses in different locations of Henan Province, in 2014 and 2015. The sensitivity and resistance of B. cinerea field isolates were determined based on mycelial growth. The effective concentration 50 (EC50) ranged from 0.11 to 15.92 μg ml−1 and 0.16 to 8.54 μg ml−1, in 2014 and 2015, respectively. The frequency of low resistance to boscalid was 12.6% and 7.6%, and moderate resistance were 2.7% and 1.3%, in 2014 and 2015, respectively. No high-resistant isolates were found in Henan Province, China. Mycelial growth, mycelial dry weight, spore production, and pathogenicity were not significantly different between resistant and sensitive phenotypes of the B. cinerea isolates. The results of cross-resistance test showed no correlation between boscalid and carbendazim, procymidone, pyrimethanil, fluazinam or fluopyram. In this study, the succinate dehydrogenase gene B (sdhB), C (sdhC), and D (sdhD) were analyzed and compared in sensitive, low and moderately resistant B. cinerea isolates to boscalid. Results showed point mutations occurred simultaneously at sdhC amino acid positions 85 (G85A), 93 (I93V), 158 (M158V), and 168 (V168I) in 4 out of 10 sensitive isolates, 23 out of 26 low and 5 out of 5 moderately resistant B. cinerea isolates to boscalid. No point mutations were found in the sdhB and sdhD genes of all isolates. Furthermore, no point mutations were found in sdhB, sdhC and sdhD genes in 3 out of 26 low resistant B. cinerea isolates to boscalid. Therefore, we speculate the simultaneous point mutations in the sdhC gene may not be related to the resistance of B. cinerea to boscalid. These results suggested that there might be a substitution mechanism for the resistance of B. cinerea to the SDHI fungicide boscalid.

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