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

Abstract

Fusarium graminearum is one of the phytopathogenic fungi causing cereal fusarium head blight worldwide. Flubeneteram (Flu) is a novel succinate dehydrogenase inhibitor (SDHI) which exhibits strong fungicidal activity against F. graminearum. In this study, four Flu-resistant (FluR) mutants were generated by fungicide domestication from the wildtype strain PH-1. Sequencing alignment results of FgSdh from PH-1 and FluR mutants showed that all the mutations could be categorized into three resistant genotypes. Genotype I had an A-to-T mutation at the −57 bp of the 5′ untranslated region (5′UTR) of FgSdhC 1 , while genotypes II and III carried nonsynonymous mutations conferring T77I or R86C in FgSdhC 2 , respectively. All the mutations conferring the Flu resistance and causing fitness penalty were validated. The genotype I mutant showed high Flu-resistance, while genotype II and III mutants exhibited low Flu resistance. Additionally, all the FluR genotypes showed distinct cross-resistance patterns among the five SDHIs.

Sterol 14α-Demethylase CaCYP51A and CaCYP51B are Functionally Redundant, but Differentially Regulated in Colletotrichum acutatum: Responsibility for DMI-Fungicide Resistance

“…acutatum isolates YC20 and YC24 were selected arbitrarily to generate the Teb R mutants from mycelia and conidia by in vitro repeated exposure to Teb. For mycelium-originated mutagenesis, 1000 mycelial plugs of Teb S isolates were transferred onto the PDA medium amended with Teb at its minimum inhibitory concentration (MIC = 5 μg/mL). After incubation at 25 °C in darkness for 20–30 days, the fast-growing sectors were transferred to the PDA medium containing 5 μg/mL Teb for resistance identification.…”

Comprehensive Overview of Carboxamide Derivatives as Succinate Dehydrogenase Inhibitors

“…Therefore, SDHIs are excellent candidates for overcoming fungicide resistance and improving plant disease control. However, according to the results from the Fungicide Resistance Action Committee (FRAC), many plant pathogens have developed resistance toward existing SDHIs fungicides due to their long-term abuse and high usage rate. − …”

Reversible Regulation of Succinate Dehydrogenase by Tools of Photopharmacology

“…It was reported that there was no cross-resistance of SDHIs with different structures. 16 Moreover, modulation of SDH had been reported to be utilized as a promising therapeutic target 3 to SDH mutations. A review was published with discussions of the SDH regulations in expression and activity, 17 indicating the farreaching significance of SDH regulations.…”

“…The fragment recombination strategy, the carbon–silicon switch strategy, and a computational substitution optimization method were applied in the quest of new SDHI fungicides. It was reported that there was no cross-resistance of SDHIs with different structures . Moreover, modulation of SDH had been reported to be utilized as a promising therapeutic target to SDH mutations.…”