Functional characterization of MoSdhB in conferring resistance to pydiflumetofen in blast fungus Magnaporthe oryzae

Abstract

BACKGROUND: Rice (Oryza sativa) is an important cereal crop around the world, and has constantly been threaten by the most destructive fungus Magnaporthe oryzae. Pydiflumetofen, a novel succinate dehydrogenase inhibitor (SDHI), is currently being used for controlling various fungal diseases. However, the potential resistance risk of M. oryzae to pydiflumetofen has remained unclear to date, and finding the resistance mechanism is critical for the usage of this fungicide.RESULTS: The M. oryzae strain Guy11 is sensitive to pydiflumetofen, with EC 50 value of 1.24 ∼g mL −1 . 58 pydiflumetofenresistant (PR) mutants were obtained through pydiflumetofen-induced spontaneous mutation, with a mean EC 50 value >500 ∼g mL −1 , and the resistance factor (RF) >400. The PR mutants displayed positive cross-resistance to carboxin, but were more sensitive to fluopyram. Sequencing analysis showed that all PR mutants presented a cytosine-to-thymine transition at nucleotide position +1218, resulting in a replacement of histidine 245 by tyrosine (H245Y) on MoSdhB. The mutation of MoSdhB exhibited strong resistant phenotype, but no detectable growth deficits in fungal development, including vegetative growth and pathogenicity of M. oryzae. An allele-specific PCR for rapid detection of the H245Y mutants was established in M. oryzae.CONCLUSION: The M. oryzae is sensitive to pydiflumetofen, and shows a medium to high resistance risk to pydiflumetofen. A point mutation of MoSdhB (H245Y) is responsible for the fungal resistance to pydiflumetofen in M. oryzae.

Effects of Flubeneteram on Inhibiting the Development of Puccinia striiformis f. sp. tritici in Wheat Leaves

“…SDHIs, targeting the succinate dehydrogenase complex, have gradually become the third largest group of fungicides in the world after QoIs and ergosterol biosynthesis inhibitors (EBIs). 30 Flubeneteram is a new fungicide targeting SDH that was successfully developed using the PFVS method. 23 Previous studies have shown that flubeneteram has a control effect on rice sheath blight.…”

Functional Differentiation of the Succinate Dehydrogenase Subunit SdhC Governs the Sensitivity to SDHI Fungicides, ROS Homeostasis, and Pathogenicity in Fusarium asiaticum

“…To date, pydiflumetofen (PYD), a novel succinate dehydrogenase inhibitor, is the only SDHI fungicide registered for controlling wheat FHB with excellent efficacy in the field. , However, the PYD resistance was reported in another phytopathogenic fungi, including F. graminearum, Fusarium pseudograminearum, Fusarium fujikuroi, Botrytis cinerea, Magnaporthe oryzae, and Didymella bryoniae. − Our previous study showed that SdhB H248Y , SdhC 1 A64V , or SdhC 1 R67K mutations are responsible for the resistance to PYD in F. asiaticum .…”

Study on Mechanisms of Resistance to SDHI Fungicide Pydiflumetofen in Fusarium fujikuroi

“…The succinate dehydrogenase (SDH) complex is composed of four protein subunits (SdhA, SdhB, SdhC, and SdhD) involved in the regulation of the respiratory chain and TCA cycle. − The flavonoid proteins SdhA and iron–sulfur SdhB are exposed to the mitochondrial matrix, while two other hydrophobic proteins (SdhC and SdhD) bind to SdhAB dimers on the mitochondrial inner membrane to anchor complex II. − SDHI fungicides specifically interfere with respiration by blocking the SDH ubiquinone (UQ) binding site formed by the highly conserved SdhB, SdhC, and SdhD residues . Recently, amino acid alterations in SdhB, SdhC, and SdhD causing resistance to SDHI have been reported. ,− The Fungicide Resistance Action Committee (FRAC) considers SDHI at medium to high risk for resistance development () . However, there are no data on the risk of resistance of F. fujikuroi to Pyd.…”