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

• DOI: 10.1021/acs.jafc.3c03678
• Publication Date: 2023-09-20T16:58:35Z
• Authors: Yu Liu; Yang Sun; Yang Bai; Xin Cheng; Hui Li; Xing Chen; Yu Chen

Rice bakaenii disease (RBD) is a widespread and devastating mainly caused by Fusarium fujikuroi. Pydiflumetofen (Pyd) novel succinate dehydrogenase inhibitor (SDHI) with strong inhibitory activity against F. fujikuroi, but the mechanism of resistance to Pyd has not been well studied for this pathogen. Through fungicide adaption, total 12 Pyd-resistant mutants were obtained level could be divided into three categories high (HR), moderate (MR), low (LR) factors (RF) 184.04–672.90, 12.63–42.49, <10, respectively. Seven genotypes point mutations in FfSdh genes (FfSdhBH248L, FfSdhBH248D, FfSdhBH248Y, FfSdhC2A83V, FfSdhC2H144Y, FfSdhDS106F, FfSdhDE166K) found these mutants, among which genotype FfSdhBH248L FfSdhC2A83V showed HR, FfSdhDE166K MR, FfSdhDS106F LR. Moreover, all substitutions amino acid including FfSdhBH248L/D/Y, FfSdhC2A83V,H144Y, FfSdhDS106F,E166K conferring fujikuroi verified protoplast transformation. Additionally, positive cross-resistance was detected between another SDHI penflufen, while no phenamacril, prochloraz, azoxystrobin, carbendazim, or fludioxonil. Although pathogenicity increased compared that wild-type parental strains, mycelial growth rate spore production levels resistant significantly decreased (P < 0.05), indicating significant fitness cost Taken together, risk might moderate, appropriate precautions development natural populations should taken account when used control RBD.