Resistance risk assessment for Fusarium graminearum to pydiflumetofen, a new succinate dehydrogenase inhibitor

Abstract

Background Pydiflumetofen is a new generation succinate dehydrogenase inhibitor currently undergoing the process of registration in China for the control of Fusarium head blight in wheat. A resistance risk assessment of Fusarium graminearum to pydiflumetofen was undertaken in this study. Results A total of 75 pydiflumetofen‐resistant mutants were generated through spontaneous selection and displayed high resistance with an average resistance factor (RF) value of 78. Four mutants were generated through UV mutagenesis and displayed very high resistance with an RF value >1000. The sequence analysis results for Sdh genes and fitness studies revealed the existence of four types of mutations. In particular, 32 spontaneous selection mutants (SP mutants) had an arginine (R) to histidine (H) transition at position 86 in FGSdhC, resulting in seriously reduced fitness. Seven SP mutants had an R to cysteine (C) transition at position 86 in FGSdhC, resulting in reduced fitness. Thirty‐six SP mutants had an alanine (A) to valine (V) transition at position 83 in FGSdhC and had no fitness penalties. The efficacy of pydiflumetofen towards a mutant carrying A83V in FGSdhC in vivo was significantly decreased at 42.7%. Four UV mutants had no mutations on all Sdh genes and no fitness penalties. Cross‐resistance among boscalid, fluopyram and pydiflumetofen was observed. Conclusion Sdhc mutations were found and other target site resistance may be present in laboratory PR mutants of F. graminearum. An overall moderate risk of resistance development in F. graminearum was recommended for pydiflumetofen. © 2019 Society of Chemical Industry

Tebuconazole resistance of Fusarium graminearum field populations from wheat in Henan Province

“…The moderate resistance risk of F. graminearum to pydiflumetofen has been reported (Sun et al., 2020). Since 1970, DMI fungicides, particularly tebuconazole, were used to control FHB in the flowering stage of wheat and achieved well preventive effect (Sun et al., 2020). It can not only reduce the occurrence of FHB, but also reduce the content of toxin in wheat grains (Xu, Ping, et al., 2018).…”

“…However, considering the shortage of high resistance varieties and the limitations of biological control, the chemical control has been the most popular strategy to avoid the occurrence of FHB for a long time. At present, growers usually spraying benzimidazole fungicides (carbendazim and thiophanate‐methyl), cyanoacrylate fungicide (phenamacril), succinate dehydrogenase inhibitor (SDHI) fungicide (pydiflumetofen) and sterol demethylation inhibitor (DMI) fungicides (tebuconazole and metconazole) against FHB in the flowering stage of wheat in China (Duan et al., 2018; Liu, Fu, et al., 2020; Liu, Liu, et al., 2020; Sun et al., 2020; Zhou & Wang, 2001). Since 1970, benzimidazole fungicides, particularly carbendazim, were used to control FHB, but F. graminearum strains resistant to carbendazim was found in the field in 1992 due to long‐term use (Liu et al., 2019; Zhou & Wang, 2001).…”

“…However, phenamacril is a high‐risk fungicide resistance for F. graminearum (Chen & Zhou, 2009; Li et al., 2006; Zhang et al., 2017). In recent years, a new SDHI fungicide pydiflumetofen with high activity against F. graminearum has been registered for control FHB (Sun et al., 2020). The moderate resistance risk of F. graminearum to pydiflumetofen has been reported (Sun et al., 2020).…”

“…In recent years, a new SDHI fungicide pydiflumetofen with high activity against F. graminearum has been registered for control FHB (Sun et al., 2020). The moderate resistance risk of F. graminearum to pydiflumetofen has been reported (Sun et al., 2020). Since 1970, DMI fungicides, particularly tebuconazole, were used to control FHB in the flowering stage of wheat and achieved well preventive effect (Sun et al., 2020).…”

The antioxidant methyl gallate inhibits fungal growth and deoxynivalenol production in Fusarium graminearum

“…Due to the lack of wheat cultivars highly resistant to FHB and DON (Jansen et al 2005), the application of systemic fungicides during the wheat flowering stage has been one of the primary tools for controlling disease and DON contamination in China (Chen et al 2019). Currently, fungicides including the sterol demethylation inhibitors tebuconazole and prothioconazole (Yin et al 2009), the novel myosin inhibitor phenamacril (Zhang et al, 2010(Zhang et al, , 2015 and the carboxamide fungicide pydiflumetofen (Chen et al 2020;Sun et al 2020) widely used in China are effective in controlling FHB and DON accumulation in wheat. However, due to extensive use, field Fusarium asiaticum strains with low tebuconazole resistance have been isolated, and some provinces of China have been reported to have moderate to high or high resistance risk for the fungicides phenamacril and pydiflumetofen (Chen et al 2020;Chen & Zhou 2009;Sun et al 2020).…”