Resistance risk assessment for benzovindiflupyr in Sclerotium rolfsii and transmission of resistance genes among population

Abstract

BACKGROUNDSclerotium rolfsii is a destructive soil‐borne fungal pathogen which is distributed worldwide. In previous study, the succinate dehydrogenase inhibitor (SDHI) fungicide benzovindiflupyr has been identified for its great antifungal activity against S. rolfsii. This study is aimed to investigate the resistance risk and mechanism of benzovindiflupyr in S. rolfsii.RESULTSEight stable benzovindiflupyr‐resistant isolates were generated by fungicide adaptation. Although the obtained 8 resistant isolates have a stronger pathogenicity than the parental sensitive isolate, they have a fitness penalty in the mycelial growth and sclerotia formation compared to the parental isolate. A positive cross‐resistance existed in the resistant isolates between benzovindiflupyr and thifluzamide, carboxin, boscalid and isopyrazam. Three point mutations, including SdhBN180D, SdhCQ68E and SdhDH103Y, were identified in the benzovindiflupyr‐resistant isolates. However, molecular docking analysis indicated that only SdhDH103Y could influence the sensitivity of S. rolfsii to benzovindiflupyr. After mycelial co‐incubation of resistant isolates and the sensitive isolate, resistance genes may be transmitted to the sensitive isolate. The in vivo efficacy of benzovindiflupyr and thifluzamide against benzovindiflupyr‐resistant isolates was a little lower than that against the sensitive isolate but with no significant difference.CONCLUSIONAbove results suggested a low to medium resistance risk of S. rolfsii to benzovindiflupyr. However, once resistance occurs, it is possible to spread in the population of S. rolfsii. This study is helpful to understanding the risk and mechanism of resistance to benzovindiflupyr in multinucleate pathogens such as S. rolfsii.This article is protected by copyright. All rights reserved.

Antifungal Activity and Mechanism of Physcion against Sclerotium rolfsii, the Causal Agent of Peanut Southern Blight

“…The succinate dehydrogenase inhibitor fungicide thifluzamide has historically been employed for the management of PSB fungi, although resistance to it has emerged in S. rolfsii . Additionally, the triazole fungicides prothioconazole and tebuconazole have been used for controlling PSB .…”

“…The succinate dehydrogenase inhibitor fungicide thifluzamide has historically been employed for the management of PSB fungi, although resistance to it has emerged in S. rolfsii. 6 Additionally, the triazole fungicides prothioconazole and tebuconazole have been used for controlling PSB. 7 Due to the extensive usage of triazole fungicides and shifts in climate patterns, instances of tebuconazole-resistant strains have been documented in China.…”