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Fluopyram, as a novel succinate dehydrogenase inhibitors (SDHIs) fungicide, was applied for controlling grey mould in China. In order to investigate the possible development of resistance development of Botrytis cinerea to fluopyram, Botrytis cinerea were collected from eight areas in Liaoning Province, and the sensitivities of these isolates were assessed by mycelium growth and the fitness and resistance mechanism of resistant isolates screened. The results showed that the sensitivity baseline of B. cinerea to fluopyram was (4.82 ± 1.49) μg/mL, and 5 low resistance isolates to fluopyram were detected. The fitness of resistant isolates showed a downward trend of several variables, such as mycelium growth, mycelium dry weight, sporulation and lesion diameter, which were significantly lower than those of sensitive isolates. Conidia germination did not differ significantly between sensitive and resistant isolates. There was no cross‐resistance between fluopyram and fludioxonil/boscalid/pyrimethanil/procymidone/carbendazim. The succinate dehydrogenase activity of resistant isolates was higher than that of sensitive isolates with fluopyram or not, and the inhibition of fluopyram on succinate dehydrogenase of sensitive isolates was greater than that of resistant isolates. Resistant isolates AS8 and AS14 carried the point mutation (N230I) in subunit B. These results provided that fluopyram belonged to a medium‐high resistance risk to B. cinerea. Information for managing resistance suggested that (1) the number of fluopyram applications should be limited to one per season and (2) fluopyram could be a valid alternative to fludioxonil, pyrimethanil, procymidone and carbendazim for the control of grey mould of tomato. [ABSTRACT FROM AUTHOR]

The new insecticide broflanilide, which possesses high insecticidal activity against agricultural pests, acts on the γ-aminobutyric acid receptor in the insect nervous system. At present, few studies assessed its effect on the nervous system of zebrafish, especially its sub-chronic toxicity on the zebrafish brain. In this study, the sub-chronic toxicity of broflanilide on the zebrafish brain was assessed. After 21 days of exposure at 36.3 μg/L, broflanilide caused oxidative damage to the zebrafish brain, increased the levels of reactive oxygen species and malondialdehyde, and inhibited the activities of superoxide dismutase, catalase, and glutathione peroxidase. Overall, these changes result in brain cell apoptosis, and inhibited growth and development. Moreover, broflanilide affects the release of acetylcholinesterase, γ-aminobutyric acid, 5-hydroxy tryptamine, and dopamine as well as the expression of related genes in the brain, leading to abnormal zebrafish behaviour. These results corroborate the sub-chronic toxicity of broflanilide on zebrafish brain, which helps the further understanding of the potential environmental risk of broflanilide. [ABSTRACT FROM AUTHOR]

BACKGROUND: Plant disease is one of the most serious problems in agriculture that can damage crops. Chemical fungicides are widely used to control plant diseases, but have led to resistance and a series of environmental problems. It is, therefore, necessary to develop highly effective and eco‐friendly antimicrobial compounds with novel structures. RESULTS: A series of novel hydantoin cyclohexyl sulfonamide derivatives were synthesized through an intramolecular condensation reaction. The bioassay results indicated that a majority of the title compounds displayed potent inhibitory activity against Botrytis cinerea, Sclerotinia sclerotiorum and Erwinia carotorora. The in vivo inhibition rate of compound 3h was 91.01% against B. cinerea, which was higher than that of iprodione (84.07%). Compound 3w showed excellent antifungal activity against B. cinerea with a half‐maximal effective concentration (EC50) of 4.80 μg ml–1, which is lower than that of iprodione. Compound 3q had an EC50 value of 1.44 μg ml–1 against S. sclerotiorum, which was close to that of iprodione (1.39 μg ml–1), and the inhibition rate was also similar to that of iprodione. Compounds 3i and 3w had the best inhibition efficacy against S. sclerotiorum, both on growth of the mycelium and sclerotia and in the greenhouse pot test in vitro. Further study showed that compounds 3h, 3r and 3s have superb antibacterial activity against E. carotorora with EC50 values of 2.65, 4.24 and 4.29 μg ml–1 respectively, and were superior to streptomycin sulfate (5.96 μg ml–1). CONCLUSION: Because of their excellent antifungal and antibacterial activity against B. cinerea, S. sclerotiorum and E. carotorora, these hydantoin cyclohexyl sulfonamide derivatives could be considered as suitable candidates for new antimicrobial agents. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The optimization of fermentation conditions is necessary for field application of biological control agents. The present study was designed to optimize the fermentation conditions for the Bacillus aerius strain, JS-786 in terms of cell dry mass and its antifungal activity against Botrytis cinerea with response surface methodology. A strain of bacteria with strong antifungal activity was isolated from the phyllosphere of tomato plant and identified as B. aerius JS-786 based on the sequence homology of its 16S rRNA gene. After the success of preliminary antifungal activity tests, response surface methodology was used to optimize the fermentation conditions (medium pH, gelatin percentage, incubation period, rotatory speed and incubation temperature) to maximize the cell dry mass and antifungal activity against B. cinerea. A 25 factorial central composite design was employed and multiple response optimization was used to determine the desirability of the operation. The results of regression analysis showed that at the individual level, all of the experimental parameters were significant for cell dry mass; significant results were obtained for antifungal activity pH, incubation period, rotatory speed and incubation temperature. The interactive effect of the incubation period, rotatory speed and incubation temperature was significant. Maximum cell dry mass (8.7 g/L) and inhibition zone (30.4 mm) were obtained at pH 6.4, gelatin 3.2%, incubation period 36.92 h, rotatory speed 163 rpm and temperature 33.5°C. This study should help to formulate a more rational and cost-effective biological product both in terms of bacterial growth and antifungal activity. [ABSTRACT FROM AUTHOR]

In recent years, Botrytis cinerea has led to serious yield losses because of its resistance to fungicides. Many sulfonamides with improved properties have been used. (1S,2R-((3-bromophenethyl)amino)-N-(4-chloro-2-trifluoromethylphenyl)cyclohexane-1-sulfonamide) (abbreviation: SYAUP-CN-26) is a new sulfonamide compound that has excellent activity against B. cinerea. This study investigated the effect of SYAUP-CN-26 on electric conductivity, nucleic acids leakage, malondialdehyde (MDA) content, and reducing sugars and membrane structure reduction of B. cinerea. The results showed that the cell membrane permeability of B. cinerea increased with increasing concentrations of SYAUP-CN-26; meanwhile, the sugar content decreased, the malondialdehyde content increased, and relative electric conductivity and nucleic acid substance leakage were observed in the cell after exposure to 19.263 mg/L SYAUP-CN-26 for 24 h. After 48 h of exposure to 1.823 mg/L and 19.263 mg/L SYAUP-CN-26, the cell membranes of B. cinerea mycelia were observed to be damaged under propidium iodide (PI) and transmission electron microscopy (TEM) observations. It is assumed that SYAUP-CN-26 was responsible for the damage of cell membrane. Overall, the results indicate that SYAUP-CN-26 could inhibit the growth of B. cinerea cells by damaging the cell membranes. [ABSTRACT FROM AUTHOR]

In order to explore more efficient sulfonamides against Botrytis cinereal, 36 novel cyclohexylsulfonamides were synthesized by N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDCI) and 1-hydroxybenzotriazole (HOBt) condensation reaction using chesulfamide as a lead compound, introducing thiazole and pyrazole active groups. Their structures were characterized by 1H-NMR, 13C-NMR, mass spectrum (MS), and elemental analysis. Compound III -31 was further confirmed by X-ray single crystal diffraction. The in vitro and in vivo fungicidal activities against B. cinerea were evaluated by three bioassay methods. The results of mycelial growth demonstrated that median effective concentration (EC50) values of nine compounds were close to boscalid (EC50 = 1.72 µg/mL) and procymidone (EC50 = 1.79 µg/mL) against B. cinerea (KZ-9). In the spore germination experiment, it was found that compounds III-19 and III-31 inhibited germination 93.89 and 98.00%, respectively; at 10 µg/mL, they approached boscalid (95.97%). In the tomato pot experiment, the control effects of two compounds (III-21 and III-27) were 89.80 and 87.90%, respectively, at 200 µg/mL which were significantly higher than boscalid (81.99%). The structure–activity relationship (SAR) was also discussed, which provided a valuable idea for developing new fungicides. [ABSTRACT FROM AUTHOR]

In recent years, Botrytis cinerea has led to serious yield losses because of its resistance to fungicides. Many sulfonamides with improved properties have been used. (1 S, 2 R -((3-bromophenethyl)amino)- N -(4-chloro-2-trifluoromethylphenyl)cyclohexane-1-sulfonamide) (abbreviation: SYAUP-CN-26) is a new sulfonamide compound that has excellent activity against B . cinerea . This study investigated the effect of SYAUP-CN-26 on electric conductivity, nucleic acids leakage, malondialdehyde (MDA) content, and reducing sugars and membrane structure reduction of B. cinerea . The results showed that the cell membrane permeability of B. cinerea increased with increasing concentrations of SYAUP-CN-26; meanwhile, the sugar content decreased, the malondialdehyde content increased, and relative electric conductivity and nucleic acid substance leakage were observed in the cell after exposure to 19.263 mg/L SYAUP-CN-26 for 24 h. After 48 h of exposure to 1.823 mg/L and 19.263 mg/L SYAUP-CN-26, the cell membranes of B. cinerea mycelia were observed to be damaged under propidium iodide (PI) and transmission electron microscopy (TEM) observations. It is assumed that SYAUP-CN-26 was responsible for the damage of cell membrane. Overall, the results indicate that SYAUP-CN-26 could inhibit the growth of B. cinerea cells by damaging the cell membranes., Competing Interests: The authors declare no conflicts of interest.