Mechanistic Insights into Stereospecific Bioactivity and Dissipation of Chiral Fungicide Triticonazole in Agricultural Management

Abstract

Research interest in chiral pesticides has increased probably because enantiomers often exhibit different environmental fate and toxicity. An investigation into the enantiomer-specific bioactivity of chiral triticonazole enantiomers in agricultural systems revealed intriguing experimental and theoretical evidence. For nine of the phytopathogens studied ( Rhizoctonia solani, Fusarium verticillioide, Botrytis cinerea (strawberry and tomato), Rhizoctonia cereali, Alternaria solani, Gibberella zeae, Sclerotinia sclerotiorum, and Pyricularia grisea), the fungicidal activity data showed ( R)-triticonazole was 3.11-82.89 times more potent than the ( S) enantiomer. Furthermore, ( R)-triticonazole inhibited ergosterol biosynthesis and cell membrane synthesis 1.80-7.34 times higher than its antipode. Homology modeling and molecular docking studies suggested the distinct bioactivities of the enantiomers of triticonazole were probably due to their different binding modes and affinities to CYP51b. However, field studies demonstrated that ( S)-triticonazole was more persistent than ( R)-triticonazole in fruits and vegetables. The results showed that application of pure ( R)-triticonazole, with its high bioactivity and relatively low resistance risk, instead of the racemate in agricultural management would reduce the application dosage required to eliminate carcinogenic mycotoxins and any environmental risks associated with this fungicide, yielding benefits in food safety and environmental protection.

Enantioselectivity in degradation and ecological risk of the chiral pesticide ethiprole

“…The supernatant acetonitrile (25 ml) was collected and completely evaporated. The clean‐up method of these soil extracts was performed according to an existing research protocol using a Florisil solid phase extraction column (Q. Zhang et al, ; Q. Zhang, Zhang, et al, ). The ethiprole residue was then redissolved in 1 ml of methanol and water solution (65:35, v/v).…”

Mechanistic Insights into Stereospecific Antifungal Activity of Chiral Fungicide Prothioconazole against Fusarium oxysporum F. sp. cubense

“…Significant stereoselective differences between Pro enantiomers were found in their environmental behaviors and toxicological effects. R-Pro is preferentially degraded in soils, and S-Pro is preferentially accumulated in earthworm (Eisenia foetida) [19,20]. Remarkable stereoselective endocrine-disrupting effects of Pro were found with the S-Pro, showing more potency than its R-enantiomers [21].…”

Stereoselective bioactivity, toxicity and degradation of the chiral triazole fungicide bitertanol

“…The four stereoisomers concentrations were the EC 10 , EC 50 , and EC 90 values that were obtained from the 2.2 section. Ergosterol was extracted and determined according to prior references . The mycelia were collected by filtration and washed with sterile water, and the mycelia were dried in a vacuum freeze, then the dried mycelia were grinded in liquid nitrogen.…”

“…Ergosterol was extracted and determined according to prior references. [15][16][17] The mycelia were collected by filtration and washed with sterile water, and the mycelia were dried in a vacuum freeze, then the dried mycelia were grinded in liquid nitrogen. Next, 0.15 g of mycelia was added into a 50 mL centrifuge tube with 10 mL methanol-chloroform (3:1 V/V) and the solution was allowed to stand for 12 h at 60 ∘ C. A mixture of 10 mL of distilled water, chloroform, and phosphoric acid buffer containing KCl was added; subsequently, the chloroform solution was transferred to another tube and flushed with nitrogen until dry.…”