posted on 2018-06-26, 00:00authored byQing Zhang, Zhaoxian Zhang, Bowen Tang, Beibei Gao, Mingming Tian, Edmond Sanganyado, Haiyan Shi, Minghua Wang
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.