Effects of fungal and plant esterases on the fungicidal activity of nitrophenyl esters

摘要

AbstractAryl esterases, present within leaves and fungal spores and on their surfaces, hydrolysed 2‐naphthyl, 4‐nitrophenyl and 4‐(1‐substituted alkyl)‐2, 6‐dinitrophenyl esters at rates which appeared to be determined by the nature of the ester group and by the alkyl substituents in the molecule. No simple relationship was found between partitioning (as measured by Rm values from reverse‐phase t.l.c.) and susceptibility to hydrolysis by esterases. The most readily hydrolysed alkyldinitrophenyl esters are not those derived from parent nitrophenols with the greatest fungitoxicity in vivo or in vitro and the highly active 4‐(1‐cyclobutylalkyl)‐2, 6‐dinitrophenyl crotonates are amongst the least easily hydrolysed. It is suggested that alkyldinitrophenyl esters may have their own mode of action as powdery mildew fungicides which complements, and may even supplant, that resulting from hydrolysis to the parent alkyldinitrophenol. The proposed mechanism is disruption of the fungal cell membrane (as a result of surfactant properties) leading to leakage of esse