Mycoactive acetate esters from apple fruit stimulate adhesion and germination of conidia of the gray mold fungus.
Ethyl acetate, 2-methylbutyl acetate, butyl acetate (BA), and hexyl acetate were detected by solid-phase microextraction and gas-liquid chromatography inside slices of Golden Delicious apple and in water droplets on the skin of slices incubated in sealed glass jars. Conidial adhesion and germination of the gray mold fungus, Botrytis cinerea, was assessed on apple slices after exposure or no exposure to the esters in the headspaces of glass jars. Attached conidia were dislodged by sonication and remaining conidia on apple slices were counted by microscopy. Adhesion generally increased as BA increased to 7.2 microg mL(-1), but declined with greater concentrations. BA at 0-3.6 microg mL(-1) for 24 h stimulated adhesion 2-fold greater compared to that at 4 h. Adhesion stimulated by BA increased as a function of time (0-24 h), showing linear trends (r (2) = 0.99; p = 0.01) during 0-12 h. The four esters were similar in their ability to stimulate adhesion. Germination of conidia exposed to BA increased linearly (r (2) = 0.95-0.98; p = 0.01) during 4-12 h. Conidial adhesion stimulated by BA preceded conidial germination by 2 h. The four esters stimulated conidial germination to similar levels. Results indicated that acetate esters formed in apple fruit are mycoactive, influencing life-cycle events of B. cinerea important to its survival on the fruit. The similar responses of three B. cinerea isolates to four acetate esters suggests a common stimulation mechanism may operate in B. cinerea.
Filonow
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AB
Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, Oklahoma 74078, USA. alexfil@okstate.edu
D000085:Acetates / Q000032:analysis*; D020171:Botrytis / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D002448:Cell Adhesion; D004952:Esters / Q000032:analysis*; D005638:Fruit / Q000737:chemistry* / Q000382:microbiology*; D027845:Malus / Q000737:chemistry*; D013172:Spores, Fungal / Q000502:physiology
D000085:Acetates; D004952:Esters; C006848:butyl acetate; C007650:ethyl acetate