title: Antifungal and sprout regulatory bioactivities of phenylacetic acid, indole-3-acetic acid, and tyrosol isolated from the potato dry rot suppressive bacterium Enterobacter cloacae S11:T:07.
abstract: Enterobacter cloacae S11: T:07 (NRRL B-21050) is a promising biological control agent that has significantly reduced both fungal dry rot disease and sprouting in laboratory and pilot potato storages. The metabolites phenylacetic acid (PAA), indole-3-acetic acid (IAA), and tyrosol (TSL) were isolated from S11:T:07 liquid cultures provided with three different growth media. The bioactivities of these metabolites were investigated via thin-layer chromatography bioautography of antifungal activity, wounded potato assays of dry rot suppressiveness, and cored potato eye assays of sprout inhibition. Relative accumulations of PAA, IAA, and TSL in cultures were nutrient dependent. For the first time, IAA, TSL, and PAA were shown to have antifungal activity against the dry rot causative pathogen Gibberella pulicaris, and to suppress dry rot infection of wounded potatoes. Disease suppression was optimal when all three metabolites were applied in combination. Dosages of IAA that resulted in disease suppression also resulted in sprout inhibition. These results suggest the potential for designing culture production and formulation conditions to achieve a dual purpose biological control agent able to suppress both dry rot and sprouting of stored potatoes.
authors.affiliation: Crop Bioprotection Research Unit, United States Department of Agriculture, Agricultural Research Service, 1815 N. University Street, Peoria, IL, 61604, USA. slininpj@ncaur.usda.gov
authors.forename: P J
authors.initials: PJ
authors.lastname: Slininger
authors.forename: K D
authors.initials: KD
authors.lastname: Burkhead
authors.forename: D A
authors.initials: DA
authors.lastname: Schisler
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000494:pharmacology; D016972:Enterobacter cloacae / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology*; D010648:Phenylacetates / Q000494:pharmacology*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D011198:Solanum tuberosum / Q000382:microbiology*
chemical_list: D000935:Antifungal Agents; D007210:Indoleacetic Acids; D010648:Phenylacetates; C011867:4-hydroxyphenylethanol; C030737:indoleacetic acid; C025136:phenylacetic acid; D010626:Phenylethyl Alcohol