title: Bioprospecting for secondary metabolites in the entomopathogenic bacterium Photorhabdus luminescens subsp. sonorensis.
abstract: Crude extracts of in vitro and in vivo cultures of two strains of Photorhabdus l. sonorensis (Enterobacteriaceae) were analyzed by TLC, HPLC-UV and LC-MS. Nine unique compounds with mass/charge ratios (m/z) ranging from 331.3 to 713.5 were found in MS analyses. Bioactivity of extracts was assessed on a selection of plant pathogens/pests and non-target species. Caborca strain extracts showed the highest activity against Helicoverpa zea (Lepidoptera: Noctuidae) neonates at all concentrations tested. Mortality ranged from 11% (at 10μg/ml) to 37% (at 40μg/ml). Strain CH35 extracts showed the highest nematicidal activity on Meloidogyne incognita (Tylenchida: Meloidogynidae) at 40μg/ml. Low to no nematicidal activity was observed against the non-target species Steinernema carpocapsae (Rhabditida: Steinernematidae) and Caenorhabditis elegans (Rhabditida: Rhabditidae). Caborca extracts exhibited a strong antibiotic effect on Pseudomonas syringae (Pseudomonadales: Pseudomonadacedae) at 40μg/ml, while both Caborca and CH35 extracts inhibited the growth of Bacillus subitillis (Bacillales: Bacillaceae) at 40μg/ml. All extracts strongly inhibited the growth of the fungus Fusarium oxysporum (Hypocreales: Nectriceae) but not that of Alternaria alternata (Pleosporales: Pleosporaceae). Contrastingly, a moderate to high inhibitory effect was denoted on the non-target biocontrol fungus Beauveria bassiana (Hypocreales: Clavivipitaceae).
authors.affiliation: Department of Entomology, University of Arizona, 1140 E. South Campus Dr., Tucson, AZ 85721-0036, United States.
authors.forename: Rousel A
authors.initials: RA
authors.lastname: Orozco
authors.affiliation: Natural Products Center, University of Arizona, 250 E. Valencia Road, Tucson, AZ 85706, United States.
authors.forename: István
authors.initials: I
authors.lastname: Molnár
authors.affiliation: Institut für Molekulare Biowissenschaften, Goethe Universität, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany.
authors.forename: Helge
authors.initials: H
authors.lastname: Bode
authors.affiliation: Department of Entomology, University of Arizona, 1140 E. South Campus Dr., Tucson, AZ 85721-0036, United States. Electronic address: spstock@email.arizona.edu.
authors.forename: S Patricia
authors.initials: SP
authors.lastname: Stock
mesh_terms: D000818:Animals; D065132:Bioprospecting / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D002855:Chromatography, Thin Layer; D045424:Complex Mixtures / Q000494:pharmacology*; D013058:Mass Spectrometry; D010572:Pest Control, Biological / Q000379:methods*; D020637:Photorhabdus / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D045424:Complex Mixtures
keywords: Bioactivity; Crude extracts; Photorhabdus; Plant-pathogens; Secondary metabolites