title: Biotransformation of the Streptomyces scabies phytotoxin thaxtomin A by the fungus Aspergillus niger.
abstract: Of several hundred microorganisms randomly selected from the environment, only a fungal isolate identified as Aspergillus niger van Tiegham var. niger was found to transform the phytotoxin thaxtomin A to much less toxic metabolites. The rate and extent of transformation of thaxtomin A was tested under a variety of conditions, including different growth media, biomass concentrations, incubation periods, and shaker speeds. Under optimum conditions the fungus converted thaxtomin A into two major and five minor metabolites. The two major metabolites and three of the five minor metabolites were fully characterized by a combination of mass spectral and nuclear magnetic resonance techniques. When assayed on aseptically produced mini-tubers, the major metabolites proved to be much less phytotoxic than thaxtomin A.
authors.affiliation: Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, 1391 Sanford Street, London, Ontario N5V 4T3, Canada. Lazarovitsg@agr.gc.ca
authors.forename: George
authors.initials: G
authors.lastname: Lazarovits
authors.forename: Jackie
authors.initials: J
authors.lastname: Hill
authors.forename: Russell R
authors.initials: RR
authors.lastname: King
authors.forename: Larry A
authors.initials: LA
authors.lastname: Calhoun
mesh_terms: D001234:Aspergillus niger / Q000378:metabolism*; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D018533:Biomass; D001711:Biotransformation; D003470:Culture Media / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010879:Piperazines / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D013997:Time Factors
chemical_list: D001427:Bacterial Toxins; D003470:Culture Media; D007211:Indoles; D010879:Piperazines; C406691:thaxtomine A