Rhizonin, the First Mycotoxin Isolated from the Zygomycota, Is Not a Fungal Metabolite but Is Produced by Bacterial Endosymbionts

• DOI: 10.1128/aem.01784-06
• Publication Date: 2006-11-23T02:25:05Z
• Authors: Laila P. Partida-...; Carina Flores de ...; Keishi Ishida; Mie Ishida; Martin Roth; Katrin Buder; Christian Hertweck
• Keywords: Rhizopus; Sphingomonas

Rhizonin is a hepatotoxic cyclopeptide isolated from cultures of fungal Rhizopus microsporus strain that grew on moldy ground nuts in Mozambique. Reinvestigation this by series experiments unequivocally revealed "first mycotoxin lower fungi" actually not produced the fungus. PCR and phylogenetic studies based 16S rRNA gene sequences fungus associated with bacteria belonging to genus Burkholderia. By transmission electron microscopy, were localized within cytosol. Toxin production presence endosymbionts correlated curing an antibiotic, yielding nonproducing, symbiont-free phenotype. The final evidence for bacterial biogenesis toxin was obtained successful fermentation endosymbiotic pure culture isolation rhizonin A broth. This finding particular interest since related species are frequently used food preparations such as tempeh sufu.