First Report of the Production of Mycotoxins and Other Secondary Metabolites by Macrophomina phaseolina (Tassi) Goid. Isolates from Soybeans (Glycine max L.) Symptomatic with Charcoal Rot Disease

Macrophomina phaseolina (Tassi) Goid., the causal agent of charcoal rot disease of soybean, is capable of causing disease in more than 500 other commercially important plants. This fungus produces several secondary metabolites in culture, including (-)-botryodiplodin, phaseolinone and mellein. Given that independent fungal isolates may differ in mycotoxin and secondary metabolite production, we examined a collection of 89 independent M. phaseolina isolates from soybean plants with charcoal rot disease using LC-MS/MS analysis of culture filtrates. In addition to (-)-botryodiplodin and mellein, four previously unreported metabolites were observed in >19% of cultures, including kojic acid (84.3% of cultures at 0.57-79.9 mu g/L), moniliformin (61.8% of cultures at 0.011-12.9 mu g/L), orsellinic acid (49.4% of cultures at 5.71-1960 mu g/L) and cyclo[L-proline-L-tyrosine] (19.1% of cultures at 0.012-0.082 mu g/L). In addition, nine previously unreported metabolites were observed at a substantially lower frequency (