Toxicity and genetic diversity of indoor and outdoor stachybotrys chartarum of different geographic origins

Thirty-one isolates of the genus Stachybotrys from indoor and outdoor environments were analyzed for presence of trichodiene synthase gene (Tri5), production of trichothecenes, boar sperm cell motility inhibition, and randomly amplified polymorphic DNA banding patterns (RAPDs). Stachybotrys chartarum isolates (n = 22) possessing the Tri5 gene (encodes the trichodiene synthase enzyme needed at the early steps of trichothecene synthesis) had similar RAPD fingerprints to each other, and 16 of these isolates contained satratoxins or trichodermol. Nine S. chartarum isolates, which were negative for Tri5 gene and trichothecenes, were less than 50% similar to the Tri5 positive group in RAPD fingerprints, but similar to each other. Nineteen of the isolates inhibited sperm motility at the level of EC₅₀ < 60 μg of crude extract mL^-1. Toxicity observed by inhibition of the boar spermatozoan motility was distributed among the two RAPD groups of S. chartarum.