Truncated satratoxin gene clusters in selected isolates of the atranone chemotype of Stachybotrys chartarum (Ehrenb.) S. Hughes

Abstract

The fungus Stachybotrys (S.) chartarum was isolated from culinary herbs, damp building materials, and improperly stored animal forage. Two distinct chemotypes of the fungus were described that produced either high-cytotoxic macrocyclic trichothecenes (S type) or low-cytotoxic atranones (A type). Recently, two distinct gene clusters were described that were found to be necessary for the biosynthesis of either macrocyclic trichothecenes (21 SAT (Satratoxin) genes) or atranones (14 ATR (Atranone) genes). In the current study, PCR primers were designed to detect SAT and ATR genes in 19 S. chartarum chemotype S and eight S. chartarum chemotype A strains. Our analysis revealed the existence of three different genotypes: satratoxin-producing strains that harbored all SAT genes but lacked the ATR gene cluster (genotype S), non-satratoxin-producing strains that possessed the ATR genes but lacked SAT genes (genotype A), and a hitherto undescribed hybrid genotype among non-satratoxin-producing strains that harbored all ATR genes and an incomplete set of SAT genes (genotype H). In order to improve the discrimination of genotypes, a triplex PCR assay was developed and applied for the analysis of S. chartarum and S. chlorohalonata cultures. The results show that genes for macrocyclic trichothecenes and atranones are not mutually exclusive in S. chartarum. Correlation of the new genotype-based concept with mycotoxin production data shows also that macrocyclic trichothecenes are exclusively produced by S. chartarum genotype S strains.

Toxin Production by Stachybotrys chartarum Genotype S on Different Culture Media

“…from straw, IBT40293 from building materials [ 32 ] and ATCC34916 from oats. These strains were initially characterized using previously described molecular and mass spectrometric methods [ 7 , 32 , 33 ] and were confirmed as S. chartarum genotype S. For long-term preservation, fungal cultures were treated as described by Niessen and Vogel [ 34 ] and maintained at −80 °C. Working cultures of Stachybotrys spp.…”

“…Stachybotrys (S.) chartarum is the most frequently isolated species of the genus Stachybotrys [ 1 , 2 ] and had been isolated from dead plant materials (e.g., herbs, straw, and hay) and other cellulosic, and water damaged substrates (e.g., wallpaper, plasterboard, or wooden lining) [ 3 , 4 , 5 , 6 ]. The species S. chartarum can be further subdivided into three genotypes, the highly cytotoxic genotype S that produces macrocyclic trichothecenes (MCT), the low cytotoxic genotype A that produces atranone and the recently described genotype H that produces phenylspirodrimanes, but no macrocyclic trichothecenes [ 7 ].…”

Posters

“…Subsequently, two steps were simulated: (i) during the co-incubation conidia can become adherent or phagocytosed with certain probabilities and (ii) during the washing step non-associated conidia are removed with the respective probability. To estimate these microscopic parameters, we performed a grid-based screening and com- PI-13 | Characterization of Candida albicans transcriptional and metabolic profiles upon exposure to distinct hypha-inducing stimuli F. Gerwien 1,2,3 ; E. Garbe 1,2,3 ; B. Böttcher 1,2,3 Results: The MICs varied between 0,5 -1 μg/ml for amorolfine and ciclopirox and between 2 -8μ g/ml for terbinafine. Distinctly more combinations of subinhibitory concentrations between amorolfine and terbinafine than between ciclopirox and terbinafine induced a 100% growth inhibition.…”

“…Objectives: In order to improve the discrimination of genotypes, a triplex PCR assay was developed and applied for the analysis of S. chartarum cultures [3]. Results: Our analysis revealed the existence of three different genotypes: satratoxin-producing strains that harbored all SAT genes but lacked the ATR gene cluster (genotype S), non-satratoxin-producing strains that possessed the ATR genes but lacked SAT genes (genotype A), and a hitherto undescribed hybrid genotype among nonsatratoxin-and putatively atranone-producing strains that harbored all ATR genes and an incomplete set of SAT genes (genotype H).…”

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