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A mycoparasite, Scytalidium parasiticum sp. nov., isolated from the basidiomata of Ganoderma boninense causing basal stem rot of oil palm in Johor, Malaysia, is described and illustrated. It is distinct from other Scytalidium species in having smaller asci and ascospores (teleomorphic stage), longer arthroconidia (anamorphic stage), hyaline to yellowish chlamydospores, and producing a fluorescent pigment. The phylogenetic position of S. parasiticum was determined by sequence analyses of the internal transcribed spacers and the small-subunit ribosomal RNA gene regions. A key to identify Scytalidium species with teleomorphic stage is provided. [ABSTRACT FROM AUTHOR]

Fusarium spp. are economically important crop pathogens and causal agents of Fusarium head blight (FHB) of cereals worldwide. Of the FHB pathogens, Fusarium graminearum 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON) are the most aggressive mycotoxigenic chemotypes, threatening food and feed quality as well as animal and human health. The objective of the study was to evaluate host specificity and fungal-fungal interactions of Sphaerodes mycoparasitica- a recently described mycoparasite - with F. graminearum 3- and 15-ADON strains by employing in vitro, microscopic and PCR techniques. Results obtained in this study show that the germination of mycoparasite ascospore in the presence of F. graminearum 3- and 15-ADON filtrates was greatly improved compared with Fusarium proliferatum and Fusarium sporotrichioides filtrates, suggesting a compatible interaction. Using quantitative real-time PCR with Fusarium-specific (Fg16N) and trichothecene Tri5 (Tox5-1/2)-specific primer sets, S. mycoparasitica was found to reduce the amount of F. graminearum 3-ADON and 15-ADON DNAs under separate coinoculation assays. Sphaerodes mycoparasitica was not only able to germinate in the presence of F. graminearum filtrates, but also established biotrophic mycoparasitic relations with two F. graminearum chemotypes and suppressed Fusarium growth. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the relationships between the biotrophic mycoparasite Sphaerodes mycoparasitica and pathogenic Fusarium strains. To study the interactions between S. mycoparasitica and four different phytopathogenic Fusarium strains, macroscopic observations were performed using dual-culture assays and microscopic examinations in combination with light and fluorescent microscopy. Both macroscopic and microscopic techniques were also vital in determining the host specificity of S. mycoparasitica with F. avenaceum, F. oxysporum, F. proliferatum, and F. sporotrichioides. Our results suggest that S. mycoparasitica established haustorial contact with F. avenaceum and F. oxysporum. Data obtained from the dual-culture assay and parasitism interactions revealed that this newly described contact biotrophic mycoparasitic fungus was capable of reducing F. avenaceum and F. oxysporum linear growth and size of hyphal cells through infection and penetration. [ABSTRACT FROM AUTHOR]