All of these were abundantly produced by S. mycoparasitica on F. graminearum Selleckchem Galunisertib hyphae. Formation of these structures as well as haustorial penetration appeared 2 days later in F. graminearum than in F. avenaceum and F. oxysporum (Goh & Vujanovic, 2010). Soon after, S. mycoparasitica sporulated on F. avenaceum and F. oxysporum (Goh & Vujanovic, 2010), as well as on both F. graminearum chemotypes as presented in this study. Sporulation is an additional criterion for determining mycoparasite host ranges because melanosporaceous biotrophic mycoparasites were observed to undergo sporulation on specific Fusarium isolates only (Harveson & Kimbrough, 2001a, b). The germination test of S. mycoparasitica
ascospores in Fusarium filtrates showed that F. graminearum is one of the principal hosts of the mycoparasite, together with F. avenaceum and F. oxysporum. In contrast, F. proliferatum and F. sporotrichioides do not appear to be hosts. A few biotrophic,
mycoparasitic fungi (Gonatobotrys, Dicyma, Stephanoma, Melanospora and Piptocephalis) acquire certain nutrients (mycotrophein, biotin or aneurin) from their hosts for growth and generation of sexual reproductive organs (Hawker, 1938; Jeffries & Young, 1994; Rakvidhyasastra & Butler, 1973; Whaley & Barnett, 1963). During interactions with F. graminearum 3-ADON (but not with 15-ADON) and by an as yet unknown mechanism, S. mycoparasitica removed the pathogen red-colored compounds, possibly aurofusarin (Kim et al., Gefitinib 2005), and subsequently released crystal-like red-colored substances (Fig. 3). We hypothesize that S. mycoparasitica absorbs aurofusarin from attacked Fusarium cells through lysis of the pathogen membrane components, such as chitin by production of chitinase and chitosanases (Goh & Vujanovic, 2010; Manocha, 1987). This property of S. mycoparasitica could imply detoxification or neutralization of aurofusarin, a notable F. graminearum mycotoxin ALOX15 (Dvorska et al., 2001; Dvorska & Surai, 2004). Moreover, trichothecene mycotoxins
may play an important role in the aggressiveness of F. graminearum towards plant hosts (Doohan et al., 1999). In this study, S. mycoparasitica demonstrated a capacity to markedly reduce the amount of Tri5 gene fragments in both 3-ADON and 15-ADON strains (P=0.05). Mycoparasitic biodegradation of mycotoxins is often related to production of lactonase enzymes involved in mycotoxin hydrolysis. Gliocladium roseum, a mycoparasite, showed detoxification of zearalenone mycotoxin through hydrolysis of fungitoxic zearalenone by these catalysts, followed by a spontaneous decarboxylation (Utermark & Karlovsky, 2007). A previous study highlighted degeneration of the cytoplasm of F. avenaceum and F. oxysporum hyphal cells challenged with S. mycoparasitica (Goh & Vujanovic, 2010). In this study, linear growth of both F. graminearum chemotypes was significantly decreased in the presence of S. mycoparasitica (Fig. 4), with similar cytoplasmic breakdown.