Sphaerodes quadrangularisbiotrophic mycoparasitism onFusarium avenaceum

Abstract

Sphaerodes quadrangularis Garcia, Stchigel & Guarro was shown to be a facultative contact biotrophic mycoparasite of Fusarium avenaceum (Fr.) Sacc. (teleomorph: Gibberella avenacea Cooke) that established an intimate relationship with its host by producing hook-shaped and clamp-like attachment structures that appeared to derive nutrients and other essential factors from living host cells. The contact cells of the mycoparasite surrounded and envelop host hyphae and, although they do not appear to penetrate the host, the parasitized hyphae were significantly smaller than unparasitized controls. Sphaerodes quadrangularis did not form specialized attachment structures when cultured together with strains representing F. oxysporum and F. graminearum, indicating some degree of host specificity in the parasite.

Biotrophic mycoparasitic interactions betweenSphaerodes mycoparasiticaand phytopathogenicFusariumspecies

“…In comparison to polyspecific S. mycoparasitica, S. quadrangularis has been reported to be monospecific biotrophic mycoparasite (Goh and Vujanovic 2010). The ability of pyrenomycetous Melanospora, Sphaerodes, and Persiciospora mycoparasites to sporulate on Fusarium or other hosts was described to be one of the main criteria in determining host ranges (Harveson and Kimbrough 2001).…”

“…Hyphal interactions between mycoparasitic Sphaerodes and the four Fusarium strains were examined on the slide cultures and observations were made daily under 20), 40) and 100)objectives of the light microscope (Carl Zeiss Axioskop2) attached to a Carl Zeiss AxioCam ICc1 for up to 10 days. Hyphal diameters of Fusarium isolates infected (penetration) and non-infected (without penetration) by S. mycoparasitica were measured and recorded (Goh and Vujanovic 2010).…”

Guttation capsules containing hydrogen peroxide: an evolutionarily conserved NADPH oxidase gains a role in wars between related fungi

“…Contrary to antagonism and agonism (Chenthamara and Druzhinina, 2016), mycoparasitism should involve a prolonged contact stage between hyphae. Some fungi are obligate parasites and have specialized structures that allow them to invade the host (Goh and Vujanovic, 2010a;Marfetan et al, 2015). However, more fungi are facultative mycoparasites (Jeffries and Young, 1994).…”

Fungal Ecology: Principles and Mechanisms of Colonization and Competition by Saprotrophic Fungi

“…The establishment of biotrophic associations requires high specificity in recognition between the host and the mycoparasite (73). The associations are relatively nondestructive, with the cytoplasm of the host remaining relatively healthy, but abstraction of nutrients from the host results in reduction in host biomass, often causes distortion of host hyphae, and has adverse effects on host sporulation (73,75,76). Three subdivisons of biotrophic mycoparasitism have been described based on physiological characteristics.…”