Olpitrichum tenellum as a biotrophic contact mycoparasite

Abstract

Olpitrichum tenellum was shown to be a biotrophic mycoparasite, contacting but not penetrating its host hyphae by means of hook-shaped contact cells, which apparently absorb nutrients and growth factors from living host cells. The known hosts are Fusarium moniliforme, Alternaria alternata, and Cladosporium sp. The hyperparasite failed to grow in the absence of the host on glucose – yeast extract medium unless a water extract of the host was added. Keywords: Olpitrichum tenellum, mycoparasite, axenic culture, hyperparasite.

Biotrophic mycoparasitic interactions betweenSphaerodes mycoparasiticaand phytopathogenicFusariumspecies

“…Formation of hook-like contact structures by M. zamiae were seen occurring on Fusarium and Tritirachium species (Jordan and Barnett 1978), as were the generation of both hookand clamp-like structures by Stephanoma phaeospora on Fusarium, Cladosporium, and other ascomycetes (Rakvidhyasastra and Butler 1973), and hook-shaped contact cells by Olpitrichum tenellum on Fusarium, Alternaria, and Cladosporium species (Li and Shen 1996). These structures were also observed in this study, but only by S. mycoparasitica on F. oxysporum and F. avenaceum hosts ( Figure 3).…”

“…20, No. 9, 2010 (Li and Shen 1996), Persiciospora moreaui (Harveson and Kimbrough 2000), Sphaerodes retispora (Harveson and Kimbrough 2001), and Gliocephalis hyalina (Jacobs, Holtzman, and Seifert 2005). These groups were described and proposed to show mycoparasitic characteristics towards Fusarium strains.…”

Sphaerodes quadrangularisbiotrophic mycoparasitism onFusarium avenaceum

“…S. quadrangularis is not an obligate biotroph and was able to grow on all tested media. Obligate biotrophic mycoparasitic fungi, such as G. hyalina and O. tenellum, failed to grow on conventional or commercial media when the host is absent (Jacobs et al 2005, Li andShen 1996). Therefore S. quadrangularis would be best considered a facultativecontact instead of an obligate biotrophic mycoparasite and, based on our results, the strain of F. avenaceum would be a preferred host when compared with the other three strains tested.…”

“…These structures or cells were similar to branches or contact structures generated by other pyrenomycetous biotrophic mycoparasites (FIG. 2A-C), such as M. zamiae, O. tenellum and P. moreaui, on their respective hosts (Harveson and Kimbrough 2000, Hoch 1978, Jordan and Barnett 1978, Li and Shen 1996. Furthermore hook-shaped contact cells also have been reported in the interactions between the biotrophic mycoparasitic Sphaerodes retispora and Fusarium oxysporum (Harveson and Kimbrough 2001) and among S. mycoparasitica and F. avenaceum, F. oxysporum and F. graminearum species (Vujanovic and Goh 2009).…”

“…These two groups are based on differences in host-parasite interfaces, parasitic modes and effects of parasites on hosts (Boosalis 1964, Jeffries 1995, Jeffries and Young 1994. Three types of biotrophic mycoparasitic relationships have been described: (i) intracellular or internal parasitism, represented by the thallus of most chytrids that enter and develop within host cells or hyphae; (ii) haustorial parasitism, in which penetration of host cells occurs through the formation of appressoria on host hyphae and the formation of specialized absorptive branches (haustoria) within host cells; and (iii) fusion or contact parasitism in which nutrients are absorbed from the host through absorptive or contact cells that develop on cells of the host instead of within them (Barnett 1963, Barnett 1964, Jeffries 1995, Li and Shen 1996. In these biotrophic mycoparasitic interactions the cytoplasm of the host cell remains healthy (Jeffries 1995 kendall et al 1983), Dispira simplex R.K. Benj.…”