Experimental Infection of Host Grasses and Sedges with Atkinsonella hypoxylon and Balansia cyperi (Balansiae, Clavicipitaceae)

Abstract

Artificial infection of two grasses and one sedge with Atkinsonella hypoxylon and Balansia cyperi, respectively, is described. Prior inoculations of hosts with these and related fungi in the tribe Balansiae (Clavicipitaceae) have largely been unsuccessful. Seedlings grown in aseptic culture were infected by inserting mycelium and conidia with a needle above the meristem. Infection was evidenced by the presence of mycelium around meristems of new tillers 6–8 weeks after inoculation and by later production of stremata. Atkinsonella hypoxylon strains from populations of the grass Danthonia spicata were broadly cross-compatible but could not infect populations of Stipa leucotricha, another host. Strains of A. hypoxylon from S. leucotricha could infect their natural host but not D. spicata. Strains of B. cyperi from Cyperus virens and C. rotundus could infect C. virens but A. hypoxylon could not. The results suggest that there are distinct host races of A. hypoxylon. Infected seedlings of D. spicata produced 50% more tillers than noninfected seedlings after 10 weeks, indicating that this fungus enhances plant growth.