Characterisation of Thozetella tocklaiensis isolated from the roots of three grass species in Waikato pastures, New Zealand

Abstract

In a mycological survey of Waikato pastures, Thozetella tocklaiensis was isolated from the roots of perennial ryegrass (Lolium perenne), sweet vernal (Anthoxanthum odoratum), and browntop (Agrostis capillaris). Initially, isolates grew as sterile dematiaceous mycelium in culture but when grown on nutrient poor media under near-UV light produced conidia in sporodochia characteristic of Thozetella tocklaiensis. Electron microscopy revealed that conidiophores within each sporodochium were surrounded by excipular hyphae which produced sterile microawns. The fungus produced sporodochia on roots of grass and clover seedlings and hyphae penetrated epidermal and cortical root tissue of seedlings without causing visible disease symptoms. This fungus has not previously been reported in New Zealand and is unrecorded from plant roots.

Keywords:

• Thozetella tocklaiensis
• pasture roots
• root-colonising
• sporulation
• microawns