Media Manipulations and the Culture of Beneficial Fungal Root Endophytes

Fungal endophytes have great potential as biocontrol and biofertilisation agents for food crops, and it is important to understand and optimise the cultural conditions for endophyte emergence and growth. A range of commercial culture media were tested for their effect on endophyte recovery from the roots of their host (Hordeum murinum), and for their subsequent growth and sporulation. Furthermore, a medium composed of sterile or filtered whole plant extract (WPE) was tested at various dilutions both alone and in combination with one of the commercial media. It was found that there were significant differences between the media in endophyte recovery, endophyte mycelial growth and time to sporulation. A significantly greater number of different endophytes were recovered from roots on the malt extract plus WPE medium than any of the other media tested here. Sabouraud medium gave the greatest mean radial growth of endophyte fungal mycelia after 35 days. The cultures growing on the WPE media took over five times longer to sporulate than all other media. Results indicate that different media are suitable either for the initial recovery and isolation of fungal root endophytes or for increasing fungal biomass and inducing earlier sporulation. The experimental endophytes used here have previously been shown to have biocontrol and biofertilisation benefits for barley cultivars, so our findings have important implications for the development and commercialisation of endophyte inocula.