A fungus living within the tissues of grasses may cause record growth in the host and protect the plant from being eaten.
Fungi that live within plants – that is, endophytic fungi – do not cause problems to the host plant, but may in fact benefit it.
“Endophytes substantially increase biomass, seed production and competitive ability against weeds,” says Professor Kari Saikkonen from Natural Resources Institute Finland (Luke).
Saikkonen and Marjo Helander, a researcher from the University of Turku, have been studying grasses since the mid-1990s.
The relationship between fungi and grasses is already well known in America and New Zealand, and utilised in breeding.
“When you buy grass seeds in New Zealand and the United States, it says on the bag whether fungi are present,” says Professor Saikkonen.
The fungi create a variety of alkaloids, that is, compounds of which some are detrimental to invertebrates, and some even to vertebrates. This is why aphids, for example, like to stay away from endophytic meadow fescue – and as a result block the spread of barley yellow dwarf virus carried by aphids.
“Endophytic meadow fescue could be sown as a protective strip for grain crops,” says Professor Saikkonen.
Endophytes created by meadow fescue’s big brother, tall fescue, on the other hand, can create compounds that are harmful to even large vertebrates.
Cattle ranchers in North America in particular have suffered losses on dry and hot summers by the fungal toxins created by the tall fescue endophytes.
“They are also working on new varieties of tall fescue that would only have the good properties of endophytes. However, meadow fescue endophytes have not been found to have any alkaloids that are harmful to vertebrates,” continues Saikkonen.
The fungus may also disappear with time. This may be the reason for the sudden changes in the properties of grasses and the large variation among seed lots.
“The fungus may have disappeared if the seeds have been kept in too warm a place or if they are from the previous year. The death of the fungus may change the plant’s properties considerably,” says Professor Saikkonen.
Text: Niina Pitkänen, Luke