An Epichloë endophyte associated with the Afromontane grass Festuca simensis

Abstract

Filamentous fungi of the genus Epichloë form symbiotic associations with Pooideae grasses (family Poaceae) with some estimated at 40 million years old, dating back to the origin of this grass subfamily. Here we provide a report on an Epichloë endophyte from central Africa associating with Festuca simensis, a tetraploid grass species of highland tropical African origin, potentially originated from a cross between a western Mediterranean F. fenas-type maternal parent and a Eurasian Lolium-type paternal parent, followed by genome duplication and likely colonisation of the Afromontane regions that cover the mountains of Africa and the southern Arabian Peninsula during the Pliocene epoch (5.3 to 2.6 million years ago). The endophyte of F. simensis most resembled Epichloë uncinata, a fungus generally associated with F. pratensis (= L. pratense; meadow fescue), with respect to its genetics, plant colonisation patterns and secondary metabolite profile. However, the F. simensis endophyte was slower to emerge from dissected plant tissue, had a significantly slower growth rate in culture and contained an additional copy of the β-tubulin gene, compared with E. uncinata. This paper reviews the preliminary knowledge gained about this intriguing Epichloë-grass symbiosis.