RESEARCH PAPER Epichloae infection in a native South African grass, Festuca costata Nees D. A. McGranahan 1 , R. Burgdorf 2 & K. P. Kirkman 3 1 School of Natural Resource Sciences – Range Science, North Dakota State University, Fargo, ND, USA 2 Plant Pathology, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa 3 Grassland Science, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa Keywords Epichlo€ e; fungal endophytes; Neotyphodium; spatial scale of fungal endophyte infection. Correspondence D. A. McGranahan, School of Natural Resource Sciences – Range Science, North Dakota State University, Fargo, ND 58108, USA. E-mail: mcgranah@alumni.grinnell.edu Editor H. Rennenberg Received: 14 January 2015; Accepted: 16 January 2015 doi:10.1111/plb.12307 ABSTRACT Fungal endophytes have been documented in almost all terrestrial plant groups. Although the endophyte infection syndrome in agronomic cultivars is well studied, relatively little work addresses questions of spatial ecology and fire effects on epichloae endophyte infection in native grasses, and none, to our knowledge, in sub- Saharan Africa. We sampled seven populations of the native Festuca costata Nees along the spline of the Drakensberg range in South Africa at several spatial scales, including both recently burned and unburned stands. We tested epichloae presence and prevalence with immunoblot assays, PCR and genetic sequencing. We found epi- chloae endophytes were present and prevalent (38–98% infection rates depending on location). Variation in infection rates occurred primarily among locations, but also among bunches. There was little evidence that endophyte infection rates varied with fire. Novel evidence of epichloae infection of a native Festuca in South Africa opens the door to several new research questions, from the phylogenetic relationship between epichloae of sub-Saharan Africa and other continents to the ecological advan- tages or disadvantages that endophytes confer upon their hosts, especially in a fire- prone ecosystem vulnerable to global environmental change. INTRODUCTION Plant biologists frequently fail to consider that many, if not all, plant species host fungal endophytes (Rodriguez et al. 2009). Fungal endophytes are a diverse group that share two charac- teristics: they live inside – i.e. infect – plant tissue, but do not elicit disease symptoms in their host (Wilson 1995). While fun- gal endophytes are taxonomically diverse (Arnold et al. 2000), many are specialists associated with specific plant host taxa (Clay 1990). Indeed, the fungal family Clavicipitaceae primarily infects grasses (Poaceae; Clay 1989), and the epichloae, com- prised of Epichlo€e and Neotyphodium genera (Schardl 2010) and recently realigned under Epichlo€e (Leuchtmann et al. 2014), appears primarily associated with Poaceae subfamily Po€ oideae, the cool-season, C 3 grasses (Clay & Leuchtmann 1989). Plant–fungal endophyte associations among Po€ oideae genera Lolium and Festuca receive particular attention due to the con- sequences of infection. Lolium and Festuca are closely related genera within the Loliinae subtribe, often referred to collec- tively as the Lolium–Festuca species complex (Catalan et al. 2007; Inda et al. 2008; Hand et al. 2010). Species in the Loli- um–Festuca complex are so frequently infected by epichloae en- dophytes (White & Cole 1985) that the association was offered as evidence of their shared phylogeny prior to molecular con- firmation (McFarlane 1987). But epichloae produce toxic sec- ondary compounds (Schardl et al. 2013), and both livestock and wildlife that consume endophyte toxins can lose body con- dition and suffer reproductive decline (Fletcher 1982; Powell & Petroski 1993; Bacon 1995; Conover & Messmer 1996; Durham & Tannenbaum 1998; Tannenbaum et al. 1998). Toxicity aside, epichloae endophytes can confer advantages to host plants, and the economic importance of Lolium–Festuca forage species has spurred research into the ecological benefits of endophytes. Endophyte infection in various agronomic cul- tivars of Lolium–Festuca species has long been referred to as a mutualism, in which both fungus and host plant benefit (Clay 1990). When introduced to native grassland, endophyte bene- fits apparently increase the invasive potential of infected grasses (Clay & Holah 1999; Rudgers et al. 2005), which translates to enhanced stand longevity and weed resistance in agroecosys- tems (Malinowski & Belesky 2006; Saikkonen et al. 2013). Beyond agronomic Eurasian cultivars, however, endophyte relationships in native grasses globally are less well defined. In some cases, mutual antagonisms between endophytes and hosts qualify the relationship as a symbiosis (two organisms simply living together) rather than a mutualism (Schulz et al. 1999). In fact, for some host Festuca grasses, epichloae endophytes actually appear to be parasitic, reducing host plant competi- tiveness and long-term survival (Faeth & Sullivan 2003; Faeth et al. 2004; Faeth & Hamilton 2006). To gain a global perspective on grass–endophyte symbiosis, the geographical and ecological extent of these relationships must be understood. But research on fungal endophytes outside of Western countries has only recently begun. Both Festuca and epichloae species have been described throughout the Southern Hemisphere (Moon et al. 2002; Stancık & Renvoize 2007; Ian- none et al. 2013), but work in Africa lags behind. 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