The Epichloë endophytes associated with the woodland grass Hordelymus europaeus including four new taxa

Abstract

Epichloë endophytes (Clavicipitaceae, Ascomycota), including asexual forms placed in Neotyphodium, are common in cool-season grasses. Here we characterize the endophytes of the European woodland grass Hordelymus europaeus based on growth characteristics, morphology of conidiophores and conidia and phylogenetic relationships. Of the six different taxa found on H. europaeus, four are new, for which we propose the species names E. hordelymi, E. disjuncta, E. danica and subspecies E. sylvatica subsp. pollinensis. The other two are assigned to previously described E. bromicola and E. sylvatica. E. hordelymi, E. disjuncta and E. danica are asexual interspecific hybrids, while the other taxa are haploid. Only E. sylvatica subsp. pollinensis was found to reproduce sexually on H. europaeus. The high diversity of endophytes may be explained by repeated host jumps to H. europaeus with and without subsequent interspecific hybridizations.

Interspecific hybridization and bioactive alkaloid variation increases diversity in endophyticEpichloëspecies ofBromus laevipes

“…Bromus laevipes has a narrow distribution limited to the United States west coast, yet the number of distinct Epichlo€ e species hosted by this grass, and the extensive chemotypic variation within, suggests that considerably more diversity exists within Epichlo€ e species in other hosts. Other studies have identified single host populations that harbor multiple endophyte species, but have not yet determined the chemotypic diversity among and between these species (Moon et al, 2004;Iannone et al, 2012;Leuchtmann & Oberhofer, 2013;Card et al, 2014;Oberhofer et al, 2014). Recent collections of the European woodland grass Hordelymus europaeus, spanning the latitudinal distribution transect of this host were found to associate with six distinct Epichlo€ e taxa (Oberhofer & Leuchtmann, 2012).…”

“…Phylogenetic placement of asexual vertically transmitted Epichloë species is either congruent with their sexual nonhybrid relatives, or heteroploid containing genomes from more than one progenitor, suggesting they arose from interspecific hybridization events. Such analyses coupled with estimations of host specificity suggest that hybridization among Epichloë species is a strikingly regular phenomenon (Moon et al ., ; Leuchtmann & Oberhofer, ; Leuchtmann et al ., ; McCargo et al ., ). Current data strongly suggest that interspecific hybridization occurs via somatic cell fusion or anastomosis followed by karyogamy (Schardl & Craven, ), as fertility barriers are strong between sexual Epichloë species and they lack a demonstrable vegetative incompatibility system (Chung & Schardl, ).…”

Endophyte species influence the biomass production of the native grassAchnatherum sibiricum(L.) Keng under high nitrogen availability

“…The existing results of the relationship are highly variable, ranging from mutualism (Brem & Leuchtmann, 2001;Crawford, Land, & Rudgers, 2010;Iannone et al, 2012;Nan, 1996;Ren et al, 2011;Rudgers & Swafford, 2009) to parasitism or commensalism (Faeth & Sullivan, 2003;Faeth et al, 2004;Hamilton & Faeth, 2005;Jani, Faeth, & Gardner, 2010;Morse et al, 2002;Saikkonen, Helander, Faeth, Schulthess, & Wilson, 1999). Generally, native grasses harbor a wider range of endophyte species compared with agronomic grasses (Iannone et al, 2012;Leuchtmann & Oberhofer, 2013;Shymanovich et al, 2015;Sullivan & Faeth, 2004;Zhang et al, 2009). For example, Leuchtmann and Oberhofer (2013) found that H. europaeus can harbor one of six endophyte species.…”

“…So far, multiple endophyte species have been reported from Festuca arizonica (Sullivan & Faeth, 2004), Achnatherum inebrians (Li, Nan, Paul, Dapprich, & Liu, 2004; Moon et al., 2007), Achnatherum sibiricum (Zhang et al., 2009), Bromus auleticus (Iannone, Pinget, Nagabhyru, Schardl, & De Battista, 2012), Hordelymus europaeus (Leuchtmann & Oberhofer, 2013), and Achnatherum robustum (Shymanovich et al., 2015). For example, Leuchtmann and Oberhofer (2013) found that H. europaeus was infected by one of six endophyte species in the grass population. Recent studies about the influence of endophyte infections on native grasses, however, have mostly compared E+ and E− hosts (Faeth, Bush, & Sullivan, 2002; Faeth, Helander, & Saikkonen, 2004; Gibert & Hazard, 2013; Gundel et al., 2013; Morse, Day, & Faeth, 2002; Ren et al., 2011; Saari, Helander, Faeth, & Saikkonen, 2010; Zhang, Fan, Li, & Nan, 2010).…”

“…In comparison with agricultural grasses, there are more endophyte species in naturally occurring native grass populations. So far, multiple endophyte species have been reported from Festuca arizonica (Sullivan & Faeth, 2004), Achnatherum inebrians (Li, Nan, Paul, Dapprich, & Liu, 2004;Moon et al, 2007), Achnatherum sibiricum (Zhang et al, 2009), Bromus auleticus (Iannone, Pinget, Nagabhyru, Schardl, & De Battista, 2012), Hordelymus europaeus (Leuchtmann & Oberhofer, 2013), and Achnatherum robustum (Shymanovich et al, 2015). For example, Leuchtmann and Oberhofer (2013) found that H. europaeus was infected by one of six endophyte species in the grass population.…”