Incompatibility of some grass-Acremonium endophyte associations

Reactive Oxygen Species Play a Role in Regulating a Fungus–Perennial Ryegrass Mutualistic Interaction

“…A striking feature of these symbiotic associations is the apparent lack of any host defense reaction to the presence of the endophyte. However, introduction of Epichloe¨endophytes into related nonnatural hosts frequently results in a host defense reaction that can vary in severity, from a high level of seedling mortality and stunting of the surviving plants (Christensen et al, 1997), to more localized responses such as the death of host cells in the stem apex (Christensen, 1995), to premature death of the hyphae (Koga et al, 1993). This loss of regulated endophyte growth and compatible interaction with the host in some novel associations reveals an underlying signaling mechanism between host and endophyte that maintains the mutualistic interaction.…”

Peroxidase activity of perennial ryegrass and tall fescue seedlings artificially infected with endophytes

“…Such [3,9,13,21]. However, some of these novel associations showed incompatibility reactions such as the presence of stunted tillers on the new host [3] or the degeneration of endophyte hyphae [9].…”

Creation of stable associations between perennial ryegrass or tall fescue and fungal endophytes

“…This author suggested that the lack of host specificity probably reflected the very close genetic relationships between perennial ryegrass, tall fescue and meadow fescue. Koga et al [17] [20], Koga et al. [17], Christensen [4], Christensen et al [7], show that it could be possible to enlarge the selection of strains to endophytes of other grass species.…”

“…Koga et al [17] [20], Koga et al. [17], Christensen [4], Christensen et al [7], show that it could be possible to enlarge the selection of strains to endophytes of other grass species. As regards Lolium perenne, in addition to the two natural e-endophytes of this host, the selection could also concern Epichloe festucae, a species which, in our experiment, was 100 % transmitted to the seeds of perennial ryegrass and did not show any harmful effect on this host.…”

“…However, some evidence of incompatibility can be observed when an isolate is introduced into another host, even if it is not very distant from the original one; incompatibility can concern either the fungus which shows distorted, vacuolized hyphae, as when N. coenophialum is introduced into Lolium perenne [4,17] or the host; for instance, Christensen [4], observed the death of host tissues of the shoot apices of tall fescue infected with N. uncinatum or LpTG-2, while Christensen et al [7] reported that [18]), the transmission of the mycelium of the endophyte to the seeds of the inoculated plant has not been studied, so it is not really possible to assess the stability of these artificial associations.…”