) Dumort]) has been widely used as forage and turf grass in the United States for decades (Ball et al. 1993). Thus, one of the most studied grass–endophyte associations is the N. coenophialum AR-13324 solubility dmso and tall fescue symbiosis (Saikkonen et al.

2006, 2010). Tall fescue cultivars are dominated by a widely-adapted cultivar named “Kentucky 31” (hereafter referred to as K-31), which has a long growing season and is resistant to pests, selleck chemicals llc drought, poor soil conditions, and variations in soil pH (Ball et al. 1993). Based on the research of this grass–endophyte system, the relationship between the endophytic fungus and its host has generally been thought to be mutualistic (Clay 1988; Clay et al. 1993; Saikkonen et al. 2006; Schardl and Phillips 1997). Recent studies have shown, however, that this relationship can vary from mutualism LCZ696 mw to antagonism, depending on the genotype of the fungus and the host as well as environmental conditions, especially in native grasses (Cheplick et al. 1989; Cheplick and Faeth 2009; Faeth 2002; Faeth and Saikkonen 2007; Faeth and Sullivan 2003). Saikkonen et al. (1998, 2004, 2006) therefore proposed that the prevailing concept of endophytes as mutualists is likely historical and system based rather than based on evidence from natural populations. In the case of the tall fescue–N. coenophialum symbiosis,

much of the research has been done in the United States on agronomic cultivars such as K-31 (Saikkonen et al. 2006), although the origins of this grass are in Eurasia. In these agronomic cultivars planted outside their native distributional range, Neotyphodium is widely known to cause detrimental effects (e.g., toxicosis) on vertebrate grazers in high-nutrient agronomic environments (Ball et al. Paclitaxel mw 1993; Clay 1989, 1990; Saikkonen et al. 2006, 2010; Schardl and Phillips 1997). These effects are related to high concentrations of alkaloids (Clay 1990; Lyons et al. 1986), which are known to deter both vertebrate and invertebrate herbivores (Bacon

1995; Bacon et al. 1977; Bazely et al. 1997; Siegel and Bush 1996, 1997; Vicari et al. 2002). Because alkaloids are nutrient-rich compounds, their synthesis has cost to other basic plant growth and reproductive functions (Faeth 2002; Faeth and Bultman 2002; Faeth and Fagan 2002). These costs may outweigh the benefits of the endophyte infection in most environments, but particularly so in nutrient-poor environments in nature (Ahlholm et al. 2002; Faeth 2002; Lehtonen et al. 2005). Thus, in its native habitat, infected wild tall fescue may produce lower levels and fewer types of alkaloids than its cultivated and selective-bred varieties in nutrient-rich environments in the introduced range (Saikkonen et al. 1998, 2010; Siegel and Bush 1996; but see Piano et al. 2005). Recent evidence supports this idea: (1) the levels and composition of alkaloids produced varies among fungal species and genotypes (e.g., Piano et al.