Ecological importance of Neotyphodium spp. grass endophytes in agroecosystems

Abstract

Neotyphodium spp. fungal endophytes form symbiotic associations with agronomic grasses with expression ranging from mutualistic to parasitic. In general, endophyte infection frequencies seem more variable in natural compared to pastoral situations, suggesting that expression and benefits attributable to endophyte infection depend on the resource environment in which the host–endophyte complex was formed and the conditions under which it is being grown. Emerging evidence suggests that expression is not always mutualistic or beneficial to the host in terms of productivity and persistence in resource‐limited environments. Expression of host–endophyte associations will vary depending on resource availability and environmental conditions that influence host physiology and growth, and herbivore behavior. New research suggest alkaloids and secondary metabolites produced by host–endophyte associations can have physiological functions in addition to acting as herbivore deterrents. Novel host–endophyte associations are being created that maintain insect and disease resistance, while having minimal detrimental impact on mammalian herbivores. The influence of host–endophyte associations on sward composition and soil food webs is only now coming to light. While novel endophyte associations and their attendant mechanisms can be considered beneficial in some respect, the associations may not be as adaptable to stressful or marginal resource environments and could have long‐term ecological impacts measured in terms of persistence and total productivity of the sward. We review the extensive published work on host–endophyte interactions and illustrate the complexity of host–endophyte associations and their interactions with environment, and the range of responses that occur.

Effect of Neotyphodium endophyte-tall fescue symbiosis on mineralogical changes in clay-sized phlogopite and muscovite

“…Therefore, E + grasses not only have adaptative advantages in stress environments, but can modify soil environments to ensure some competitive advantages. One explanation for better competitiveness of E + plants may be endophyte metabolites produced and released into the rhizosphere from fresh and dead plant material (Malinowski and Belesky 2006). Secondary metabolites of host-endophyte associations could be also involved in the fast weathering of micas in E + rhizospheres.…”

Plant Bioactive Metabolites and Drugs Produced by Endophytic Fungi of Spermatophyta

“…We also do not consider the complex case of the endophytic fungi inhabiting a series of fodder plants, which cause noxious effects to livestock because of their attitude to permeate host tissues with mycotoxins, and are also able to produce phytohormones [8][9][10]. A few excellent reviews on this bordering subject are available in the literature [11][12][13].…”

Metabolic Profiles ofLolium perenneAre Differentially Affected by Nitrogen Supply, Carbohydrate Content, and Fungal Endophyte Infection

“…Marks and Clay (1996) demonstrated an endophyte by temperature interaction, and Newman et al (2003) found an endophyte by N interaction on photosynthetic rates. Effects of endophyte infection on growth also strongly depend on host genotype, resource availability, and environmental stress (Belesky et al, 1989;Malinowski and Belesky, 2006;Morse et al, 2002;Cheplick and Cho, 2003;Hesse et al, 2003;Zabalgogeazcoa et al, 2006;Cheplick, 2007). In our study we saw significant cultivar by endophyte interactions on the regrowth of blades, which was only stimulated in 'AberDove' plants infected with the endophyte strain AR37, clearly demonstrating the importance of specific host plant-endophyte strain interactions and environmental conditions on overall physiological outcomes of the association.…”