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Pastoral agriculture underpins the New Zealand economy. Its success in generating export income is due to a mild and moist temperate climate, productive soils, innovative farmers supported by an effective research and development system, and an energy efficient production system based on year-round grazing. However, pastoral agriculture is entirely reliant on introduced pasture and forage species and their ability to withstand both endemic and introduced pasture pests. Critical to this is the mutualistic relationship between ryegrass and Epichloë fungal endophytes which provide a range of secondary metabolites that deter herbivory by both ruminants and insect pests. The challenge has been to identify and commercialise Epichloë strains which while providing protection against insect pests, ensuring ryegrass persistence, do not cause animal health and welfare issues. The critical role that Epichloë fungal endophytes play in maintaining pasture persistence and as a result the pastoral economy of New Zealand will be reviewed. [ABSTRACT FROM AUTHOR]

Definition: Asexual Epichloë are obligate fungal mutualists that form symbiosis with many temperate grass species, providing several advantages to the host. These advantages include protection against vertebrate and invertebrate herbivores (i.e., grazing livestock and invertebrate pests, respectively), improved resistance to phytopathogens, increased adaptation to drought stress, nutrient deficiency, and heavy metal-containing soils. Selected Epichloë strains are utilised in agriculture mainly for their pest resistance traits, which are moderated via the production of Epichloë-derived secondary metabolites. For pastoral agriculture, the use of these endophyte infected grasses requires the balancing of protection against insect pests with reduced impacts on animal health and welfare. [ABSTRACT FROM AUTHOR]

The relationship between Epichloë endophytes found in a wide range of temperate grasses spans the continuum from antagonistic to mutualistic. The diversity of asexual mutualistic types can be characterised by the types of alkaloids they produce in planta. Some of these are responsible for detrimental health and welfare issues of ruminants when consumed, while others protect the host plant from insect pests and pathogens. In many temperate regions they are an essential component of high producing resilient tall fescue and ryegrass swards. This obligate mutualism between fungus and host is a seed-borne technology that has resulted in several commercial products being used with high uptake rates by end-user farmers, particularly in New Zealand and to a lesser extent Australia and USA. However, this has not happened by chance. It has been reliant on multi-disciplinary research teams undertaking excellent science to understand the taxonomic relationships of these endophytes, their life cycle, symbiosis regulation at both the cellular and molecular level, and the impact of secondary metabolites, including an understanding of their mammalian toxicity and bioactivity against insects and pathogens. Additionally, agronomic trials and seed biology studies of these microbes have all contributed to the delivery of robust and efficacious products. The supply chain from science, through seed companies and retailers to the end-user farmer needs to be well resourced providing convincing information on the efficacy and ensuring effective quality control to result in a strong uptake of these Epichloë endophyte technologies in pastoral agriculture. [ABSTRACT FROM AUTHOR]