The Impact of Alkaloid-Producing Epichloë Endophyte on Forage Ryegrass Breeding: A New Zealand Perspective

Abstract

For 30 years, forage ryegrass breeding has known that the germplasm may contain a maternally inherited symbiotic Epichloë endophyte. These endophytes produce a suite of secondary alkaloid compounds, dependent upon strain. Many produce ergot and other alkaloids, which are associated with both insect deterrence and livestock health issues. The levels of alkaloids and other endophyte characteristics are influenced by strain, host germplasm, and environmental conditions. Some strains in the right host germplasm can confer an advantage over biotic and abiotic stressors, thus acting as a maternally inherited desirable ‘trait’. Through seed production, these mutualistic endophytes do not transmit into 100% of the crop seed and are less vigorous than the grass seed itself. This causes stability and longevity issues for seed production and storage should the ‘trait’ be desired in the germplasm. This makes understanding the precise nature of the relationship vitally important to the plant breeder. These Epichloë endophytes cannot be ‘bred’ in the conventional sense, as they are asexual. Instead, the breeder may modulate endophyte characteristics through selection of host germplasm, a sort of breeding by proxy. This article explores, from a forage seed company perspective, the issues that endophyte characteristics and breeding them by proxy have on ryegrass breeding, and outlines the methods used to assess the ‘trait’, and the application of these through the breeding, production, and deployment processes. Finally, this article investigates opportunities for enhancing the utilisation of alkaloid-producing endophytes within pastures, with a focus on balancing alkaloid levels to further enhance pest deterrence and improving livestock outcomes.

Ergot Alkaloids Mycotoxins in Cereals and Cereal-Derived Food Products: Characteristics, Toxicity, Prevalence, and Control Strategies

“…Claviceps purpurea, Claviceps fusiformis, Claviceps africana, Epichloë spp., and Neotyphodium spp. are some EA producers [12,33,34]. Moreover Blansia, Penicillium, and Aspergillus also produce some quantity of EAs [20].…”

Quantitation and Distribution of Epichloë-Derived Alkaloids in Perennial Ryegrass Tissues

“…Although terpendole E has been identified as non-tremorgenic [ 55 ], its role in synthesizing tremorgenic terpendole C and lolitrem B is of interest. In a review article, Eady et al noted that a non-lolitrem-producing endophyte strain (NEA3) caused ryegrass staggers in livestock [ 56 ]. The perennial ryegrass-NEA3 symbiotes contained higher levels of paxilline and terpendole C compared to perennial ryegrass-SE in the same study, indicating that these compounds may have been responsible.…”

ERGOT Claviceps purpurea (Fries) Tulasne ALKALOID DIVERSITY AND VIRULENCE: EVOLUTION, GENETIC DIVERSIFICATION, AND METABOLIC ENGINEERING (review)

“…В последние годы в качестве перспективного подхода можно рассматривать управление симбиозами растений и эндофитов для оптимизации профиля и концентрации продуцируемых вторичных метаболитов (в том числе токсичных для человека и сельскохозяйственных животных) (231,233). Значимыми остаются филогенетические исследования и изучение эволюционной изменчивости спорыньи (234).…”