Endophytic fungi occur inside healthy living plants. They are quite distinct from the fungi that grow on the surface of plants (epiphytic fungi).
Some endophytes have very clear roles (such as the Clavicipitaceae endophytes which help protect certain grasses from grazing and environmental stress). In most cases the role of these endophytici fungi is unknown, but they seem to range from beneficial to antagonistic in their interactions with plants. The relationship has been co-evolving for more than 300 Ma. This is evident by the fact that many endophytes will only infect certain hosts, for example Lophodermium species associated with genera in the plant family Pinaceae. Lophodermium is in the fungal order Helotiales which often dominate the fungal endophyte communities of gymnosperms, whereas angiosperms are often dominated by members the Diaporthales.
At RBGE endophyte research is centred on fungi associated with important forest trees such as the native Scots pine (Pinus sylvestris) and exotic conifers such as Sitka spruce (Picea sitchensis), Norway spruce (Picea abies) and Douglas fir (Pseudotsuga menziesii). Studies include basic empirical research to investigate the endophyte communities and also experimental work to determine effects such as relative importance of host provenance/genotype, and environmental factors, on endophyte communities, e.g. the recently completed PROTREE project. A further objective is to investigate these factors on the relationship of endophyte communities with fungal pathogens e.g. Dothistroma septosporum in pines. This research is carried out on above-ground host tissues after surface sterilisation using both the traditional isolation techniques and next generation sequencing.
Iason, G.R., Taylor, J.E. & Helfer, S. (2018) Community-based biotic effects as determinants of tree resistance to pests and pathogens. Forest Ecology and Management, 417: 301-312.
Gweon, H. S., Oliver, A., Taylor, J.E., Booth, T., Gibbs, M., Read, D. S., Griffiths, R. I. & Schonrogge, K. (2015). PIPITS: an automated pipeline for analyses of fungal internal transcribed spacer sequences from the Illumina sequencing platform. Methods in Ecology and Evolution, 6: 973–980.
Anderson Stewart, C., Taylor, J.E. & Doilom, M. (in press) Analysis of fungal endophytes of Sitka spruce in Scottish plantations shows extensive fungal infections, novel host partners, and provides insight into origins. Forest Pathology.
Taylor, J.E., Ellis, C., Ennos, R. & Hollingsworth, P. (in press) Endophyte species abundance responds contrastingly to tissue age and tree age in Scots Pine (Pinus sylvestris). Fungal Diversity.
Schönrogge, K., Gibbs, M., Oliver, A., Cavers, S., Gweon, H.S., Ennos, R., Cottrell, J., Iason, G. & Taylor, J.E. (in prep.) Shaping endophyte fungal communities: Lessons from common garden progeny trials of Scots Pine, Pinus sylvestris.
Jones, A. & Taylor, J.E., (in prep.) Fungal endophytes of Scottish plantation pines.
Good to Know
The endophytic stage is only part of the endophyte’s life cycle. Some endophytic fungi become saprophytic after senescence and death of the host plant tissue and produce spore bearing structures, which can be readily seen and studied. Others can become pathogenic and cause disease, particularly if the host plant becomes stressed. There are even examples of endophytic fungi which spend parts of their life cycle as saprophytes on dung or on dead wood in streams. In all these stages of the endophyte life cycle spores are produced, liberated into the environment and re-infect the living hosts. This is called horizontal transmission and the infections are mainly localised, although Clavicipitaceae endophytes of grasses can grow systemically and some exhibit vertical transmission via seeds.