Festulolium and fungal endophyte associations: host status for Meloidogyne incognita and nematotoxic plant extracts

Authors: Meyer, Susan; PATCHETT, B - Christchurch Science Center; GILLANDERS, TIMOTHY - Christchurch Science Center; KANTOR, MIHAIL - Oak Ridge Institute For Science And Education (ORISE); Timper, Patricia - Patty; Macdonald, Margaret

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2020
Publication Date: 7/28/2020
Citation: Meyer, S.L., Patchett, B.J., Gillanders, T., Kantor, M., Timper, P., MacDonald, M.H. 2020. Festulolium and fungal endophyte associations: host status for Meloidogyne incognita and nematotoxic plant extracts. Journal of Nematology. 52:1-16. https://doi.org/10.21307/jofnem-2020-076.
DOI: https://doi.org/10.21307/jofnem-2020-076

Interpretive Summary: Plant-parasitic nematodes are small worms that attack crop plants and cause U.S. crop losses of ten billion dollars each year. Festulolium is an important forage grass used for pastoral agriculture in temperate climates around the world. However, Festulolium has not been widely studied to determine if it is attacked by plant-parasitic nematodes. Festulolium grasses are associated with a fungus that grows within the plants, aiding in nutrient uptake, drought tolerance, and production of compounds that protect against parasites and herbivores. This fungus produces compounds that can deter insect pests. In this study, different Festulolium lines, with and without beneficial fungi, were tested in the greenhouse to determine if they were hosts for root-knot nematode, which is an economically important pathogen on many crop plants. All Festulolium lines were poor hosts, whether the fungus was present or not. However, when the Festulolium plants were harvested and pepper seedlings planted into the same pots, pepper plants were attacked by the nematodes. Extracts from the shoots and roots of one Festulolium line did not reduce root-knot nematode egg hatch, but killed nearly a third of the nematodes whether the plant had been associated with a fungus or not. These results are significant because they indicate that Festulolium may be a poor host for nematodes in fields. The results will be used by researchers and by growers using Festulolium as a forage grass.

Technical Abstract: Festulolium hybrids are forage grasses used worldwide in temperate climates. They are associated with the fungal endophyte Epichloë uncinata, which aids in nutrient uptake, drought tolerance, and production of metabolites that protect against parasites and herbivores. Epichloë uncinata produces loline alkaloids, which can deter insect pests. Festulolium has not been widely studied for susceptibility to plant-parasitic nematodes, so Festulolium lines, with and without fungal endophytes, were tested in the greenhouse for host status to the root-knot nematode Meloidogyne incognita. All were poor hosts, regardless of line or endophyte status. Pepper seedlings planted into soil following removal of the Festulolium plants were infected by nematodes, likely because of surviving nematodes from the original inoculation combined with some reproduction on Festulolium. Lolines were found in shoots and roots of all endophyte-associated lines, and some types of lolines in roots increased after nematode infection. Methanolic extracts from roots and shoots of a tested Festulolium line did not inhibit egg hatch, but killed nearly a third of second-stage juveniles whether an endophyte was present or not. Further studies would indicate whether these Festulolium lines aid in suppressing field populations of M. incognita.