Presence of Epichloë Fungus in the Endosperm-Side of the Seed Predicts the Symbiotic Status of the Seedling

GUNDEL P.E.; UENO A.; PANTEIX M.; IANNONE, L.J

Seed Technology Journal

AOSA/SCST Society of Comercial Seed Technologists

Lugar: Wichita; Año: 2019 vol. 39

1096-0724

Some important forage grasses of the genera Festuca and Lolium establish persistent symbiotic associations with vertically-transmitted fungal endophytes (genusEpichloë). In certain cases, the fungus is responsible of livestock intoxications due to fungal toxins that accumulate in the plant biomass. Killing the fungus from the seed is a possibility for getting rid of the problem. However, since the symbiosis is mutualistic, the inoculation of elite cultivars with non-toxic but still beneficial endophytes is a current breeding strategy.Additionally, the symbiosis has become a model of study in ecology and evolution, where the manipulation of the symbiotic status of plants is critical for the experiments. Here, we showed how checking the endophyte presence (or absence) in the endosperm-side of the seed, is a reliable technique to predict the symbiotic status of the seedling. The idea was originally proposed by Moore et al. (2015, Seed Sci. & Technol. 43:1?12.) but we complement it by (i)estimating the high correspondence between the infection status in one side of the seed (either + or -) and the infection status of the other side, and (ii) showing that cutting the seed in two halves does not affect either the seed germination, nor the normal seedling growth, nor the endophyte transmission to seedling. We also showed that cutting the seed reduced the seedling size, an impact that is increased by the endophyte presence provided the fungus is alive. We finally discuss the strengths and weaknesses of the technique as well as its potential use in other species.