A rapid seedling screening method for determination of fungal endophyte viability

Infection of turf and forage grasses with Acremonium Link:Fr. and Epichloe (Fr.) Tul. & C. Tul. fungal endophytes is often desirable because it confers enhanced insect tolerance to these plants. Determination of the viability of the endophytes in seed lots is important for commercial producers and consumers of seed. A current method of determining viability relies on staining leaf sheath epidermal peels for the presence of endophyte hyphae. It is difficult to obtain an epidermal peel from a young seedling, so plants must often be grown for several months before checking for viability. The objective of this study was to develop a method of screening very young seedlings for endophyte viability. Here it is reported that endophyte viability could be determined within 2 to 3 wk of germination by staining intact leaf sheath tissue with an alkaline rose bengal stain. This method of endophyte detection allows a more rapid assessment of percentage of viable endophyte in a seed lot.