IRNA-CSIC, Cordel de Merinas 40-52, 37008 Salamanca, Spain
UMR INRA-ENVL 188, Métabolisme et Toxicologie Comparés des Xénobiotiques, Ecole Vétérinaire de Lyon, B.P. 83, Marcy l'Etoile, 68280, France
Festuca ampla is native to the Iberian Peninsula (4). Endophytic mycelium was observed by microscopy (2) in stem pith samples of two of eight asymptomatic plants of F. ampla collected in one population from a natural grassland in Salamanca, Spain. The fungus could be isolated (2) only from these two plants, and conidiophores and reniform conidia typical of Epichloe species (3) were observed in pure cultures. The two infected plants maintained in pots outside, developed ectostromata in some reproductive stems (choke disease) the year after the field sampling. Six seeds collected from an infected plant were germinated, and all six seedlings were found to be infected based on microscopy (2), implying seed transmission of the endophyte. These observations suggest that this is a pleiotropic symbiont, having both mutualistic and pathogenic states in its host. An ergovaline concentration of 120 ng/g dry weight was detected in a sample of leaves and leaf sheaths of an infected plant. All of the above characteristics are typical of the genus Epichloe, and in particular of the fine fescue endophyte E. festucae (1,3). To determine the species, internal transcribed spacer and 5.8-rDNA sequences as well as a partial sequence of the β-tubulin gene were obtained. These two sequences (EMBL Accession Nos. AJ488497 and AJ488498) showed 100% sequence homology to the corresponding sequences in E. festucae. To our knowledge, this is the first report of this endophyte species in the grass F. ampla.
References: (1) L. P. Bush et al. Plant Physiol. 114:1, 1997. (2) E. M. Clark et al. J. Microbiol. Methods 1:149, 1983. (3) A. Leuchtmann et al. Mycologia 86:802, 1994. (4) I. Markgraff-Dannenberg. Festuca. Pages 125--153 in: Flora Europaea, Vol 5. Cambridge University Press, Cambridge, 1980.