INCIDENCE AND COMPATIBILITY OF NONCLAVICIPITACEOUS FUNGAL ENDOPHYTES IN FESTUCA AND LOLIUM GRASS SPECIES

The p-endophytes, previously identified as Gliocladium-like and Phialo phora-like fungi, constitute a group of closely related, seed transmis sible grass symbionts which have been found in several Festuca species and Lolium perenne, most often in cosymbiosis with mutualistic Epichl oe-type (Acremonium) endophytes (e-endophytes). To help assess the eco logical importance of p-endophytes, their incidence and the incidence of e-endophytes was determined in seed accessions of Festuca and Loliu m grass species in the U. S. Department of Agriculture Plant Introduct ion collection. Ten seeds of each accession were tested by tissue prin t immunoblot assay for the presence of eor p-endophytes in separate se eds, or together in individual seeds. A total of 370 accessions from 3 6 Festuca species and five Lolium species were tested. The e-endophyte s were present in 25 of the Festuca species and all of the Lolium spec ies, while the p-endophytes appeared in five and one species, respecti vely. The p-endophytes were present in 18 Festuca accessions and six L olium accessions, while the e-endophytes appeared in 121 and 43 access ions, respectively. The p- and e-endophytes were detected together in individual seeds in a total of five species and 13 accessions from bot h genera. Infectivity studies indicated that when p-endophytes from di fferent species were introduced into their own and reciprocal hosts on ly the endophytes introduced into their own hosts produced significant levels of sustainable infections. Three conclusions were inferred fro m this study: 1) The previously reported abundance of e-endophytes in Fesuca and Lolium grasses was substantiated. 2) Symbiosis of p-endophy tes, as indicated by seed dissemination, is not as common in these gra sses as e-endophyte symbiosis, suggesting that the p-endophytes are le ss ecologically important to the grasses, and may not be mutualists (t hey may be commensal or agonists). 3) Genotypes of p-endophytes can be host specific.