Neotyphodium endophytes: incidence, diversity, and hosts in South America.

CABRAL, D.; NOVAS, M.V.; WHITE, J.

Soest, Alemania

Conferencia; Grassland Conference 2000; 2000

Few studies have characterised the distribution, incidence, and diversity of endophytes in native grasses over wide geographical areas. South America, because of its diversity of climates, soils, and varied topography and vegetation, is an ideal place to survey native grasses for Neotyphodium endophytes and related sexual states. A 10-year survey in Argentina and neighbouring countries recorded endophytes in native grasses, with 33 infected species (14 Festuca, 14 Poa, 2 Bromus, 2 Melica, and Phleum commutatum). Endophytes were placed in the genus Neotyphodium using a variety of methods (morphology, isozyme analysis, rDNA); however, our research demonstrated that these endophytes are different from Neotyphodium fungi described in North Hemisphere. A new Neotyphodium species was isolated from three host species. Teleomorphs were not recorded. In addition, the survey revealed a definitive pattern of distribution of endophyte-infected grasses across different ecological zones. For example, endophyte-infected grasses were not recorded in the "humid pampa" in the central part of eastern Argentina, but grasses in the "dry pampa" harboured endophytes with higher numbers of infected plants in the western part of this grassland habitat. The number of infected grasses was significantly higher in the Andes and the southern Patagonia region. Overall, the number of infected grasses increased from east to west and from north to south.. We also investigated the occurrence of infected plants in widely distributed host grasses, namely Bromus setifolius, Phleum commutatum, and Poa rigidifolia. Vesicular-arbuscular mycorrhizae were much more prevalent on endophyte-infected B. setifolius than on uninfected conspecifics.