Species diversity of Epichloe symbiotic with two grasses from Southern Argentinean Patagonia"

MC CARGO, P. D.; IANNONE, L. J.; VIGNALE, M. V.; SCHARDL C.L.; ROSSI, M. S.

MYCOLOGIA.

ALLEN PRESS INC

Lugar: Lawrence; Año: 2014 vol. 106 p. 339 - 352

0027-5514

Neotyphodium tembladerae is the predominant epichloid endophyte in Argentina; however previous studies suggested the existence of other species in grasses from the Argentinean Patagonia. In this work we performed morphological and molecular phylogenetic analyses (based on sequences of calmodulin M [calM], translation-elongation factor 1-α [tefA] and β-tubulin [tubB] genes) to characterize the diversity of epichloae in Bromus setifolius and Phleum alpinum. The phylogenies obtained from the three genes were congruent and allowed to differentiate three lineages of endophytes that also presented morphological differences. One lineage corresponds to the previously described species Neotyphodium tembladerae, which is present in a wide range of native grasses from Argentina including B. setifolius and P. alpinum. Other genotype, only isolated from B. setifolius, is a non-hybrid endophyte, a rare condition for the South American epichloae. This isolates presented waxy colonies at maturity and a very low production of conidia, and we propose to be considered a new variety named Epichloë typhina var. aonikenkana. The third genotype, exclusively found in isolates of P. alpinum, is a hybrid between E. typhina and a common ancestor of E. amarillans and E. baconii. Isolates of this lineage produced abundant conidia, very variable in shape and size. Based on its phylogenetic position and morphology, we propose these isolates to be considered a new species, Epichloë cabralii. The new combinations Epichloë tembladerae and E. pampeana are also proposed for the previously described N. tembladerae and N. pampeanum species.