CONICET | Buscador de Institutos y Recursos Humanos

Asexual epichloë-endophytes have been detected in more than 30 grass species native to Argentina, but only the endophytes from 10 host species have been characterized at a molecular level. In this work we developed specific primers for sequencing the calmodulin A gene (calA) in order to perform phylogenetic analyses of epichloë endophytes from 19 different hosts from Argentina. The resulting phylogenies were compared with those obtained using previously described markers tubB and tefA. The endophytes were also characterized by diagnostic PCR for the detection of some of the genes involved in the biosynthesis of lolines (lolC), ergot alkaloids (dmaW) and lolitrem B (ltm genes). The calA phylogeny was consistent with tubA and tefA phylogenies, confirming the hybrid origin of most of the endophytes and revealing the existence of a wide diversity of these fungi. At least, three different lineages were recognized, the previously known hybrid species N. tembladerae and N. pampeanum and a new species, Neotyphodium cabralii, which only included isolates from Phleum alpinum. This diversity was also detected in the alkaloid gene profiles of the endophytes. The lolC gene was not detected in the endophytes characterized as N. tembladerae, but its presence in N. pampeanum, N. cabralii, and endophytes from Poa lanigera and P. spiciformis indicating that these endophytes might produce some kind of loline. Screening for ltm genes indicated that cluster 3 is lost in the endophytes from Argentina, and cluster 1 is lost in N. pampeanum and N. cabralii. Lolitrem clusters 1 and 2 gene compositions were very variable among Neotyphodium tembladerae strains, and dmaW was not detected in any of the endophytes studied. Thus, the endophytes from Argentina are not expected to produce ergot alkaloids or lolitrem B, but precursors of lolitrem B might be produced by N. tembladerae from different hosts.