Format: ORAL

Alba Sotomayor-Alge1,2, Luis ngel Inda1,2, Mara Fernanda Moreno-Aguilar1,2, igo Zabalgogeazcoa3 Pilar Cataln1,2

1 Escuela Politécnica Superior de Huesca. Universidad de Zaragoza. Carretera de Cuarte Km 1. E-22071, Huesca 2 Grupo de Bioquímica, Biofísica y Biología Computacional (BIFI, UNIZAR, CSIC) 3 IRNASA-CSIC

Epichlo endophytes (Clavicipitaceae, Ascomycota) are known to colonize the aerial part of temperate pooid grasses and the nature of their antagonistic or synergistic interactions with their host depends on the ability of the endophyte to reproduce sexually or asexually. Most of these endophytes can only be transmitted vertically and asexually through plant seeds, establishing mutualistic symbiotic interactions with their hosts. We are investigating the potential co-evolution of holobionts comprised of Epichlo taxa and species complexes of the worldwide distributed grass genus Festuca (Loliinae, Poaceae). This genus encompasses ~500 accepted species, most of which had never been surveyed for their interactions with these endophytes before. To assess this matter, we are conducting a worldwide scale research collecting information about all the reported symbioses between these two genera and studying material from ~200 Festuca species through both genome sequencing and bioinformatic pipelines. So far, we can affirm that at least 14% of the Festuca species interact with Epichlo endophytes. Additionally, we unraveled the existence of natural symbioses between 15 Festuca species and 13 Epichlo taxa and we were able to detect 20 lineage- specific relationships for temperate and tropical mountain fescues and their endophytes, a fifth of which presumably correspond to new Epichlo endophytes. We have applied a multidisciplinary approach that included morphoanatomical, histological, cytogenetic and phylogenomic studies to analyze holobionts formed by the Festuca rothmaleri polyploid complex and their endophytes. This study suggests a hybridogenic adaptive co-evolutionary scenario where the increasing ploidy-level of the grass host (tetra, hexa and octoploid individuals) might be correlated with the ploidy-levels of their respective symbionts. This scenario offers an opportunity to better understand the co-evolutionary mechanisms involved in the establishment of these relationships.