Poster #9

Rooted in Invasion: Unraveling fungal partnerships in Poa annua's Antarctic conquest
I. S. ACUÑA-RODRÍGUEZ, G. BALLESTEROS, M. A. MOLINA-MONTENEGRO
Centre of Integrative Ecology, Universidad de Talca, Campus Lircay, Av Lircay (s/n), Talca, Chile

Invasive plant species globally threaten native ecosystems. Poa annua L. (annual bluegrass) is a prominent invader, especially in Maritime Antarctica, endangering indigenous flora as the only successful plant invader at this extreme ecosystem. This study probes fungal endophytes' role in P. annua's invasiveness, leveraging global trends and Antarctic settings. Firstly, we scrutinized P. annua populations across four regions (Europe, South America, sub-Antarctica and Maritime Antarctica) to gauge endophyte influence on invasion traits. Antarctic plants exhibited notably higher endophyte frequency, correlating with enhanced germination, survival, and competitiveness against natives. Secondly, within Antarctic conditions, field experiments in Maritime Antarctica unveiled heightened germination rates and osmoprotection in endophyte-colonized seeds. Removal of endophytes led to diminished fitness and competitive ability. Significantly, seed fungal endophytes correlated with amplified allelopathic effects and competitive advantage over native plants. Additionally, metagenomic analysis unveiled distinct fungal communities associated with P. annua tissues (root, leaves and seeds), suggesting that the plant actively selects the endophytic fungal community “core” of its offspring. Our findings underscore the pivotal role of fungal endophytes in driving P. annua's invasiveness, both globally and within the distinct Antarctic ecosystem.