Invasive plants may cause a negative impact to native species due to competition for resources. This is the case of Poa annua, the only non-native plant species successfully established in Maritime Antarctica. Therefore, it is important to understand which factors could be driving the competitive success of P. annua, even despite the harsh environmental conditions. One of such factors is the establishment of novel mutualistic relationships with the resident soil fungi, which would improve plant growth and confer protection against stressful conditions. Additionally, plant-associated (endophytic) fungi could also participate in seedling development and establishment, by being vectored in seeds. Therefore, in this study we explored the composition and compared the diversity of fungal communities in different P. annua tissues (seeds, leaves and roots) with representative samples of Antarctic tundra soil by using ITS2 sequencing. Our results suggest that P. annua would have a strikingly different microorganism community compared with Antarctic soil, as only 6 amplicon sequence variants were shared among plants and soils therefore, it is plausible that the invasive success of P. annua is mediated by its' unique endophytes (rather than soil fungi).