AUTHOR=Geisen Stefan , Kostenko Olga , Cnossen Mark C. , ten Hooven Freddy C. , Vreš Branko , van der Putten Wim H. 

TITLE=Seed and Root Endophytic Fungi in a Range Expanding and a Related Plant Species

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01645

DOI=10.3389/fmicb.2017.01645

ISSN=1664-302X

ABSTRACT=<p>Climate change is accelerating the spread of plants and their associated species to new ranges. The differences in range shift capacity of the various types of species may disrupt long-term co-evolved relationships especially those belowground, however, this may be less so for seed-borne endophytic microbes. We collected seeds and soil of the range-expanding <italic>Centaurea stoebe</italic> and the congeneric <italic>Centaurea jacea</italic> from three populations growing in Slovenia (native range of both <italic>Centaurea</italic> species) and the Netherlands (expanded range of <italic>C. stoebe</italic>, native range of <italic>C. jacea</italic>). We isolated and identified endophytic fungi directly from seeds, as well as from roots of the plants grown in Slovenian, Dutch or sterilized soil to compare fungal endophyte composition. Furthermore, we investigated whether <italic>C. stoebe</italic> hosts a reduced community composition of endophytes in the expanded range due to release from plant-species specific fungi while endophyte communities in <italic>C. jacea</italic> in both ranges are similar. We cultivated 46 unique and phylogenetically diverse endophytes. A majority of the seed endophytes resembled potential pathogens, while most root endophytes were not likely to be pathogenic. Only one endophyte was found in both roots and seeds, but was isolated from different plant species. Unexpectedly, seed endophyte diversity of southern <italic>C. stoebe</italic> populations was lower than of populations from the north, while the seed endophyte community composition of northern <italic>C. stoebe</italic> populations was significantly different southern <italic>C. stoebe</italic> as well as northern and southern <italic>C. jacea</italic> populations. Root endophyte diversity was considerably lower in <italic>C. stoebe</italic> than in <italic>C. jacea</italic> independent of plant and soil origin, but this difference disappeared when plants were grown in sterile soils. We conclude that the community composition of fungal endophytes not only differs between related plant species but also between populations of plants that expand their range compared to their native habitat. Our results suggest that fungal endophytes of two <italic>Centaurea</italic> species are not able to systemically infect plants. We highlight that endophytes remain poorly studied and further work should investigate the functional importance of endophytes.</p>