PREMISE OF THE STUDY: Genome duplication is associated with multiple changes at different levels, including interactions with pollinators and herbivores. Yet little is known whether polyploidy may also shape belowground interactions. METHODS: To elucidate potential ploidy-specific interactions with arbuscular mycorrhizal fungi (AMF), we compared mycorrhizal colonization and assembly of AMF communities in roots of diploid and tetraploid Centaurea stoebe s.l. (Asteraceae) co-occurring in a Central European population. In a follow-up greenhouse experiment, we tested inter-cytotype differences in mycorrhizal growth response by combining ploidy, substrate, and inoculation with native AMF in a full-factorial design. KEY RESULTS: All sampled plants were highly colonized by AMF, with the Glomeraceae predominating. AMF-community composition revealed by 454-pyrosequencing reflected the spatial distribution of the hosts, but not their ploidy level or soil characteristics. In the greenhouse experiment, the tetraploids produced more shoot biomass than the diploids did when grown in a more fertile substrate, while no inter-cytotype differences were found in a less fertile substrate. AMF inoculation significantly reduced plant growth and improved P uptake, but its effects did not differ between the cytotypes. CONCLUSIONS: The results do not support our hypotheses that the cytotype structure in a mixed-ploidy population of C. stoebe is mirrored in AMF-community composition and that ploidy-specific fungal communities contribute to cytotype co-existence. Causes and implications of the observed negative growth response to AMF are discussed.

Department of Biology Ecology and Evolution University of Fribourg Chemin du Musée 10 CH 1700 Fribourg Switzerland

Department of Botany Faculty of Science Charles University Benátská 2 CZ 128 01 Prague Czech Republic

Department of Experimental Plant Biology Faculty of Science Charles University CZ 128 44 Prague Czech Republic

Ecology Department Climate and Ecosystem Sciences Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA

Institute of Botany Plant Science and Biodiversity Centre Slovak Academy of Sciences Dúbravská cesta 9 SK 845 23 Bratislava Slovakia

Institute of Botany The Czech Academy of Sciences CZ 252 43 Průhonice Czech Republic

Institute of Microbiology The Czech Academy of Sciences Vídeňská 1083 CZ 142 20 Prague Czech Republic

Citace poskytuje Crossref.org

Temporal stability of spatial cytotype structure in mixed-ploidy populations of Centaurea stoebe