Global population genomics of pine-co-introduced ectomycorrhizal fungus Suillus luteus
YI-HONG KE , ANNA BAZZICALUPO, JOSKE RUYTINX, LOTUS LOFGREN, THOMAS BRUNS, SARA BRANCO, BRIAN LOONEY, DAI HIROSE, LEHO TEDERSOO, URSULA PEINTNER, J ALEJANDRO ROJAS, HUI-LING LIAO, JONATHAN PLETT, IAN ANDERSON, ANNA LIPZEN, ALAN KUO, KERRIE BARRY, IGOR GRIGORIEV, JASON D. HOEKSEMA, NHU H. NGUYEN, PETER G. KENNEDY, RYTAS VILGALYS
Department of Ecology and Evolutionary Biology, University of Michigan, 1105 N University Ave, Ann Arbor, MI 48109

Human colonization since the 19th century has led to global spread of pines and pine forests to the Southern Hemisphere, well beyond their original northern boreal distribution. Although the introduction of pines is documented through historical records, little is known about the introduction history of their ectomycorrhizal fungi, which are critical symbionts for the survival and invasion of pines. Population genomic analyses of 208 S. luteu s individuals across the native and introduced ranges showed that all introductions originated from Europe, likely mediated by human activities along with pine introductions. With the exception of North America, all introduced populations were genetically differentiated from the Europe population, experienced decreased genetic diversity, reduced numbers of mating types, and various magnitudes of population expansion in different introduced populations, which can be linked to different forestry practices. Genetic variation within the native European population followed isolation by distance, but not in the introduced range, highlighting the disparity in dispersal ecology and the history of native versus exotic habitats. Several genes associated with regulatory functions showed shared signatures of selections among multiple introduced populations, implying their important roles in adaptation to exotic environments.