Host species identity, site and time drive temperate tree phyllosphere bacterial community structure.
The increasing awareness of the role of phyllosphere microbial communities in plant health calls for a greater understanding of their structure and dynamics in natural ecosystems. Since most knowledge of tree phyllosphere bacterial communities has been gathered in tropical forests, our goal was to characterize the community structure and assembly dynamics of phyllosphere epiphytic bacterial communities in temperate forests in Quebec, Canada. We targeted five dominant tree species: Acer saccharum, Acer rubrum, Betula papyrifera, Abies balsamea, and Picea glauca. We collected 180 samples of phyllosphere communities on these species at four natural forest sites, three times during the growing season.



Host functional traits (i.e., wood density, leaf nitrogen content) and climate variables (summer mean temperature and precipitation) were strongly correlated with community structure. We highlight three key findings: (1) temperate tree species share a "core microbiome"; (2) significant evolutionary associations exist between groups of bacteria and host species; and (3) a greater part of the variation in phyllosphere bacterial community assembly is explained by host species identity (27 %) and species-site interaction (14 %), than by site (11 %) or time (1 %).



We demonstrated that host species identity is a stronger driver of temperate tree phyllosphere bacterial communities than site or time. Our results suggest avenues for future studies on the influence of host functional traits on phyllosphere community functional biogeography across terrestrial biomes.
Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montréal, H3C 3P8, Québec, Canada. isabelle.laforest.lapointe@gmail.com.|Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montréal, H3C 3P8, Québec, Canada. isabelle.laforest.lapointe@gmail.com.
Isabelle
0000-0003-3630-9475
I
Laforest-Lapointe
Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montréal, H3C 3P8, Québec, Canada.|Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montréal, H3C 3P8, Québec, Canada.|Institut des Sciences de la Forêt tempérée, Université du Québec en Outaouais, Ripon, J0V 1V0, Québec, Canada.
Christian
C
Messier
Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montréal, H3C 3P8, Québec, Canada.|Centre d'étude de la forêt, Université du Québec à Montréal, C.P. 8888, Succ. Centre-Ville, Montréal, H3C 3P8, Québec, Canada.
Steven W
SW
Kembel
D028202:Abies / Q000382:microbiology; D031002:Acer / Q000382:microbiology*; D001419:Bacteria / Q000145:classification*; D029662:Betula / Q000382:microbiology*; D044822:Biodiversity; D058507:Host Specificity; D010802:Phylogeny; D028222:Picea / Q000382:microbiology; D028201:Pinaceae / Q000382:microbiology*; D011792:Quebec
Bacteria; Microbiome; Phyllosphere; Plant-bacteria interaction; Temperate forest