Message - 7th IAL Symposium

Lichen: from genome to ecosystem in a changing world
3A: Molecular phylogenetics
(3A-O1) Submission ID: IAL0273-00001
THE DATING OF FUNGI AND PLANTS
Lutzoni F. 1 , Magallon S. 2 , Nowak M. 1 , Alfaro M. 3 , Mcdonald T. 1 , Miadlikowska J. 1 , Reeb V. 1
1 Department of Biology, Duke University, Durham, United States
2 Instituto de Biologia, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
3 Department of Ecology and Evolutionary Biology, University of California, Los Angeles, United States
The lichen symbiosis is one of many successful interactions between fungi and plants. The omnipresence
of these interdependent heterotrophic-autotrophic associations at spatial and temporal scales, and ranging
from mutualism to parasitism, suggests a strongly linked coevolution of these two kingdoms. If true, major
adaptive radiations of plants and fungi should be mostly synchronized. In this study we have estimated divergence
time of the fungi and land plants independently and inferred the occurrence of drastic shifts in rates of
diversification across both chronograms. The combination of both analytical results enabled us to determine the
synchronicity of these shifts in species diversification that likely occurred during the evolution of fungi and plants.
Lichen-forming ascomycetes originated during one of the most spectacular adaptive radiations of the fungi, and
of the plant kingdom. The origin of ascolichens is more recent than previously expected within the context of
plant evolution, and is associated with the origin and radiation of hyperdiverse endophytic and endolichenic fungi
interacting symbiotically with photosynthetic cells of plants as well as photoautotrophic prokaryotic and eukaryotic
cells (photobionts) found in lichens. The origin of these Leotiomyceta fungi interacting with photosynthetic
cells of plants are associated with the acquisition of an ammonium transporter/ammonia permease (AMTP) gene
from hyperthermophilic chemolithoautotrophic prokaryotes via horizontal gene transfer. Balanced transport of
nitrogen among lichen symbionts could be essential for the establishment and maintenance of this symbiosis,
especially in nitrogen limiting environments.
3A-O
(3A-O2) Submission ID: IAL0174-00001
DIVERSIFICATION OF LICHEN-FORMING ASCOMYCETES
Nelsen M. P. 1 , Lücking R. 2 , Lumbsch H. 2 , Ree R. 2
1 Committee on Evolutionary Biology, Department of Botany, University of Chicago, Field Museum,
Chicago, Illinois, United States
2 Department of Botany, The Field Museum, Chicago, United States
The disparity in species richness across fungal lineages is striking. Within the fungal class Lecanoromycetes
(Ascomycota), this unevenness is especially pronounced, with the number of species per family ranging
from under 15 to nearly 2,500. Here potential explanations for this imbalance, initially focusing on clade age and
diversification rate, are explored. Clade age showed little correlation with clade richness, while a strong correlation
was observed between net diversification rate and clade richness. A number of families, such as Parmeliaceae
and Cladoniaceae, were identified as having exceptionally high diversification rates, while a number of
families with low species richness, such as Gypsoplacaceae and Miltideaceae had exceptionally low diversification
rates. Finally, we attempt to identify potential sources of variation in diversification rates across Lecanoromycetes.
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