Comparative transcriptomics reveals divergence in pathogen response gene families amongst 20 forest tree species

Forest trees provide critical ecosystem services for humanity that are under threat due to ongoing global change. Measuring and characterizing genetic diversity is key to understanding adaptive potential and developing strategies to mitigate negative consequences arising from climate change. In the area of forest genetic diversity, genetic divergence caused by large-scale changes at the chromosomal level has been largely understudied. In this study, we used the RNA-seq data of twenty co-occurring forest tree species from genera including Acer, Alnus, Amelanchier, Betula, Cornus, Corylus, Dirca, Fraxinus, Ostrya, Populus, Prunus, Quercus, Ribes, Tilia, and Ulmus sampled from Upper Peninsula of Michigan. These data were used to infer the origin and maintenance of gene family variation, species divergence time, as well as gene family expansion and contraction. We identified a signal of common whole genome duplication events shared by core eudicots. We also found rapid evolution, namely fas..., Leaves of each of twenty forest species were sampled in August 2021, at the University of Notre Dame Environmental Research Center (UNDERC) near Land O' Lakes, Wisconsin, U.S.A. (Fig. 1). The UNDERC site is located at latitude: 46.23391, longitude: -89.537254, and encompasses approximately ~8,000 acres of mixed deciduous forest on both sides of the state line between Wisconsin and Michigan’s upper peninsula. The twenty species used in this study are dominant components of the woody vegetation at the site and are: Acer rubrum (red maple), Acer saccharum (sugar maple), Acer spicatum (mountain maple), Alnus incana (Gary alder), Amelanchier laevis (smooth serviceberry), Betula alleghaniensis (yellow birch), Betula papyrifera (paper birch), Cornus alternifolia (pagoda dogwood), Corylus cornuta (beaked hazelnut), Dirca palustris (Eastern leatherwood), Fraxinus nigra (black ash), Ostrya virginiana (American hophornbeam), Populus grandidentata (bigtooth aspen), Populus tremuloides (quaking aspe..., ,