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  1. Premise

    Apocynaceae is the 10th largest flowering plant family and a focus for study of plant–insect interactions, especially as mediated by secondary metabolites. However, it has few genomic resources relative to its size. Target capture sequencing is a powerful approach for genome reduction that facilitates studies requiring data from the nuclear genome in non‐model taxa, such as Apocynaceae.

    Methods

    Transcriptomes were used to design probes for targeted sequencing of putatively single‐copy nuclear genes across Apocynaceae. The sequences obtained were used to assess the success of the probe design, the intrageneric and intraspecific variation in the targeted genes, and the utility of the genes for inferring phylogeny.

    Results

    From 853 candidate nuclear genes, 835 were consistently recovered in single copy and were variable enough for phylogenomics. The inferred gene trees were useful for coalescent‐based species tree analysis, which showed all subfamilies of Apocynaceae as monophyletic, while also resolving relationships among species within the genusApocynum. Intraspecific comparison ofElytropus chilensisindividuals revealed numerous single‐nucleotide polymorphisms with potential for use in population‐level studies.

    Discussion

    Community use of this Hyb‐Seq probe set will facilitate and promote progress in the study of Apocynaceae across scales from population genomics to phylogenomics.

     
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  2. Premise

    Comprising five families that vastly differ in species richness—ranging from Gelsemiaceae with 13 species to the Rubiaceae with 13,775 species—members of the Gentianales are often among the most species‐rich and abundant plants in tropical forests. Despite considerable phylogenetic work within particular families and genera, several alternative topologies for family‐level relationships within Gentianales have been presented in previous studies.

    Methods

    Here we present a phylogenomic analysis based on nuclear genes targeted by the Angiosperms353 probe set for approximately 150 species, representing all families and approximately 85% of the formally recognized tribes. We were able to retrieve partial plastomes from off‐target reads for most taxa and infer phylogenetic trees for comparison with the nuclear‐derived trees.

    Results

    We recovered high support for over 80% of all nodes. The plastid and nuclear data are largely in agreement, except for some weakly to moderately supported relationships. We discuss the implications of our results for the order’s classification, highlighting points of increased support for previously uncertain relationships. Rubiaceae is sister to a clade comprising (Gentianaceae + Gelsemiaceae) + (Apocynaceae + Loganiaceae).

    Conclusions

    The higher‐level phylogenetic relationships within Gentianales are confidently resolved. In contrast to recent studies, our results support the division of Rubiaceae into two subfamilies: Cinchonoideae and Rubioideae. We do not formally recognize Coptosapelteae and Luculieae within any particular subfamily but treat them as incertae sedis. Our framework paves the way for further work on the phylogenetics, biogeography, morphological evolution, and macroecology of this important group of flowering plants.

     
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