Phylogenetics and diversification of morning glories (tribe Ipomoeeae, Convolvulaceae) based on whole plastome sequences
- Source:
- American journal of botany 2014 v.101 no.1 pp. 92-103
- ISSN:
- 0002-9122
- Subject:
- Ipomoea, chloroplast DNA, chloroplasts, data collection, genes, molecular systematics, monophyly, nucleotide sequences, plant taxonomy, pollen
- Abstract:
- Phylogenetic studies have demonstrated the largest morning glory genus, Ipomoea, is not monophyletic, and nine other segregate genera are derived from within Ipomoea. Therefore, systematic research is focused on the monophyletic tribe Ipomoeeae (c. 650-900 species). We used whole plastid genomes to infer relationships among exemplar species distributed across Ipomoeeae. Whole plastomes were sequenced, assembled and annotated for twenty-eight morning glory species, representing major Ipomoeeae lineages. Phylogenies were estimated for twenty-eight species sequenced here and one published plastome using alignments of: (a) eighty-two chloroplast genes and (b) whole plastomes. In addition, divergence times were estimated to date key divergence events within the Ipomoeeae. Two nodes were calibrated with fossil pollen for molecular dating analyses. Phylogenies estimated from the two plastome datasets had identical topologies. Phylogenetic results are generally consistent with prior phylogenetic analyses of morning glories. Two major clades, previously named Astripomoeinae and Argyreiinae, are well-supported. There also is support for the monophyly of Ipomoea subgenus Quamoclit. Higher-level relationships with weak support in previous analyses were recovered in this analysis with strong support. Results from the molecular dating analysis suggest a middle Eocene divergence time for the Ipomoeeae. Furthermore, the Argyreiinae clade was found to have diversified before the Astripomoeinae; however, error bars overlap between divergence time estimates of these two clades. Phylogenetic results presented here provide greater confidence in relationships among major lineages of the Ipomoeeae, and divergence time estimation results provide a temporal context for the diversification of this fascinating group of angiosperms.
- Agid:
- 58757
- Handle:
- 10113/58757
- https://doi.org/10.3732/ajb.1300207