Arias, Tatiana , Pires, Joseph .
A phylogenomic approach to resolving the evolutionary relationships among Brassica crops and their wild relatives (Brassiceae, Brassicaceae).
Brassica crops and their wild relatives (tribe Brassiceae) belong to the mustard family(Brassicaceae) and contain more agriculturally and horticulturally important crops than any other family of flowering plants. They are native to Western Europe, the Mediterranean, and temperate regions of Asia. Mustard plants are most diverse in the Mediterranean region where their evolutionary history has been shaped by geological activity, climate change, and human activity. The Brassiceae is a monophyletic group with 54 genera and approximately 240 species. Relationships among, and circumscription of, its subtribes have been a matter of debate for many years. This research focuses on recovering a robust phylogeny for the tribe using traditional phylogenetic and new phylogenomic approaches. First, we sequenced four highly variable and phylogenetically informative chloroplast intergenic regions for 120 species. Our phylogeny recovers seven well-supported clades: Nigra, Crambe, Oleracea, Cakile, Vella,Zilla and a new African clade comprised of genera that have not been previously sampled. Relationships among these seven main clades are weakly supported in this phylogeny, and there is a lack of resolution among the seven subtribes. The monophyly of the tribe is confirmed with Vella and Zilla as the outer clades.This phylogeny challenges the evolutionary relationships and phylogenetic position of several genera previously defined using classical taxonomy. Second,we reconstructed a whole chloroplast and whole mitochondrial phylogeny for 26 taxa representing eight main clades in the tribe. The whole chloroplast phylogeny recovered eight clades with 100% bootstrap values for most nodes inthe phylogeny. The Oleracea clade is sister to Savignia, and this clade is sister to Crambe + Nigra. Cakile is sister to these four clades followed by the sister group Vella. The outer group sister to all the other clades in the tribe is Zilla. These results are complementary to the four-chloroplast markers phylogeny. The whole mitochondrial phylogeny recovered two of the seven main clades identified with the whole chloroplast phylogeny, Oleracea and Cakile.
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1 - University of Missouri, Biological Sciences, 311 Life Sciences Center, Columbia, MO, 65211, USA
2 - University Of Missouri, 371 B Life Sciences Center, 1201 Rollins Street, Columbia, MO, 65211-7310, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell B/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 11:15 AM