Meerow, Alan W. , Noblick, Larry R. , Borrone, James W. , Couvreur, Thomas , Mauro-Herrera, Margarita , Hahn, William James , Kuhn, David N. , Nakamura, Kyoko , Oleas, Nora , Schnell, Raymond J. .
Combined phylogenetic analysis of seven WRKY transcription factor loci across the palm subtribe Attaleinae (Areceaceae, Cocoseae) confirms the American roots of the coconut.
The WRKY gene family of transcription factors is involved in several diverse pathways and includes components of plant-specific, ancient regulatory networks. The family exhibits very low levels of paralogy in rice. WRKY genes contain one or two highly conserved DNA binding domains interrupted by an intron. We designed primers from seven putatively single copy WRKY loci isolated from Cocos nucifera and found that they could successfully amplify DNA from all genera of the subtribe Attaleinae sampled as well as from three outgroup taxa representing subtribes Bactridinae and Elaeidinae. Maximum parsimony, maximum likelihood, and Bayesian analysis of the combined data matrix all produce congruent and well-resolved topologies. In contrast to plastid sequence based phylogenies of the subtribe, Syagrus (inclusive of Lytocaryum) is resolved as monophyletic, and is the sister genus to Cocos nucifera with strong bootstrap support (BP), confirming American ancestry for the genus Cocos. Attalea and Butia are also consistently resolved as monophyletic, and Jubaea is robustly sister to Butia. Allagoptera, Parajubaea and Polyandrococos form a clade with 95% BP that is supported by leaf anatomical evidence. Subclades within Syagrus and Attalea are often congruent with morphological and/or biogeographic data. Age calibration of the likelihood tree estimates the divergence of Cocos from Syagrus as 27 MYBP. Establishment of the two major clades of American Attaleinae appears to have occurred in the Oligocene (ca. 30 MYBP), with basal cladogenesis at the Oligocene-Miocene boundary. Much of the subsequent diversification in the Attaleinae can be attributed to the Andean uplift from late Miocene through the Pliocene, and Pleistocene fluctuations in the extent and location of rain forest and seasonally dry climates in South America. WRKY loci show promise for investigating phylogenetic relationships within the palm family, and our primers should be tested in other tribes of the subfamily Arecoideae.
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1 - U. S. Dept. of Agriculture, Agricultural Research Service, National Germplasm Repository, 13601 Old Cutler Rd., Miami, FL, 33158, United States
2 - Montgomery Botanical Center, 11901 Old Cutler Road, Miami, Florida, 33156, USA
3 - Oklahoma State University, Department of Botany, 104 Life Sciences East , Stillwater, OK, 74078-3013, USA
4 - The New York Botanical Garden, 200 Southern Blvd, Bronx, NY, 10458, USA
5 - Georgetown University, Georgetown College, 108 White-Gravenor, Po Box 571003, Washington, DC, 20057-1003, USA
6 - Florida International University, Deparment of Biological Sciences, 11200 SW 8th St., Miami, Florida, 33199, USA
single copy nuclear genes
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood A/Snowbird Center
Date: Monday, July 27th, 2009
Time: 4:45 PM