HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (53) Citing Articles via Google Scholar Google Scholar Articles by Kim, S. Articles by Soltis, D. E. Search for Related Content PubMed Articles by Kim, S. Articles by Soltis, D. E. Agricola Articles by Kim, S. Articles by Soltis, D. E.

Phylogeny and diversification of B-function MADS-box genes in angiosperms: evolutionary and functional implications of a 260-million-year-old duplication¹

²Department of Botany, University of Florida, Gainesville, Florida 32611 USA; ³The Natural History Museums and Botanical Garden, University of Oslo, P.O. Box 1172 Blindern, NO-0318 Oslo, Norway; ⁴Molekylärsystematiska laboratoriet, Naturhistoriska riksmuseet, Box 50007, SE-104 05 Stockholm, Sweden; ⁵Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611 USA

B-function MADS-box genes play crucial roles in floral development in model angiosperms. We reconstructed the structural and functional implications of B-function gene phylogeny in the earliest extant flowering plants based on analyses that include 25 new AP3 and PI sequences representing critical lineages of the basalmost angiosperms: Amborella, Nuphar (Nymphaeaceae), and Illicium (Austrobaileyales). The ancestral size of exon 5 in PI-homologues is 42 bp, typical of exon 5 in other plant MADS-box genes. This 42-bp length is found in PI-homologues from Amborella and Nymphaeaceae, successive sisters to all other angiosperms. Following these basalmost branches, a deletion occurred in exon 5, yielding a length of 30 bp, a condition that unites all other angiosperms. Several shared amino acid strings, including a prominent "DEAER" motif, are present in the AP3- and PI-homologues of Amborella. These may be ancestral motifs that were present before the duplication that yielded the AP3 and PI lineages and subsequently were modified after the divergence of Amborella. Other structural features were identified, including a motif that unites the previously described TM6 clade and a deletion in AP3-homologues that unites all Magnoliales. Phylogenetic analyses of AP3- and PI-homologues yielded gene trees that generally track organismal phylogeny as inferred by multigene data sets. With both AP3 and PI amino acid sequences, Amborella and Nymphaeaceae are sister to all other angiosperms. Using nonparametric rate smoothing (NPRS), we estimated that the duplication that produced the AP3 and PI lineages occurred approximately 260 mya (231–290). This places the duplication after the split between extant gymnosperms and angiosperms, but well before the oldest angiosperm fossils. A striking similarity in the multimer-signalling C domains of the Amborella proteins suggests the potential for the formation of unique transcription-factor complexes. The earliest angiosperms may have been biochemically flexible in their B function and "tinkered" with floral organ identity.

Key Words: Amborella • AP3 • B-class • basal angiosperms • MADS • PI

This article has been cited by other articles:

				D. E. Soltis, C. D. Bell, S. Kim, and P. S. Soltis Origin and Early Evolution of Angiosperms Ann. N.Y. Acad. Sci., June 1, 2008; 1133(1): 3 - 25. [Abstract] [Full Text] [PDF]

				L. P. Ronse De Craene Are Petals Sterile Stamens or Bracts? The Origin and Evolution of Petals in the Core Eudicots Ann. Bot., September 1, 2007; 100(3): 621 - 630. [Abstract] [Full Text] [PDF]

				T. R. Meagher Linking the Evolution of Gender Variation to Floral Development Ann. Bot., August 1, 2007; 100(2): 165 - 176. [Abstract] [Full Text] [PDF]

				D. E. Soltis, A. S. Chanderbali, S. Kim, M. Buzgo, and P. S. Soltis The ABC Model and its Applicability to Basal Angiosperms Ann. Bot., August 1, 2007; 100(2): 155 - 163. [Abstract] [Full Text] [PDF]

				E. M. Kramer, L. Holappa, B. Gould, M. A. Jaramillo, D. Setnikov, and P. M. Santiago Elaboration of B Gene Function to Include the Identity of Novel Floral Organs in the Lower Eudicot Aquilegia PLANT CELL, March 1, 2007; 19(3): 750 - 766. [Abstract] [Full Text] [PDF]

				T. Hernandez-Hernandez, L. P. Martinez-Castilla, and E. R. Alvarez-Buylla Functional Diversification of B MADS-Box Homeotic Regulators of Flower Development: Adaptive Evolution in Protein-Protein Interaction Domains after Major Gene Duplication Events Mol. Biol. Evol., February 1, 2007; 24(2): 465 - 481. [Abstract] [Full Text] [PDF]

				R. M. Bateman, J. Hilton, and P. J. Rudall Morphological and molecular phylogenetic context of the angiosperms: contrasting the 'top-down' and 'bottom-up' approaches used to infer the likely characteristics of the first flowers J. Exp. Bot., October 1, 2006; 57(13): 3471 - 3503. [Abstract] [Full Text] [PDF]

				A. S. Rijpkema, S. Royaert, J. Zethof, G. van der Weerden, T. Gerats, and M. Vandenbussche Analysis of the Petunia TM6 MADS Box Gene Reveals Functional Divergence within the DEF/AP3 Lineage PLANT CELL, August 1, 2006; 18(8): 1819 - 1832. [Abstract] [Full Text] [PDF]

				G. de Martino, I. Pan, E. Emmanuel, A. Levy, and V. F. Irish Functional Analyses of Two Tomato APETALA3 Genes Demonstrate Diversification in Their Roles in Regulating Floral Development PLANT CELL, August 1, 2006; 18(8): 1833 - 1845. [Abstract] [Full Text] [PDF]

				D. G. Howarth and M. J. Donoghue Phylogenetic analysis of the "ECE" (CYC/TB1) clade reveals duplications predating the core eudicots PNAS, June 13, 2006; 103(24): 9101 - 9106. [Abstract] [Full Text] [PDF]

				L. Cui, P. K. Wall, J. H. Leebens-Mack, B. G. Lindsay, D. E. Soltis, J. J. Doyle, P. S. Soltis, J. E. Carlson, K. Arumuganathan, A. Barakat, et al. Widespread genome duplications throughout the history of flowering plants Genome Res., June 1, 2006; 16(6): 738 - 749. [Abstract] [Full Text] [PDF]

				S. Kim, P. S. Soltis, K. Wall, and D. E. Soltis Phylogeny and Domain Evolution in the APETALA2-like Gene Family Mol. Biol. Evol., January 1, 2006; 23(1): 107 - 120. [Abstract] [Full Text] [PDF]

				J. Leebens-Mack, L. A. Raubeson, L. Cui, J. V. Kuehl, M. H. Fourcade, T. W. Chumley, J. L. Boore, R. K. Jansen, and C. W. dePamphilis Identifying the Basal Angiosperm Node in Chloroplast Genome Phylogenies: Sampling One's Way Out of the Felsenstein Zone Mol. Biol. Evol., October 1, 2005; 22(10): 1948 - 1963. [Abstract] [Full Text] [PDF]

				L. M. Zahn, J. Leebens-Mack, C. W. dePamphilis, H. Ma, and G. Theissen To B or Not to B a Flower: The Role of DEFICIENS and GLOBOSA Orthologs in the Evolution of the Angiosperms J. Hered., May 1, 2005; 96(3): 225 - 240. [Abstract] [Full Text] [PDF]

				L. M. Zahn, H. Kong, J. H. Leebens-Mack, S. Kim, P. S. Soltis, L. L. Landherr, D. E. Soltis, C. W. dePamphilis, and H. Ma The Evolution of the SEPALLATA Subfamily of MADS-Box Genes: A Preangiosperm Origin With Multiple Duplications Throughout Angiosperm History Genetics, April 1, 2005; 169(4): 2209 - 2223. [Abstract] [Full Text] [PDF]