| Abstract Detail
Developmental and Structural Section Sridaran, Sankar [1], Stonebloom, Solomon [1], Bartlett, Madelaine [2], Specht, Chelsea [1]. The labellum of Costus (Zingiberales) and the ABC model of floral development. The ABC model of floral development proposes that three classes of organ identity genes are required for floral patterning: A class gene expression alone specifies sepal identity, A and B genes expressed together specify petal identity, B and C class gene expression confers stamen identity and C gene expression alone specifies the organ identity of the carpel whorl. The expression patterns of all but one of the ABC genes mirror their domains of activity. Although this model has been well established and expanded upon in model organisms such as Arabidopsis thaliana, little is known about how the ABC model of floral development can be applied to non-model system species, especially those with floral morphologies that suggest alterations in organ identity. Members of the monocot family Costaceae possess a derived petaloid floral organ - the labellum – in the stamen whorl. The labellum is formed by the fusion of five primordia that develop from the two stamen whorls – two from the inner whorl, three from the outer whorl. One single stamen of the inner whorl remains fertile. Co-expression of AGAMOUS (C class), APETALA3 and PISTILLATA (B class) is required to confer stamen identity in Arabidopsis. Presumably this canonical pattern of gene expression has been modified to produce the labellum of Costus. Using phylogenetic analysis to recover putative orthologs of B and C class genes from species throughout the Zingiberales, we present data on the expression pattern of these genes in developing flowers of Costus dubius using epi-illuminescence microscopy linked to in situ hybridization. This is the first in a number of studies aimed at investigating how evolutionarily conserved genes may be adapted and recruited through the course of evolution to generate morphological novelties. Log in to add this item to your schedule
1 - UC Berkeley, Plant and Microbial Biology, 111 Koshland Hall, Berkeley, California, 94720-3102, USA 2 - University of California, Berkeley, Plant and Microbial Biology, 111 Koshland Hall, Berkeley, CA, 94720-3102, United States
Keywords: MADs box genes Costus Zingiberales Floral development floral morphology developmental evolution.
Presentation Type: Oral Paper:Papers for Sections Session: CP26 Location: Boulevard C/Hilton Date: Tuesday, July 10th, 2007 Time: 9:15 AM Number: CP26006 Abstract ID:1178 |