Plant development and evolution: Lessons learned from candidate genes
Sliwinski, Marek K. , Yoon, Ho-Sung , Baum, David A. .
A transgenic test of parallelism in plant architectural evolution.
The evolution of plant architecture within the Brassicaceae provides an opportunity to test whether the same (parallelism) or distinct (convergence) genetic and developmental mechanisms were involved in the independent origins of a derived trait. Three species Ionopsidium acaule (Iac), Idahoa scapigera (Isc), and Leavenworthia crassa (Lcr), represent three independent evolutions of a rosette flowering morphology from an ancestral inflorescence flowering condition, represented by Arabidopsis thaliana (Ath). Rosette flowering plants produce flowers on elongated pedicels that arise from the axils of rosette leaves whereas inflorescence flowering plants produce flowers on an elongated portion of leafless stem (the inflorescence). To determine whether each origin of rosette flowering involved similar genetic changes, we moved a candidate gene, LFY, from each rosette flowering species into A. thaliana lfy mutants by interspecific transformation. A variety of phenotypes arose providing evidence against a strict parallelism hypothesis. IacLFY rescued A. thaliana lfy plants to the wild type plant architecture. IscLFY1, one of two LFY genes in I. scapigera, restored wildtype floral organs but plants often produced novel aerial rosettes, clusters of bracteate flowers without internode elongation. LcrLFY also rescued floral defects but produced modified inflorescences with terminal flowers. These results suggest that LFY played different roles in the evolution of rosette-flowering in two of the studied species, I. scapigera and L. crassa, and that genetic changes at the LFY locus coevolved with different genetic partners to generate rosette-flowering in each case.
1 - University of Wisconsin-Madison, Botany, 430 Lincoln Drive, Madison, Wisconsin, 53706-1381, USA
2 - Kyungpook National University, Institute of Agricultural Science and Technology, Daegu, 702-701, South Korea
Presentation Type: Symposium
Location: Ballroom 1 (Cliff Lodge)
Date: Wednesday, August 4th, 2004
Time: 8:15 AM