Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Whipple, Clinton [1], Guo, Jinyan [2], Thayer, Rachel [3].

Bracts, Branches and Boundaries: signaling centers and the evolution of inflorescence architecture in the grasses.

Bracts are the leaves produced after the transition from vegetative to reproductive development, and generally subtend flowers or inflorescence branches. Bract leaves are frequently reduced compared to vegetative leaves, and in some cases are entirely suppressed. Bract suppression evolved multiple times in distinct lineages, including the Brassicaceae and Poaceae, making it possible to investigate the genetic control of convergent morphologies. Our investigation of genes regulating bract suppression in maize (Zea mays ssp. mays) indicates that bract suppression is regulated by a complex network of genes that have pleiotropic effects on inflorescence branching as well. Genetic and molecular evidence from these maize bract mutants suggests that the origin of bract suppression involved the recruitment of boundary domain genes, and that the suppressed bract is acting as a signaling center to regulate branching of its axillary inflorescence branch meristem. Additional genetic evidence suggests that the bract signaling center communicates with an additional center adaxial to the branch meristem, which is likely specific to a grass tribe (Andropogoneae) that has distinct determinate and indeterminate lateral branches. Thus two distinct signaling centers coordinate branch meristem determinacy in the Andropogoneae, and bract suppression can be interpreted as a developmental constraint that evolved as a consequence of novel signaling centers that coordinate meristem determinacy.

1 - Brigham Young University, Biology, 4102 Life Science Building, Provo, UT, 84602, USA
2 - Brigham Young University, Biology, 4102 Life Science Building, Provo, UT, 84062
3 - Brigham Young University, Biology, 4102 Life Science Building, Provo, UT, 84602

Keywords:
maize
inflorescence architecture
bract.

Presentation Type: Oral Paper
Session: 2, Evolution and Development
Location: 200/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 11:00 AM
Number: 2012
Abstract ID:721
Candidate for Awards:None