Oct. 24-26, 2009, Yingjie Overseas Exchange Center, Peking University, Beijing, China中文版

Evolution of the regulatory network for floral development

Hongzhi Kong

State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing, 100093, China

Abstract

The development of a flower is genetically controlled by a network formed by numerous regulatory genes (nodes) and the complex interactions (lines) among them. To understand the mechanisms that underlie the origin and diversification of the flower, we have investigated the evolution of the regulatory genes and the interactions among them. We found that regulatory genes occupying different positions in the network had experienced dramatically different evolutionary histories. In some cases (especially in floral MADS-box genes), limited rounds of gene duplication events have occurred, and genes with novel structures and functions have been generated at the bases of the major groups such as angiosperms, core eudicots, and the grass family, etc. This suggests that the evolution of these groups were not random, and that duplication and subsequent diversification of some regulatory genes have contributed to the morphological innovations in floral structure. In other cases, however, no such correlation was observed, although multiple gene duplication events were also detected. Because of floral MADS-box genes encode transcription factors that regulate the expression of their downstream genes by forming (homo-/hetero-)dimers and quaternary complexes, we have also investigated the evolution of the protein-protein interactions (PPIs) among these genes. We found that the PPIs among most floral MADS-box genes have been highly conserved in angiosperm evolution, with most parts being extremely stable and only a small fraction being variable. The evolutionarily conservative PPIs may have played critical roles for the establishment of the basic structures of the flower, and may have experienced co-evolution to maintain their functions. The evolutionarily variable PPIs, on the contrary, may have played minor roles in floral development and contributed to the variation in floral features.

 

Hongzhi Kong

Institute of Botany, CAS, China

Biography

Professor Hongzhi Kong was born in 1973. He graduated from Northwest University in 1995 and obtained his Ph.D. degree in Institute of Botany, the Chinese Academy of Sciences in 2000. During 2002-2004, he worked for the Pennsylvania State University as a Visiting Postdoctoral Scholar. He became a full professor in Institute of Botany, the Chinese Academy of Sciences in 2006. Professor Hongzhi Kong is broadly interested in the evolution of the flower. He and his research group use morphological, phylogenetic, molecular, developmental, genomic and bioinformatic approaches to study how flowers have originated and diversified. The final goal of these “Evo-Devo” studies is to elucidate how changes in genomic sequences have led to evolutionary novelties in phenotype, and how diversity in floral characters has been generated and retained during plant evolution. Research projects in Kong’s group cover a diverse set of topics, including: 1) evolution of the regulatory network for floral development; 2) molecular mechanisms that underlie the diversification of flowers and floral organs; and 3) generation and diversification of duplicate genes. In the past five years, Kong’s group has made substantial progresses in several projects and published research articles in PNAS, Molecular Biology and Evolution, The Plant Journal, Molecular Phylogenetics and Evolution, and Genetics.