Biomedical subjects

Marion Vinauger-Douard

Publications and source records attributed to Marion Vinauger-Douard.

3 recordsLinked to original sources

PubMed2006

An evolutionary perspective on the regulation of carpel development.

The carpel, or female reproductive organ enclosing the ovules, is one of the major evolutionary innovations of the flowering plants. The control of carpel development has been intensively studied in the model eudicot species Arabidopsis thaliana. This review traces the evolutionary history of genes involved in carpel development by surveying orthologous genes in taxa whose lineages separated from that of A. thaliana at different levels of the phylogenetic tree of the seed plants. Some aspects of the control of female reproductive development are conserved between the flowering plants and their sister group, the gymnosperms, indicating the presence of these in the common ancestor of the extant seeds plants, some 300 million years ago. Gene duplications that took place in the pre-angiosperm lineage, before the evolution of the first flowering plants, provided novel gene clades of potential importance for the origin of the carpel. Subsequent to the appearance of the first flowering plants, further gene duplications have led to sub-functionalization events, in which pre-existing reproductive functions were shared between paralogous gene clades. In some cases, fluidity in gene function is evident, leading to similar functions in carpel development being controlled by non-orthologous genes in different taxa. In other cases, gene duplication events have created sequences that evolved novel functions by the process of neo-functionalization, thereby generating biodiversity in carpel and fruit structures.

Biological Evolution↗

PubMed2005

Evidence that CRABS CLAW and TOUSLED have conserved their roles in carpel development since the ancestor of the extant angiosperms.

The carpel is the female reproductive organ specific to flowering plants. We aim to define the genes that controlled carpel development in the common ancestor of this group as a step toward determining the molecular events that were responsible for the evolution of the carpel. CRABS CLAW (CRC) and TOUSLED (TSL) control important aspects of carpel development in the model plant, Arabidopsis thaliana. The basal angiosperm species Amborella trichopoda and Cabomba aquatica very likely represent the two most early diverging groups of flowering plants. We have identified putative orthologues of CRC and TSL from A. trichopoda and C. aquatica, respectively. We demonstrate the expression patterns of these genes in carpels to be very highly conserved, both spatially and temporally, with those of their Arabidopsis orthologues. We argue that CRC and TSL in Arabidopsis are likely to have conserved their respective roles in carpel development since the common ancestor of the living flowering plants. We conclude that a divergent role shown for the CRC orthologue in rice, DROOPING LEAF, most probably arose specifically in the monocot lineage. We show that, in addition to its expression in carpels, the TSL orthologue of C. aquatica is expressed in tissues that contribute to buoyancy and argue that its role in these tissues may have arisen later than its role in carpel development.

Arabidopsis↗

PubMed2003

The identification of candidate genes for a reverse genetic analysis of development and function in the Arabidopsis gynoecium.

The screening for mutants and their subsequent molecular analysis has permitted the identification of a number of genes of Arabidopsis involved in the development and functions of the gynoecium. However, these processes remain far from completely understood. It is clear that in many cases, genetic redundancy and other factors can limit the efficiency of classical mutant screening. We have taken the alternative approach of a reverse genetic analysis of gene function in the Arabidopsis gynoecium. A high-throughput fluorescent differential display screen performed between two Arabidopsis floral homeotic mutants has permitted the identification of a number of genes that are specifically or preferentially expressed in the gynoecium. Here, we present the results of this screen and a detailed characterization of the expression profiles of the genes identified. Our expression analysis makes novel use of several Arabidopsis floral homeotic mutants to provide floral organ-specific gene expression profiles. The results of these studies permit the efficient targeting of effort into a functional analysis of gynoecium-expressed genes.

Arabidopsis↗