Are CYCLOIDEA-like genes involved in the control of floral zygomorphy in Schizanthus wisetonensis?

• Main Author: Coenen, Karine
• Published: University of Edinburgh 2004
• Subjects: 581.35
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.643308

In <i>Antirrhinum majus </i>(Scrophulariaceae), floral dorso-ventral asymmetry (monosymmetry) is controlled by two genes belonging to the TCP gene family, <i>CYCLOIDEA </i>and <i>DICHOTOMA. </i>My<i> </i>project was to investigate if putative orthologs of <i>CYC </i>and <i>DICH </i>have a conserved role in <i>Schizanthus wisotonensis </i>(Solanaceae), a species also bearing monosymmetrical flowers. To do so, TCP genes from <i>S. wisotonensis </i>were isolated and their expression pattern was characterised in both a wild type and a mutant plant with decreased dorso-ventral asymmetry. In the first chapter of results, a thorough morphological description of floral development in <i>S. wisotonensis </i>was carried out using the support of Scanning Electron Microscopy and quantitative analysis. The development of wild type <i>S. wisotonensis </i>was then compared to that of the mutant. In the second chapter of results, the cloning of 6 TCP genes in <i>S. wisotonensis is </i>reported <i>(SCHCYCI-6). To </i>identify the putative orthologs of <i>CYC, </i>a phylogenetic analysis was carried out using sequence information from other angiosperm TCP genes. This study showed that <i>SCHCYCl, 2 </i>and <i>3 </i>are the most likely candidates to control dorso-ventral asymmetry in <i>S. wisotonensis.</i> Finally, in the third chapter of results, the study of expression patterns obtained for <i>SCHCYCI-3 </i>using RNA <i>in situ </i>hybridisation in both the wild type and the mutant is reported. The results obtained from the morphological description and the study of gene expression patterns suggest that (i) the establishment of dorso-ventral asymmetry in <i>S. wisotonensis </i>follows a different dynamic to that in <i>A. majus (ii) SCHCYCI </i>may have a function related to that of <i>CYCLOIDEA </i>and <i>DICHOTOMA </i>but unlike for <i>A. majus, </i>it is likely to be restricted to the androecium (iii) <i>CYC</i>-like genes (i.e. <i>SCHCYC2-3) </i>may have a function in the development of the inflorescence where they are expressed in overlapping domains.