Instruments of functional genomics for the improvement of flower characteristics in ornamentals

Abstract

This present work aims to explore the technique of reverse genetics for the improvement of ornamental plants. For this purpose we have developed an Antirrhinum majus transformation protocol. The development of a genotyping assay for Agrobacterium tumefaciens and Escherichia coli lab strains based on DNA melting profiles of a 23S rDNA fragment has been of great help in the process of elaborating the transformation assay, since cross contamination of Agrobacterium tumefaciens stocks with Escherichia coli are difficult to identify by microbiological techniques, leading to false negative results in transformation experiments. For the improvement of ornamental plants, we concentrated on the study of genes that affect mostly the floral development in two species which are traditionally used as a model plants, but at the same time are of high economic interest, Antirrhinum majus, and Petunia x hybrida. We investigated the levels of DEFICIENS and GLOBOSA at late stages of petal development in the Antirrhinum majus mutants compacta, deficiens nicotianoides and globosa-1. We show that the threshold levels of DEF or GLO to obtain petal tissue are roughly 11% of wild-type. Our results demonstrate that at late stages of petal development, the B function transcriptional network topology is not based on positive autoregulation and has additional components of transcriptional maintenance. We also tested the use of AINTEGUMENTA as a tool to modify floral size in our two model plants, Petunia x hybrida and Antirrhinum majus. Downregulation of PhANT showed an effect on cell size while overexpression of AtANT in Petunia and Antirrhinum caused significant increases in cell expansion that could explain the differences in floral organ size. The differential effect of AtANT on limb and tube in Petunia and Antirrhinum correspond to phenotypic differences observed in natural variation in the corresponding genus indicating a relation between the phenotypic space of a genus and the effect of modified ANT levels, validating ANT as a gene to modify floral size. major genomes of animals, microorganisms and plants (Harris et al., 2004). The Gene Ontology Consortium (Consortium, 2001) has created three extensive ontologies to describe molecular functions, biological processes, and cellular components, and providing a community database resource that supports the use of these ontologies:-Biological process ontology: describes the sets of molecular events with a defined beginning and end, pertinent to the function of integrated living units such as cells, tissues, organs and organism. The biological process ontology may be inferred based on phylogenetic tools due to 2.5. CRISPR/CAS (Clustered Regularly Interspaced Short Palindromic Repeats) This technique is based on the defence mechanism in prokaryotes (Horvath and Barrangou, 2010), similar to RNAi in eukaryotes (Marraffini and Sontheimer, 2010). CRISPRs are short palindromic repeats in the prokaryotic genome, followed by short fragments of spacer DNA, which are integrated after a virus infection...