Objective
We want to understand the mechanism of stress-dependent, embryogenic induction in isolated, in-vitro cultured microspores and to use this knowledge for a genotype-independent production of doubled haploid plants in the crop plants barley, wheat, maize and carrot, as well as the model plant Arabidopsis thaliana. Doubled haploid breeding relates to the core of Mendelia plant breeding, i.e. the production of homozygous lines in sexually reproducing plants which transmit their traits to the offspring in a stable fashion. Doubled haploid breeding is an important tool to develop new cultivars directed to new demands in a much shorter time than by conventional breeding. A genotype- independent doubled haploid production would also be the core technology for a genotype-independent production of transgenic lines. There exist a number of techniques for the production of doubled haploids. In the last years the technique of isolated microspore cultures has emerged. This breakthrough has been achieved by the recognition that stress is the major trigger for embryogenic induction in microspores and that a combination of stress treatments allows a very large traction of microspores from a given plant to develop into plants. Furthermore, progress in transformation technology and the molecular analysis of pollen development and microspore embryogenesis has provided a number of useful developmental marker genes which can be used profitably for various purposes.
Microspore embryogenesis offers unique advantages to study plant embryogenesis, mainly due to the high number of microspores a plant produces in a naturally synchronous manner. This facilitates cell biological, biochemical, molecular and genetic analysis.
In the SIME (stress-induced microspore embryogenesis) project, we want to study first the signal transduction of the stresses which induce repeated cell divisions in the isolated microspores. Heat shock is a widely used inductive stress, and it is known that heat shock proteins are involved in embryogenic induction. We want to find out whether HSPs are causally related to embryogenic induction. Another effective stress is starvation. Since in lower eucaryotes starvation is an important developmental inducer (sporulation), we want to exploit the body of knowledge which has accumulated on sporulation and mating in these organisms. In particular we want to study the MAP kinase signaling pathway, including its upstream G-proteins.
The aim is to set up complete signal transduction cascades consisting of parallel tripartite MAP kinase module plus their respective G-proteins and to link these core cascades to upstream receptors and signals and to downstream recipients (transcription factors, cell cycle regulators) and effectors. A particular aspect will be the analysis of a possible activation of heat shock proteins by phosphorylation, i.e. the cross- talk between the two signaling pathways. In addition we want to focus on one of the hormones, i.e. auxin, whose synthesis is turned on as a consequence of embryogenic induction. Based on existing evidence that the MAP kinase pathway is involved in auxin signaling, we want to set up the complete auxin signaling cascade. A good critical mass of experts has been gathered in both, the heat shock and the MAP kinase activities. An important component of our analysis is the comparative use of transgenic dicot and monocot plants with anti-sense and dominant negative expression of signal transduction genes. A company is involved in these activities which will develop new imaging technology. Secondly, we want to identify new stresses, particularly chemical stresses which affect passage of cells through the cell cycle. The model compound is colchicin which is important for doubled haploid production in a dual sense. It has an inducing effect on microspore embryogenesis, and it is required for the doubling of the chromosomes. A replacement of colchicine might have beneficial social and ecological effects.
Thirdly, we take genetic and reverse genetic approaches to analyze SIME. Exploiting the advantages of the use of doubled haploids in genome mapping, a molecular marker-assisted back-cross strategy will be used to map genes involved in anther culture and microspore culture responsiveness on the maize genome map. Another approach is to set up microspore embryogenesis in Arabidopsis thaliana and to analyse existing embryo-lethal mutants for their phenotype and to persue chemical/physical complementation of the mutant embryos. A further approach which utilises A. thaliana is a reverse genetic one. Genes are isolated by differential display which are specifically expressed in particular stages of microspore embryogenesic the Arabidopsis EST library is screened for homologous sequences and tagged Arabidopsis mutant lines are PCR- tested to obtain lines which can be investigated for their phenotype.
Fourthly, we want to demonstrate, in a selected number of crop species (barley, wheat, maize) that the know-how developed in model species can be used to develop genotype-independent doubled haploid production. The know-how will also be applied to one important crop species which until now has been totally recalcitrant for microspore-derived doubled haploid production (carrot). A number of leading European breeding companies are included in this and the second activity.
The SIME project makes a deliberate attempt to bridge and bring together first class European basic science including the major players in the field of SIME and first class European plant breeding. The approach also allows to exploit spin-offs from the basic science work by the involved companies.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- natural sciencesbiological sciencesbiochemistrybiomoleculesproteins
- natural sciencesbiological sciencesdevelopmental biology
- natural sciencesphysical sciencesmolecular and chemical physics
- natural sciencesbiological sciencesgeneticschromosomes
- natural sciencesbiological sciencesgeneticsgenomes
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Call for proposal
Data not availableFunding Scheme
CSC - Cost-sharing contractsCoordinator
1030 WIEN
Austria