Hybridization and expression of apomixis

• Applicant: Professor Dr. Timothy Sharbel
• Co-Applicant: Professorin Dr. Elvira Hörandl
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2009 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 154994351

In flowering plants, hybridization and polyploidy are important evolutionary processes and are often connected to changes in the reproductive system. Nevertheless, it is still not well understood how these processes trigger the alterations of reproductive pathways. The main aim of the project is to study effects of interspecific hybridization and polyploidy on chromosomal composition, embryo sac development and embryogenesis, and components of asexual reproduction via seed (apomixis) in the Ranunculus auricomus complex, a natural apomictic polyploid complex. Alterations of reproductive phenotypes and gene expression will be studied in natural allopolyploid apomicts and their sexual parental species; experimentally produced homoploid and polyploid hybrids of related sexual species will be tested with respect to alterations in the developmental pathways and possible steps towards apomictic reproduction. We further want to test the hypothesis that hybridization alters the timing of gene expression regulating reproductive pathways, which may lead to apomictic phenotypes. We will first conduct a screening of the mode of reproduction via flow cytometric seed screening, cytological and embryological microscopic investigations, and molecular progeny tests (microsatellites) to sort out candidate individuals for expression profiling. On selected individuals, sequencing of the whole transcriptome will be conducted, and microarrays will be developed for a gene expression profiling in specific reproductive tissues. This approach will allow for a direct comparison for timing and location of gene expression in sexual species and their hybrid derivates in a system with natural apomixis. Results will be informative about changes in phenotype and gene expression in primary and more derived, apomictic hybrids. We expect to get insights into the constraints towards establishment of apomixis in flowering plants, which is of high relevance for both evolutionary questions and for a potential application of the apomixis technology in crops.

• DFG Programme: Research Grants
• International Connection: Austria