ID: 613 / 9

Category: Symposia

Track: Pending

Proposed Symposium Title: THE EVOLUTION AND BIOGEOGRAPHY OF APOMICTIC PLANTS. SESSION 1

Abstract: Apomixis (ie., reproduction via asexually formed seeds) is taxonomically widespread in angiosperms. The reproductive pathways of apomixis are well characterized in many genera. The evolution, biogeography and diversity of apomictic plants, however, is still not well understood. Apomixis is strongly connected to hybridization and/or polyploidy, which makes it challenging to reconstruct the reticulate evolutionary history and phylogeny of such species complexes. The implementation of phylogenomic and population genomic methods in the last decade, together with novel bioinformatic pipelines, has enabled considerable progress in disentangling relationships of apomictic taxa. Crossing experiments have given insights into evolutionary origin and inheritance of apomixis. Diversification in space and time remains difficult to reconstruct because the fossil record does not reveal the mode of reproduction, and hence molecular dating and biogeographical analysis is difficult. Another challenge for estimating diversification is posed by classification of multiple asexual lineages and how to apply species concepts. The uncertainty of age estimates clouds evolutionary predictions of mutation accumulation (Muller’s ratchet) over time. Genomics and transcriptomics provide powerful methods to estimate genomic decay and the influence of facultative sexuality. Many apomictic complexes have occupied large distribution areas during and after the Pleistocene, usually exceeding those of their sexual relatives, a phenomenon known as Geographical Parthenogenesis. The various factors influencing these distribution patterns have been subject of biogeographical and ecological investigations in many genera. Large scale assessment of reproductive mode, e.g., via flow cytometric seed screenings, has provided detailed insights into spatial patterns of asexuality versus sexuality and has helped to identify tthe various abiotic and biotic factors shaping geographical distributions. In this symposium we will welcome presentations on cutting-edge research on these topics, including also multidisciplinary approaches.

Speaker 1: Kevin Karbstein Max Planck Institute for Biogeochemistry, Jena, Germany. email: kevin.karbstein@uni-goettingen.de Talk Title: Untying Gordian knots using phylogenomics: reticulate evolution in the apomictic Ranunculus auricomus complex

Speaker 2: Timothy Sharbel University of Saskatchewan, Saskatoon, Canada email: tim.sharbel@usask.ca Talk Title: The evolution and spread of apomixis in Boechera via haploid pollen: important tools for the application of apomixis to Brassica crops

Speaker 3: Ana Delaunay Caperta Instituto Superior de Agronomia, Lisboa, Portugal anadelaunay@isa.ulisboa.pt Talk title: Female-male crosstalk affects male meiosis and pollen development in sexual and apomictic Limonium species

Topics (Up to three): Hybrids and Hybridization

Topic 2: Biogeography / Phylogeography

Topic 3: Reproductive Biology

Justification: Our proposal bridges many research disciplines of this congress: Phylogenomics, Hybrids and Hybridization, Polyploidy, Biogeography/Phylogeography, Comparative Genomics / Transcriptomics, Evolutionary Biology, Systematics, and Reproductive Biology. Many research groups use multidisciplinary approaches to address the questions outlined in the abstract. We welcome contributions from angiosperms as well as from ferns, and hence we will represent a major proportion of the diversity of vascular plant life. Research on apomixis is scattered over the whole world, and we expect to have an international audience and collection of presentations. We are aiming at a balance of researchers at different career stages.