Date: 15th January 2020
Title: Evolution and functional diversification of EXO70 subunits of exocyst complex in land plants
Location: Seminar room 5405, Biocentre 3, Viikinkaari 1
Host: Michael Wrzaczek
Abstract: Localized delivery of plasma membrane and cell wall components is an essential process in all plant cells. Vesicle tethering complex exocyst, an ancient eukaryotic hetero-octameric cellular module, is an important regulator of these processes. Analyses of land plant genomes lead to the surprising prediction of multiple putative EXO70 exocyst subunit paralogs. They form three distinct subfamilies – EXO70.1, EXO70.2 and EXO70.3 - present in the common ancestor of all land plants. EXO70.1 subfamily represented by a housekeeping EXO70A isoforms is the least evolutionarily dynamic one, closely related to single EXO70 subunits encoded in fungal and animal genomes. Discovery of exocyst complex involvement in the autophagy process, assisted by some members of the EXO70.2 extraordinarily evolving subfamily, was a great surprise. Members of this subfamily are implied in processes related to autophagy, secondary metabolites transport, but also cell growth regulation, secondary cell wall modification and especially defence. EXO70.3 subfamily seem to be involved in cellular coordination including symbiotic interactions.
Viktor Žárský established the Laboratory of cell biology at the Institute of experimental botany, Czech academy of sciences and is at the same time professor at the Department of experimental plant Biology, Charles University in Prague. His researches focus on the biology of plant cell polarity and morphogenesis regulated by small GTPases and their effectors in endomembrane system, especially vesicle tethering complex exocyst.