Despite the harsh environmental conditions in polar oceans, these ecosystems harbour significant biodiversity. How this biodiversity underpinning productive ecosystems and resources for novel products used in biotechnology, agriculture and medicine has evolved largely remains unknown. One reason for this knowledge gap is that we only know little as to how mutation and recombination as major evolutionary forces shape polar organisms and therefore their genes enabling them to thrive under the harsh polar growth conditions. Arguably, most of the genetic variation driving biological diversity stems from mutations. As their rate is temperature dependent with increasing mutation rates at the extreme ends, it suggests that polar organisms likely need to cope with higher mutational loads. Polar diatom genomes have provided evidence that these microalgae benefit from elevated mutation rates, generating genetic diversity to respond to fast-changing environmental conditions (e.g. freezing and melting) in the absence of sexual recombination. However, direct experimental evidence is missing. Thus, this PhD studentship will investigate if DNA damage is enhanced in a polar diatom vs a non-polar counterpart and how mitotic recombination contributes to the genetic variation that is adaptive. The student will use fluorescence-based assays in combination with genome re-sequencing to quantify DNA damage after cold and heat stress in a polar and a nonpolar diatom species. To test how DNA-repair induced mitotic recombination contributes to genetic variation and differences between both diatom species, the student will knock out two core DNA-repair enzymes (BRCA2, KU70) and will reveal subsequent effects on DNA damage and fitness (Growth rates) under temperature stress. Thus, data from this project will lay the foundation for how the extreme polar environment shapes the evolution of genes and genomes in polar phytoplankton underpinning productive food webs and resources for novel enzymes used in biotechnology.
Petra Bulánková, Mirna Sekulić, Denis Jallet, Charlotte Nef, Tom Delmont, Cock van Oosterhout, Ilse Vercauteren, Cristina Maria Osuna-Cruz, Emmelien Vancaester, Thomas Mock, Koen Sabbe, Fayza Daboussi, Chris Bowler, Wim Vyverman, Klaas Vandepoele, Lieven De Veylder (2021) Mitotic interhomolog recombination drives genomic diversity in diatoms. Current Biolog (https://www.cell.com/current-biology/fulltext/S0960-9822(21)00672-2)
Drahomíra Faktorová, R. Ellen R. Nisbet, José A. Fernández Robledo, Elena Casacuberta, Lisa Sudek, Andrew E. Allen, Manuel Ares Jr., Cristina Aresté, Cecilia Balestreri, Adrian C. Barbrook, Patrick Beardslee, Sara Bender, David S. Booth, François-Yves Bouget, Chris Bowler, Susana A. Breglia, Anita Broellochs, Colin Brownlee, Gertraud Burger, Heriberto Cerutti, Rachele Cesaroni, Miguel A. Chiurillo, Thomas Clemente, Duncan B. Coles, Jackie L. Collier, Liz Cooney, Kathryn Coyne, Roberto Docampo, Christopher L. Dupont, Virginia Edgcomb, Elin Einarsson, Pía A. Elustondo, Fernan Federici, Veronica Freire-Beneitez, Nastasia J. Freyria, Kodai Fukuda, Paulo A. García, Peter R. Girguis, Fatma Gomaa, Sebastian Gornik, Jian Guo, Vladimír Hampl, Yutaka Hanawa, Esteban R. Haro-Contreras, Elisabeth Hehenberger, Andrea Highfield, Yoshihisa Hirakawa, Amanda Hopes, Christopher J.Howe, Ian Hu, Jorge Ibañez, Nicholas A.T. Irwin, Yuu Ishii, Natalia Ewa Janowicz, Adam C. Jones, Ambar Kachale, Konomi Fujimura-Kamada, Binnypreet Kaur, Jonathan Z. Kaye, Eleanna Kazana, Patrick J. Keeling, Nicole King, Lawrence A. Klobutcher, Noelia Lander, Imen Lassadi, Zhuhong Li, Senjie Lin, Jean-Claude Lozano, Fulei Luan, Shinichiro Maruyama, Tamara Matute, Cristina Miceli, Jun Minagawa, Mark Moosburner, Sebastián R. Najle, Deepak Nanjappa, Isabel C. Nimmo, Luke Noble, Anna M.G. Novák Vanclová, Mariusz Nowacki, Isaac Nuñez, Arnab Pain, Angela Piersanti, Sandra Pucciarelli, Jan Pyrih, Joshua S. Rest, Mariana Rius, Deborah Robertson, Aldane Ruaud, Iñaki Ruiz-Trillo, Monika A. Sigg, Pamela A. Silver, Claudio H. Slamovits, Estienne Swart, G. Jason Smith, Brittany Sprecher, Rowena Stern, Tobias von der Haar, Lev Tsypin, Aaron Turkewitz, Jernej Turnšek, Matus Valach, Valérie Vergé, Peter von Dassow, Anastasios Tsaousis, Ross F. Waller, Lu Wang, Xiaoxue Wen, Glen Wheeler, April Woods, Huan Zhang, Thomas Mock, Alexandra Z. Worden, Julius Lukeš. (2020) Genetic tool development in marine protists: Emerging model organisms for experimental cell biology. Nature Methods (https://doi.org/10.1038/s41592-020-0796-x)
Mock T., Otillar R.P., Strauss J., McMullan M., Paajanen P., Schmutz J., Salamov A., Sanges R., Toseland A., Ward B.J., Allen A.E., Dupont C.L., Frickenhaus S., Maumus F., Veluchamy A., Wu T., Barry K.W., Falciatore A.,Ferrante M.I., Fortunato A.E., Glöckner G., Gruber A., Hipkin R., Janech M.G., Kroth P.G., Leese F., Lindquist E.A., Lyon B.R., Martin J., Mayer C., Parker M., Quesneville H., Raymond J.A., Uhlig C., Valas R.E., Valentin K.U. Worden A.Z., Armbrust E.V., Clark M.D., Bowler C., Green B.R. Moulton V., Van Oosterhout C., Grigoriev I.V. (2017) Evolutionary genomics of the cold-adapted diatom Fragilariopsis cylindrus. Nature (DOI: 10.1038/nature20803)