Developing new model organisms among marine holozoans, the closest unicellular relatives of animals

MARIA CRISTINA ARESTE; MARIA RUBIO; SEBASTIÁN R. NAJLE; IÑAKI RUIZ-TRILLO; ELENA CASACUBERTA

Heidelberg

Simposio; EMBO-EMBL Symposium: A new age of discovery for aquatic microeukaryotes; 2016

European Molecular Biology Organization (EMBO-EMBL)

The holozoa includes Metazoa, probably the eukaryotic clade with the most complex body plans, as well as several protists lineages, some of which seem to be quite abundant in the oceans. These holozoan unicellular lineages include the Choanoflagellata, the Filasterea, the Ichthyosporea, and the Corallochytrea, comprising and incredible diversity of morphologies and cell behaviors. However, our knowledge of their biology and ecology remains quite poor. More importantly, given their key phylogenetic position as closely related to animals and their potential ecological importance, development of experimentally tractable holozoans will allow deeper understanding of the evolution of animals, the origin of those cell morphologies and the ecological role of those marine taxa. However, and even though there has been important work done in some holozoans, such as choanolagellates and the filasterean Capsaspora owczarzaki, there is not yet a unicellular holozoan that can be considered a model organism. To fill this gap, we are currently screening for transformability five representative marine taxa from the less known holozoan lineages (i.e., filastereans, ichthyosporeans, and corallochytreans). We here present our work to elucidate their life cycles and our systematic screening for a transformation protocol for each of those taxa. Future directions are discussed.