Unicellular opisthokonts diversity and distribution in the European coast

Abstract

Unicellular opisthokonts include relevant eukaryotic lineages both from an evolutionary and an ecological point of view. They include interesting organisms such as the bacterivorous choanoflagellates, the poorly known filastereans, the nucleariids or the parasites ichthyosporeans. We analyzed all the published environmental clone libraries in order to have an approximation to the relative abundance of unicellular opisthokonts (except fungi) in the environment. We focus on filastereans, ichthyosporeans and nucleariids, and we update the previous analysis done with choanoflagellates. Based on the information retrieved from these 18S rDNA clone libraries we constructed an opisthokont phylogenetic tree. It has been used as guide-tree to analyze the taxonomy of the 18SrDNA and rRNA data obtained by high-throughput methods from the European coast in the context of the BioMarks project. Using this data we have described the abundance and the distributions of the studied groups in different sampling points and size fractions. Furthermore, the comparison between 18SrDNA and rRNA helped us to determine the most abundant and active groups. The analysis of environmental clone libraries and the use of highthroughput techniques are useful approaches to increase the knowledge on the diversity of unicellular opisthokonts and to have a better sketch of its putative ecological role