Photosynthetic euglenids are  a  group  of  pro*sts  with  plas*ds  in  the  supergroup  Excavata.  Their  plas*ds  originated  through  a  secondary  endosymbiosis.  A  heterotrophic  euglenid  engulfed  a  prasinophyte-­‐like  green  alga  and  maintained  it  as  a  permanent  endosymbiont.  The  majority  of  autotrophic  euglenids  live  in  freshwater  and  only  a  few  species  live  in  marine  or  brackish  habitats.  Freshwater  euglenids  are  abundant,  common  and  cosmopolitan  in  aqua*c  environments  and  they  were  first  *me  observed  under  microscope  already  in  1660’s  by  Antonie  van  Leeuwenhoek.      

Anna Karnkowska karnkowa@natur.cuni.cz Department of Parasitology, Charles University in Prague

Department of Molecular Phylogenetics & Evolution, University of Warsaw

We investigated ITS, COI and 18S rDNA as possible barcodes. Fragments V2-V3 and V4 of 18S rDNA could be successfully used for autotrophic euglenid species identification (with efficiency  above 90%).

Sampling in various environments might help to diminish the gap between described and sequenced species and identify new species.

Taxonomy & phylogeny In 1830, Ehrenberg described first photosynthetic euglenid - Euglena viridis. More than 3,000 taxa grouped in fourteen genera have been described since. Cells and their plastids exhibit a high degree of morphological diversity as in size, shape and plasticity. The main reason for describing so many taxa is an aforementioned large variation in morphological plasticity, despite the limited number of possible diagnostic features found in these unicellular organisms. This has led to a history of taxonomic duplications and re-descriptions, as well as the formulation of artificial classification schemes. Molecular phylogenies and detailed morphological studies have helped to resolve some of those taxonomic confusions as well as establish phylogenetic relationships among photosynthetic euglenids. Five molecular markers and a sampling of 59 taxa provided the most comprehensive tree of photosynthetic euglenids to date (Karnkowska et al. 2015). The resultant topology has strong nodal support for most of the branches and is consistent with all previous phylogenies. The monophyletic status of two families and 11 genera is well supported. However, genus Euglena remains polyphyletic and genus Phacus paraphyletic.

Origin of chloroplast The donor of chloroplast is, most likely a  prasinophyte-­‐like  green  alga, but specific green algal donor and early evolution of euglenid plastids are still uncertain. Rapaza viridis, a recently described mixotrophic euglenid, might shed a new light on euglenid endosymbiosis. Phylogenetic analyses and ultrastructural data demonstrated the intermediate features between phototrophic euglenids and phagotrophic lineages. The basal position within autotrophic euglenids suggested that R. viridis is the best candidate to illuminate original traits of euglenid plastids. Currently, we are analyzing transcriptome obtained from R. viridis to identify transcripts encoding putative plastid-targeted proteins. Phylogenetic analyses containing data from other euglenids and green algae will decipher evolutionary history of plastid-targeted proteins and euglenid plastid as such. In collaboration with Dr Naoji Yubuki, Charles university in Prague.

Establishing cultures of species not represented in culture collections is the best approach, but time consuming and often not successful. Whole genome amplification technique allows to obtain enough DNA for further phylogenetic analyses, without establishing culture.

As a result of comparative morphological and molecular research on groups of cryptic species many taxa were reclassified and their evolutionary relationships were resolved.

In collaboration with Prof. Richard E. Triemer, Michigan State University  

Approches  

In  collabora*on  with  Prof.  Bozena  Zakrys,  University  of  Warsaw.  

18S  rDNA  sequence  alone  is  as  favorable  as  five  molecular  markers  for  resolving  phylogene*c  

rela*onships.  

Only  5%  of    described  species  are  maintained  in  culture  collec*ons  and  are  represented  on  phylogene*c  trees.  

Some  strains  are  characterized  by  

unusually  long  SSU  rDNA  sequences.  The  longest  SSU  rDNA  sequence  to  date  comprising  6273  

bases.  

Rapaza  viridis