Appling High Throughput Sequencing (HTS) on Snow Algae: current state, knowledge gaps and future perspectives

Remias, D. (Speaker)

Activity: Talk or presentationOral presentation

Description

Cryoflora consists of specialized microalgae which are mainly Chlorophyta, with an emphasis on Chlamydomonadaceae. Blooms cause snow discolorations in mountainous or polar habitats during spring and summer. Exploration of the biodiversity of cryoflora has been hampered by weak morphologic details of spore stages dominating the snow surface and the fact that many taxa were not yet culturable for life cycle studies. In the last few years, HTS has been successfully performed on environmental samples, including characterisation of biocoenosis data of bacteria and fungi living in snow. It allows an in-depth characterization of communities and reveals also low abundance taxa. However, this complement to classic sequencing raised several questions, especially taking the poor resolution of the 18S rDNA marker gene in the Chlamydomonadaceae into account. In addition, the short read length of HTS can only target a fraction of the marker genes, which must be chosen with care. In our approach, we analysed four snow algae from the Austrian Alps (Chlamydomonas nivalis, Chloromonas brevispina, Chlainomonas sp. and Chloromonas rosae var. psychrophila) by HTS and Sanger sequencing, using 18S and ITS2 genes. We found that evaluation of the data was highly affected by the quality of the databases, which depend on the submission of references sequences derived from classic sequencing of single taxa. Furthermore, the multitude of sequences derived from HTS can reveal the existence of oligotypes within one taxon. In sum, we attempted to show the current state and limits for designating OTUs and thus estimating the true biodiversity of Alpine cryoflora.
Period17 Aug 2017
Event title11th International Phycological Congress: null
Event typeWorkshop
LocationStettin, Poland