Project Details
Projekt
Re-evaluating taxonomy and distribution patterns of the Xanthophyceae (Stramenopiles)
Applicant
Dr. Nataliya Rybalka
Subject Area
Evolution and Systematics of Plants and Fungi
Term
from 2017 to 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 351914121
Xanthophyceae is a group of algae, important primary producers in terrestrial as well as freshwater ecosystems and promising for biotechnological exploitation. Attempts to further explore their ecological significance and exploitation are, however, hampered by the absence of clear species delimitations, the presence of cryptic species complexes and extensive morphological plasticity. We assume xanthophytes are more diverse and abundant than recognized until now. Therefore, project is divided into two tasks closely interlinked with each other, (1) a clarification of the taxonomy of the group with newly defined genera and species and (2) further investigation of habitat preferences, speciation processes as well as recovering and naming of new species and lineages of xanthophytes. Using high-resolution molecular markers monophyletic entities (species and genera) will be recovered from previous cryptic species complexes. A broad range of culture strains available from culture collections, individual collaborating researchers and own new isolates established also during the project will be examined to build up a database of reference sequences. Using the monophyletic species concept species of Xanthophyceae will be delimitated when the three markers, ITS2 incl. secondary structure comparisons, psbA/rbcL-spacer region, and full rbcL sequences congruently recover a clear and robust phylogenetic structure. Names of the xanthophyte species will be anchored to epitypes, established from suitable reference cultures in cryopreserved state to fulfil ICN requirements. For speciation and ecological preferences of the Xanthophyceae it will be tested whether the re-defined xanthophyte species are adapted to rather narrow ecological niches and which abiotic parameters shape the diversity and taxonomic composition of Xanthophyceae communities. With a high-throughput meta-barcoding approach the diversity and distribution patterns across various habitats and geographical regions of Xanthophyceae will be studied on a broader scale. A large number of environmental samples, i.e. from freshwater, soil and other terrestrial habitats will be examined for their taxonomic composition of xanthophyte communities, employing group-targeted amplicon sequencing generated as paired-ends reads on Illumina MiSeq platforms. Because xanthophytes represent an abundant and important group of microorganisms in soil, we aim to correlate distribution patterns of Xanthophyceae species in soils with the physicochemical properties of their soil substrate in order to test for abiotic factors test that may determine xanthophyte community structures in soil. By using samples from rather distant geographical regions, preferences towards certain habitats can be tested independent of geographical distribution.
DFG Programme
Priority Programmes
