Phylogenetic analysis of the amino acid sequences of peridinin-containing protein complexes LHC from dinoflagellate transcriptomes, with emphasis on Prorocentrum cordatum (Ostenfeld) Dodge, 1975

Abstract

This research continues a series of studies of physiology and phylogeny of the potentially toxic dinoflagellate Prorocentrum cordatum (Ostenfeld) Dodge, 1975, a eukaryotic unicellular alga capable of forming harmful algal blooms (HABs) in marine coastal areas. P. cordatum is a highly adaptable invasive species, which recently colonized brackish-water Baltic Sea. HAB dynamics of this and other dinoflagellates are influenced by various abiotic and biotic factors, such as nutrient enrichment, temperature, salinity and irradiance. Light plays an important role in regulating the growth rate and nutrient assimilation by phytoplankton. Some dinoflagellate species possess unique pigments, such as peridinin, which is associated with light-harvesting protein complex acpPC, belonging to the LHC protein family. This protein binds chlorophyll a/c and carotenoids and functions as a light-harvesting antenna. In this work, we phylogenetically characterized the LHC-like amino acid sequences of dinoflagellates found in unannotated transcriptomes of the Marine Microbial Eukaryote Transcriptome Sequencing Project database (MMETSP). The obtained LHC-like sequences have strong phylogenetic relationships with homologous proteins of algae from other taxa and share typical conservative amino acid motifs with them. Phylogenetic analysis showed that the LHC-like sequenced dinoflagellates grouped together with other fucoxanthin-chlorophyll a/c-containing algae. Within this group, acpPC sequences from the peridinin-containing dinoflagellate species formed a well-supported distinct clade. The evolutionary relationships of peridinincontaining dinoflagellates P. cordatum with other dinoflagellates and various algal taxa were analyzed. The obtained results provide a deeper insight into advanced physiological adaptation strategies of bloom-forming dinoflagellates thus contributing to HABs modeling, forecasting and management.