Identification of phytoplankton isolates from the eastern Canadian waters using long-read sequencing

Area of Science:

• Marine biology
• Microbial ecology
• Genomics

Background:

• Phytoplankton are crucial primary producers influencing marine biogeochemical cycles.
• Accurate identification of phytoplankton strains is vital for ecological research and understanding environmental changes.
• Existing reference databases have limitations in taxonomic resolution for certain phytoplankton groups.

Purpose of the Study:

• To isolate and genetically characterize phytoplankton strains from eastern Canadian waters.
• To expand the reference database for phytoplankton identification using long-read sequencing.
• To improve the taxonomic resolution of phytoplankton in marine environments.

Main Methods:

• Isolation and culturing of 73 phytoplankton strains.
• Genetic characterization using long rRNA gene sequencing (~4000 bp) covering 18S, ITS, and 28S rRNA regions.
• Long-read sequencing technology for generating comprehensive rRNA gene sequences.

Main Results:

• 66% of strains were accurately identified using partial 18S rRNA gene sequences.
• The 28S rRNA reference database was expanded with 41 distinct strains, including 30 new species.
• New long-read reference sequences were generated for genera like Picochlorum and Droopiella, and a Chaetoceros similis strain was characterized.

Conclusions:

• This study significantly enhances the available long-read reference sequences for phytoplankton.
• The expanded database improves the accuracy of phytoplankton identification from environmental samples.
• The findings contribute to a better understanding of marine microbial diversity and phytoplankton taxonomy.