Dimorphism in the Antarctic cryptophyte Geminigera cryophila (Cryptophyceae)

Area of Science:

• Microbiology
• Algology
• Molecular Biology

Background:

• Cryptophytes are diverse algae, but their taxonomy can be challenging.
• Antarctic aquatic environments harbor unique microbial life adapted to extreme conditions.

Purpose of the Study:

• To identify and classify pink to red-pigmented cryptophytes isolated from Antarctic saline lakes.
• To investigate the taxonomic relationship of these isolates using morphological, chemical, and molecular data.

Main Methods:

• Isolation and cloning of cryptophyte strains from Bayly Bay and Ace Lake.
• Morphological and ultrastructural analysis using light and electron microscopy.
• Pigment extraction and spectrophotometry (Cr-phycoerythrin 545 identification).
• Partial 18S SSU ribosomal gene sequencing and molecular phylogenetic analysis.

Main Results:

• Morphological and pigment analysis suggested potential taxonomic affinities but were inconclusive.
• Molecular phylogenies consistently placed both isolates close to Geminigera cryophila.
• Evidence indicated the isolates represent a cryptomorph (dimorphic form) of G. cryophila.

Conclusions:

• The Antarctic cryptophyte isolates are identified as a cryptomorph of Geminigera cryophila.
• Molecular data are crucial for resolving taxonomic ambiguities in morphologically similar cryptophytes.
• The study supports the concept of cryptophyte dimorphism, where distinct cell-types can be mistaken for new species.