A novel evolutionary strategy revealed in the phaeoviruses

Area of Science:

• Marine virology
• Algal biology
• Evolutionary biology

Background:

• Phaeoviruses infect brown algae, crucial primary producers in coastal ecosystems.
• They uniquely employ a persistent evolutionary strategy (K-selected) via genome integration, unlike typical acute lytic (r-selected) giant viruses.
• Brown algae are vital to marine primary production.

Purpose of the Study:

• To investigate the genetic diversity of phaeoviruses within filamentous brown algae.
• To understand the evolutionary strategies of phaeoviruses in relation to other giant algal viruses.

Main Methods:

• Genome screening of five filamentous brown algal species.
• Analysis of viral gene sequence variants.

Main Results:

• Discovery of unprecedented genetic diversity in phaeoviral genomes, particularly in smaller genomes.
• Identification of a phaeoviral variant exhibiting characteristics of both major phaeovirus subgroups.
• Phaeoviruses demonstrate a unique combination of reduced dsDNA genomes and loss of DNA proofreading (acute traits) while retaining a persistent strategy.

Conclusions:

• Phaeoviruses display remarkable genetic diversity and a unique evolutionary strategy, merging traits from different life strategies.
• This adaptability allows them to thrive in their ecological niche within brown algae.