Temperature and light interactively modulate gene expression in Saccharina latissima (Phaeophyceae)

Area of Science:

• Marine Biology
• Ecology
• Molecular Biology

Background:

• Kelp (Laminariales) are crucial to cold-temperate coastal ecosystems.
• Light (UV) and temperature significantly influence kelp distribution and productivity.
• Global environmental changes pose a threat to kelp populations.

Purpose of the Study:

• To investigate the combined effects of UV radiation and temperature on kelp gene expression.
• To understand the molecular mechanisms of acclimation to these combined stresses in Saccharina latissima.
• To identify specific genes and pathways involved in stress response.

Main Methods:

• Sporophytes of Saccharina latissima were exposed to 12 combinations of photosynthetically active radiation (PAR), UV radiation, and temperature for two weeks.
• Microarray hybridizations were used to analyze changes in gene expression patterns.
• Gene expression profiles were correlated with physiological responses.

Main Results:

• UV radiation had a stronger effect on gene expression than high PAR.
• Temperature significantly affected gene expression, with the strongest impact observed at 2°C.
• Higher temperatures mitigated the negative effects of UV radiation.
• Gene expression indicated compartment-specific regulation of reactive oxygen species (ROS) scavenging.
• Transcriptomic responses were observed even at stress levels that did not cause physiological alterations.

Conclusions:

• Saccharina latissima exhibits complex transcriptomic responses to combined UV radiation and temperature stress.
• Molecular acclimation mechanisms involve specific gene categories like photosynthesis and vitamin B6 biosynthesis.
• Understanding these molecular responses is vital for predicting kelp's fate under climate change.