Recent Advances in Understanding the Sex Pheromone-Mediated Communication of Diatoms

Diatoms are prolific unicellular microalgae, contributing ≈20% of global photosynthetic CO₂ fixation. These algae form the base of the marine food web. They are also widely distributed in freshwater and utilized in aquaculture. Despite their ecological and economic significance, many fundamental aspects of diatom biology, including their sexual reproduction, remain poorly understood. This review highlights recent advances in unraveling the chemical signaling essential for diatom sexual reproduction and introduces how natural products chemistry and marine microbiology synergize to unravel novel chemical communication strategies. Diatoms communicate through a sophisticated pheromone-based "language" that synchronizes cell cycles, regulates the physiology, and guides cells to their mating partners. The structural elucidation of diatom pheromones becomes possible with emerging model organisms and the development of analytical approaches to detect these compounds at extremely low active concentrations. Breakthroughs in comparative metabolomics, combined with reliable bioassays, have enabled the identification of the first pheromones. However, only the adaptation of novel labeling techniques and sensitive NMR experiments allows the determination of the pheromone structures. With these structural insights and the availability of genetic resources, a new research field is emerging-spanning evolutionary studies to the potential manipulation of natural diatom populations and applications in aquaculture.