Molecular fingerprints of cell size sensing and mating type differentiation in pennate diatoms.

A unique cell size-sensing mechanism is at the heart of the life cycle of diatoms. During population growth, cell size decreases until a sexual size threshold (SST) is reached, below which cells become sexually competent. In most pennate diatoms, the two mating types undergo biochemical and behavioral differentiation below the SST, although the molecular pathways underlying their size-dependent maturation remain unknown.

Transcriptional chronology reveals conserved genes involved in pennate diatom sexual reproduction.

Sexual reproduction is a major driver of adaptation and speciation in eukaryotes. In diatoms, siliceous microalgae with a unique cell size reduction-restitution life cycle and among the world's most prolific primary producers, sex also acts as the main mechanism for cell size restoration through the formation of an expanding auxospore. However, the molecular regulators of the different stages of sexual reproduction and size restoration are poorly explored.

Pheromone Mediated Sexual Reproduction of Pennate Diatom Cylindrotheca closterium.

Benthic diatoms dominate primary production in marine subtidal and intertidal environments. Their extraordinary species diversity and ecological success is thought to be linked with their predominantly heterothallic sexual reproduction. Little is known about pheromone involvement during mating of pennate diatoms.

Author Correction: The Seminavis robusta genome provides insights into the evolutionary adaptations of benthic diatoms.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The Seminavis robusta genome provides insights into the evolutionary adaptations of benthic diatoms.

Benthic diatoms are the main primary producers in shallow freshwater and coastal environments, fulfilling important ecological functions such as nutrient cycling and sediment stabilization. However, little is known about their evolutionary adaptations to these highly structured but heterogeneous environments. Here, we report a reference genome for the marine biofilm-forming diatom Seminavis robusta, showing that gene family expansions are responsible for a quarter of all 36,254 protein-coding genes.

Incomplete Reproductive Isolation Between Genetically Distinct Sympatric Clades of the Pennate Model Diatom Seminavis robusta.

Incomplete reproductive isolation between genetically distinct taxa provides an interesting opportunity for speciation and adaptation studies. This phenomenon is well-described in macro-organisms, but less experimental evidence is available for unicellular eukaryotes. Here, we document the sympatric occurrence of genetically differentiated populations of the pennate model diatom Seminavis robusta in coastal subtidal biofilm communities and show widespread potential for gene flow between them.