Sex in marine planktonic diatoms: insights and challenges
Montresor, Marina; Vitale, Laura; D’Alelio, Domenico; Ferrante, Maria Immacolata
Abstract Diatoms are diploid eukaryotic microalgae, key-players in the ocean and are responsible for a large fraction of the global primary production. These unicellular microalgae have a unique life cycle characterized by progressive cell size reduction; the restitution of the large cell size is accomplished within the sexual phase. Here we summarize the available evidence for the presence of sex in marine planktonic diatoms and results of more recent investigations aimed at defining environmental or endogenous cues for sexualisation. Genomic resources are now opening up new avenues for elucidating the molecular mechanisms involved in different aspects of the sexual phase, such as cell size control, mating type definition, meiosis, and gamete recognition systems. Understanding the regulatory mechanisms and signalling pathways underlying the onset of sex in diatoms will provide important information to comprehend their ecological and evolutionary success.