Sensing and Signalling in Diatom Responses to Abiotic Cues.

Diatoms are prominent microalgae that proliferate in a wide range of aquatic
environments. Still, fundamental questions regarding their biology, such as how
diatoms sense and respond to environmental variations, remain largely unanswered.
In recent years, advances in the molecular and cell biology of diatoms
and the increasing availability of genomic data have made it possible to explore
sensing and signalling pathways in these algae. Pivotal studies of photosensory
perception have highlighted the great capacity of diatoms to accurately detect
environmental variations by sensing differential light signals and adjust their
physiology accordingly. The characterization of photoreceptors and light dependent
processes described in this review, such as plastid signalling and diel
regulation, is unveiling sensing systems which are unique to these algae,
reflecting their complex evolutionary history and adaptation to aquatic life.
Here, we also describe putative sensing components involved in the responses
to nutrient, osmotic changes, and fluid motions. Continued elucidation of the
molecular systems processing endogenous and environmental cues and their
interactions with other biotic and abiotic stress signalling pathways is expected
to greatly increase our understanding of the mechanisms controlling the abundance and distribution of the highly diverse diatom communities in marine
ecosystems.