Epigenetic mechanisms leading to genetic flexibility during abiotic stress responses in microalgae: A review

Epigenetics plays important roles in adaptation processes in microalgae. Due to fluctuating ambient conditions, cells must continually convert fundamental biological pathways, which entail alterations in gene expression. At the molecular level, epigenetics includes heritable or reversible chemical modifications targeting DNA and surrounding histone proteins that can alter tertiary and quaternary DNA structures and thus affect transcription factor access and gene expression. Chlorophyceae exhibit very specific types of epigenetic regulation. To date, little is known about the epigenetic mechanisms involved in stress adaption and metabolite production. Thus, a deeper understanding of microalgal biochemical pathways is required. To enable further elucidation of these pathways, the present study summarizes the currently available information about epigenetic changes that occur in microalgae during environmental stress exposure. The review focuses primarily on the effects of light, heat shock and nutrient element intake to prompt further research on the regulatory mechanisms and metabolic pathways of microalgae.