Molecular Insights into Nutrient-Driven Regulation of Trophic Strategies and Life-Cycle Shifts in Bloom-Forming Mixotrophic Dinoflagellates

Research into the molecular machinery of eukaryotic unicellular organisms (protists) offers a unique opportunity to unveil the mechanisms of intricate cellular processes and complete life cycles at the level of a single cell operating as a whole organism. Knowledge of protistan molecular biology and life-cycle shifts as adaptations to varying physical–chemical features of the environment helps resolve important issues like evaluation of the balance between external abiotic triggers and internal molecular drivers of cell development. Understanding the molecular mechanisms of these processes is crucial for prognostic modeling of the population growth of ecologically and economically important protists, like toxic species that form harmful algal blooms (HABs) that currently expand worldwide. Here, we review the basic features of bloom-forming mixotrophic dinoflagellates as drivers of their excess proliferation and HABs. We unveil key components of molecular machinery involved in life-cycle regulation of dinoflagellates and highlight the deficiency/redundancy of nitrogen- and phosphorus-containing substrates as modulators of life cycles, diversity and nutrition strategies, including mixotrophy and kleptoplasty. We discuss linkages between cellular and molecular biology, omics and ecological modeling, since merging the research approaches of these disciplines is a promising perspective for future progress of molecular biology within the framework of translational aquatic ecology.