Common environmental stress responses in a model marine diatom

Marine planktonic diatoms are among the most important contributors to phytoplankton blooms and marine net primary production. Their ecological success has been attributed to their ability to rapidly respond to changing environmental conditions. Here, we report common molecular mechanisms used by the model marine diatom Thalassiosira pseudonana to respond to 10 diverse environmental stressors using RNA-Seq analysis. We identify a specific subset of 1076 genes that are differentially expressed in response to stressors that induce an imbalance between energy or resource supply and metabolic capacity, which we termed the diatom environmental stress response (d-ESR). The d-ESR is primarily composed of genes that maintain proteome homeostasis and primary metabolism. Photosynthesis is strongly regulated in response to environmental stressors but chloroplast-encoded genes were predominantly upregulated while the nuclear-encoded genes were mostly down-regulated in response to low light and high temperature. In aggregate, these results provide insight into the molecular mechanisms used by diatoms to respond to a range of environmental perturbations and the unique role of the chloroplast in managing environmental stress in diatoms. This study facilitates our understanding of the molecular mechanisms underpinning the ecological success of diatoms in the ocean.

Automated summary

Marine planktonic diatoms, including Thalassiosira pseudonana, play a vital role in phytoplankton blooms and marine primary production due to their ability to respond quickly to environmental changes. Through RNA-Seq analysis, this study identified a subset of 1076 genes termed the diatom environmental stress response (d-ESR) that are differentially expressed in response to various stressors affecting energy balance and metabolic capacity. It was found that the d-ESR mainly consists of genes involved in maintaining proteome homeostasis and primary metabolism. Additionally, the study revealed the regulation of photosynthesis and the unique role of chloroplast in managing environmental stress in diatoms.