Life in Silica: Deciphering the genetic blueprint for the ecological success of marine diatoms

Diatoms are the most ecologically successful eukaryotic phytoplankton, responsible for 20% of global photosynthetic carbon fixation, which is equivalent to the carbon uptake of the world’s rainforests.

Due to the complex evolutionary history of diatoms, much remains unknown about the specific functions and coordination of the thousands of genes underlying their global success.

We have recently sequenced the genome of the chain-forming diatom Skeletonema marinoi, a dominant genus of phytoplankton in the temperate oceans and coastal waters. Its 55 Mb genome contains over 22,000 genes, of which nearly 80% encode proteins of unknown function.

Here we propose an ambitious functional genomics project for S. marinoi to identify and characterize those genes that define the global success of marine diatoms.

Central to this goal is the establishment of the first large collection of randomly mutagenized but identifiably tagged transformants for a eukaryotic phytoplankton.

Together with several collaborative partners, we plan to screen the mutant collection under ecologically relevant conditions to determine the role of those genes that define key diatom features and how these adapt to changing environmental conditions due to increased human activities.

Our group will specifically focus upon those genes responsible for the highly elaborate cell walls unique to diatoms composed of biogenic silicates and how these influence the global cycling of carbon and other key nutrients and minerals.