Comparative and Functional Genomics of Macronutrient Utilization in Marine Diatoms

Macronutrient availability and distribution across ocean provinces controls the distribution, abundance, and productivity of marine diatoms. Diatoms are a particularly successful group of phytoplankton thought to possess mechanisms that allow for rapid response and acclimation to shifting nutrient conditions while sustaining high rates of growth. Since the early 2000s, the availability of diatom genomes, functional genomics, and acceleration in development of genetic tools has led to the identification and characterization of adaptations diatoms possess that help explain their ecological dominance under certain conditions. The molecular basis of the ability of diatoms to outcompete other taxa for available nitrogen has been established and understanding the sensing, regulation, and other nuances of this response continues to be a major theme of ongoing research in the field. Further, major developments in the phosphorus uptake and sensing machinery of diatoms have emerged, enabled entirely by genome-enabled research. Additional knowledge of the acquisition machinery used for silicon uptake and metabolism of sulfur compounds has also resulted from analysis of diatom genomes. In this chapter, we review studies on macronutrient utilization in diatoms from the lab and in the field, highlight several notable insights that have emerged from this first era of diatom molecular research, and identify emerging paradigms that represent exciting areas for future study.