INGENE · Integrating Nutrient economy in phytoplankton GENomics and Evolution

Phytoplankton support half of global primary production, fuel aquatic food webs, and drive global biogeochemical cycles. Phytoplankton transform inorganic nutrients into organic macromolecules. There is often a mismatch between the environmental availability of nitrogen (N) and phosphorus (P) and organismal requirements, which makes N and P important environmental stressors. These selective pressures affect genetic architecture and genome evolution in two ways, first as nucleic acids code for the genes responsible for nutrient uptake and second as they determine the N and P somatic requirements by defining the amino acids and nucleotides used to build proteins and RNA. The objective of INGENE is to estimate the impact of nutrients on the genomic structure and evolution of phytoplankton by following an interdisciplinary approach that combines laboratory experiments, genomics, bioinformatic analyses, and mathematical tools using ecologically important eukaryotic picoalgae as model phytoplankton organisms. Specifically, I will address the following sub-objectives: i) characterize the physiological traits and acclimation responses that define the uptake and use of P, ii) evaluate the impact of N and P availability on genetic architecture and genome evolution, iii) determine the effect of P availability on the whole genome mutation rate and spectrum, and iv) assess the links between genetic architecture and phenotypic physiological traits. Since eukaryotic picoalgae are the smallest known eukaryotic organisms, INGENE is poised to provide novel insights into our understanding of the minimal eukaryotic cellular structure. Moreover, by disentangling the effects of nutrient availability on phytoplankton at the molecular level, INGENE will improve our mechanistic understanding of the effect of nutrients on phytoplankton communities. This is particularly important to parametrize global models of the current global change scenario that is altering nutrient levels in the oceans.