Growth on ATP Elicits a P-Stress Response in the Picoeukaryote Micromonas pusilla.

The surface waters of oligotrophic oceans have chronically low phosphate (Pi) concentrations, which renders dissolved organic phosphorus (DOP) an important nutrient source. In the subtropical North Atlantic, cyanobacteria are often numerically dominant, but picoeukaryotes can dominate autotrophic biomass and productivity making them important contributors to the ocean carbon cycle. Despite their importance, little is known regarding the metabolic response of picoeukaryotes to changes in phosphorus (P) source and availability.

Genetic indicators of iron limitation in wild populations of Thalassiosira oceanica from the northeast Pacific Ocean.

Assessing the iron (Fe) nutritional status of natural diatom populations has proven challenging as physiological and molecular responses can differ in diatoms of the same genus. We evaluated expression of genes encoding flavodoxin (FLDA1) and an Fe-starvation induced protein (ISIP3) as indicators of Fe limitation in the marine diatom Thalassiosira oceanica. The specificity of the response to Fe limitation was tested in cultures grown under Fe- and macronutrient-deficient conditions, as well as throughout the diurnal light cycle.

The transcriptome and proteome of the diatom Thalassiosira pseudonana reveal a diverse phosphorus stress response.

Phosphorus (P) is a critical driver of phytoplankton growth and ecosystem function in the ocean. Diatoms are an abundant class of marine phytoplankton that are responsible for significant amounts of primary production. With the control they exert on the oceanic carbon cycle, there have been a number of studies focused on how diatoms respond to limiting macro and micronutrients such as iron and nitrogen.

Characterization of putative iron responsive genes as species-specific indicators of iron stress in thalassiosiroid diatoms.

Iron (Fe) availability restricts diatom growth and primary production in large areas of the oceans. It is a challenge to assess the bulk Fe nutritional health of natural diatom populations, since species can differ in their physiological and molecular responses to Fe limitation. We assayed expression of selected genes in diatoms from the Thalassiosira genus to assess their potential utility as species-specific molecular markers to indicate Fe status in natural diatom assemblages.

Empirical bayes analysis of sequencing-based transcriptional profiling without replicates.

Background: Recent technological advancements have made high throughput sequencing an increasingly popular approach for transcriptome analysis. Advantages of sequencing-based transcriptional profiling over microarrays have been reported, including lower technical variability. However, advances in technology do not remove biological variation between replicates and this variation is often neglected in many analyses.