Changes in gene expression of Prymnesium parvum induced by nitrogen and phosphorus limitation

Abstract

Prymnesium parvum is a globally distributed prymnesiophyte alga commonly found in brackish water marine ecosystems and lakes. It possesses a suite of toxins with ichthyotoxic, cytotoxic and hemolytic effects which, along with its mixotrophic nutritional capabilities, allows it to form massive Ecosystem Disruptive Algal Blooms (EDABs). While blooms of high abundance coincide with high levels of nitrogen (N) and phosphorus (P), reports of field and laboratory studies have noted that P. parvum toxicity appears to be augmented at high N:P ratios or P-limiting conditions. Here we present the results of a comparative analysis of P. parvum RNA-Seq transcriptomes under nutrient replete conditions, and N or P deficiency to understand how this organism responds at the transcriptional level to varying nutrient conditions. In nutrient limited conditions we found diverse transcriptional responses for genes involved in nutrient uptake, protein synthesis and degradation, photosynthesis, and toxin production. As anticipated, when either N or P was limiting, transcription levels of genes encoding transporters for the respective nutrient were higher than those under replete condition. Ribosomal and lysosomal protein genes were expressed at higher levels under either nutrient-limited condition compared to the replete condition. Photosynthesis genes and polyketide synthase genes were more highly expressed under P-limitation but not under N-limitation. These results highlight the ability of P. parvum to mount a coordinated and varied cellular and physiological response to nutrient limitation. Results also provide potential marker genes for further evaluating the physiological response and toxin production of P. parvum populations during bloom formation or to changing environmental conditions.

Metatranscriptome analysis reveals environmental and diel regulation of a Heterosigma akashiwo (raphidophyceae) bloom

“…Therefore, we set |log2 fold‐change| > 1 and adjusted P < 0.05 as the threshold for significant differential expression in the above‐described DEGs. Furthermore, many analyses have been based on the expression trend of multiple unigenes in the same metabolic pathway (Liu et al ., ). As evidence of consistency between qRT‐PCR and other two expression quantitation methods, several genes of H. akashiwo such as spt‐1 and ap , were consistently found to be significantly up‐regulated under the P‐limited condition in laboratory cultures as measured using qRT‐PCR (Supporting Information Fig.…”

“…A similar response was observed for NR in H. akashiwo grown under nitrate starvation (Coyne, ). When nitrate was provided as the sole N source, the transporters of nitrate, ammonium and urea were up‐regulated under N stress in many species, such as the prymensiophyte Prymnesium parvum and the pelagophyte A. anophagefferens (Wurch et al ., ; Liu et al ., ). In the current study, different N sources, including nitrate, ammonium and urea, were at measurable levels in the ambient environment.…”

Current Knowledge and Recent Advances in Marine Dinoflagellate Transcriptomic Research

“…Among the upregulated transcripts in S. trochoidea, glutamine synthetase and glutamate synthase were present, indicating increased investment in cellular ammonium assimilation potential [40]. The toxic alga Prymnesium parvum also had an overall higher expression of glutamine synthetase and glutamate synthase under nitrogen limited conditions, while the K. brevis transcriptome showed upregulation in glutamine synthase, nitrate/nitrite transporters and ammonium transporter genes [38,51]. Thus, these findings indicate that dinoflagellates may remodel their intracellular metabolism to utilize organic nitrogen such as urea under nitrogen limited conditions.…”

Weekly dynamics of abundance and size structure of specific nanophytoplankton lineages in coastal waters (Baltic Sea)

“…B–D). This may be explained by temporal niche separation, possibly resulting from differences in their physiology which has been well documented for cultured Prymnesium and Chrysochromulina species (e.g., Jones et al ; Hansen and Hjorth ; Graneli et al ; Liu et al ). The hypothesis of temporal niche separation was also supported by different correlations of studied algal groups with environmental variables (Fig.…”