AI Article Synopsis

  • Harmful algal blooms caused by cyanobacteria pose risks to ecosystems, the economy, and human health, with a focus on how nutrient introduction affects gene expression.
  • Through mesocosm experiments, researchers discovered that adding nitrogen (specifically urea) resulted in longer-lasting blooms by enhancing key biological processes like photosynthesis and toxin production.
  • The study highlights potential biomarkers for bloom longevity and sheds light on the mechanisms that allow cyanobacteria to thrive, which could aid in developing strategies to manage and mitigate these harmful blooms.

Article Abstract

Harmful algal blooms caused by cyanobacteria threaten aquatic ecosystems, the economy, and human health. Previous work has tried to identify the mechanisms that allow blooms to form, focusing on the role of nutrients. However, little is known about how introduced nutrients influence gene expression . To address this knowledge gap, we used mesocosms initiated with water experiencing a bloom. We added pulses of nutrients that are commonly associated with anthropogenic sources to the mesocosms for 72 hours and collected samples for metatranscriptomics to examine how the physiological function of and bloom status changed. The addition of nitrogen (N) as urea, but not the addition of PO, resulted in conspicuous bloom persistence for at least 9 days after the final introduction of nutrients. The addition of urea initially resulted in the upregulation of photosynthesis machinery, as well as phosphate, carbon, and N transport and metabolism. Once presumably became N-replete, upregulation of amino acid metabolism, microcystin biosynthesis, and other processes associated with biomass generation occurred. These capacities coincided with the upregulation of toxin-antitoxin systems, CRISPR- genes, and transposases suggesting that phage defense and genome rearrangement are critical in bloom persistence. Overall, our results show the stepwise transcriptional response of a bloom to the introduction of nutrients, specifically urea, as it is sustained in a natural setting. The transcriptomic shifts observed herein may serve as markers of the longevity of blooms while providing insight into why blooms over other cyanobacteria.IMPORTANCEHarmful algal blooms represent a threat to human health and ecosystems. Understanding why blooms persist may help us develop warning indicators of bloom persistence and create novel mitigation strategies. Using mesocosm experiments initiated with water with an active bloom, we measured the stepwise transcription changes of the toxin-producing cyanobacterium in response to the addition of nutrients that are important in causing blooms. We found that nitrogen (N), but not phosphorus, promoted bloom longevity. The initial introduction of N resulted in the upregulation of genes involved in photosynthesis and N import. At later times in the bloom, upregulation of genes involved in biomass generation, phage protection, genomic rearrangement, and toxin production was observed. Our results suggest that first fulfills nutritional requirements before investing energy in pathways associated with growth and protection against competitors, which allowed bloom persistence more than a week after the final addition of nutrients.

Download full-text PDF

Source
http://dx.doi.org/10.1128/spectrum.01369-24DOI Listing

Publication Analysis

Top Keywords

bloom persistence
20
bloom
11
gene expression
8
algal blooms
8
human health
8
initiated water
8
introduction nutrients
8
biomass generation
8
addition nutrients
8
upregulation genes
8

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!