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AME prepress abstract   -  DOI: https://doi.org/10.3354/ame01939

Influence of increased nutrient supply on Microcystis aeruginosa at cellular and proteomic levels

Yunhan JIANG, Ying LIU*

*Corresponding author:

ABSTRACT: Various studies observed that increased nutrient supply promoted the growth of bloom-forming cyanobacteria, but only a limited number of studies investigated the influence of increased nutrient supply on bloom-forming cyanobacteria at the proteomic level. This study investigated the cellular and proteomic responses of Microcystis aeruginosa to elevated nitrogen and phosphorus supply. Increased supply of both nitrogen and phosphorus significantly promoted (p < 0.05) the growth of M. aeruginosa and the synthesis of chlorophyll a, protein, and microcystins. The release of microcystins and the synthesis of polysaccharides negatively correlated with the growth of M. aeruginosa under different nutrient levels. Overexpressed proteins related to photosynthesis and amino acid synthesis contributed to the stimulatory effects of increased nutrient supply in M. aeruginosa. Increased nitrogen supply directly promoted cyanobacterial growth through inducing the overexpression of the cell division regulatory protein (FtsZ). The transcriptional regulator NtcA that regulates gene transcription related to both nitrogen assimilation and microcystin synthesis was overexpressed under high nitrogen condition, which consequently induced overexpression of two microcystin synthetases (McyC and McyF) and promoted microcystin synthesis. Elevated nitrogen supply induced the overexpression of proteins involved in gas vesicle organization (GvpC and GvpW), which may increase the buoyancy of M. aeruginosa. Increased phosphorus level indirectly affected the growth and the synthesis of cellular substances in M. aeruginosa through the mediation of differentially expressed proteins related to carbon and phosphorus metabolism. This study provided a comprehensive description of changes in the proteome of M. aeruginosa in response to increased supply of two key nutrients.