Nature Microbiology Zhang Yuzhong's team at Ocean University of China reveals a new mechanism of marine bacteria's organic sulfur metabolism and defense

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iNature When the algae is preyed, the ruptured algae releases dimethyl sulfopropionate (DMSP) through cracking to produce a high concentration of toxic acrylic acid, which resists further predation by algae-eating zooplankton.
However, it is not clear that marine bacteria Whether there are parallel defense mechanisms in the system
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 On October 25, 2021, Zhang Yuzhong’s team from Ocean University of China published a research paper entitled "Acrylate protects a marine bacterium from grazing by a ciliate predator" in Nature Microbiology, which proved that the marine bacterium Puniceibacterium antarcticum does not use DMSP as a carbon source.
SM1211 has a membrane-related DMSP lyase DddL
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Under high concentration of DMSP, DddL degrades DMSP to cause the accumulation of acrylate around the cells, thereby preventing the predation of the marine ciliates Uronema marinum, and allowing the ciliates to transfer the predation pressure to the bacteria in the community that do not contain the dddL gene.
Competitive advantages in resources and space
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In short, this research system reveals a new mechanism for marine bacteria to use DMSP as a precursor to play a predator-predator function, laying a foundation for in-depth exploration of the interactions between organisms in marine micro-ecosystems
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Predation and defense are important predator-prey interactions in the field of microorganisms
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Chemical defense strategies are common in marine environments
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DMSP is one of the most abundant organic sulfur compounds in marine ecosystems.
It is synthesized by a series of marine phytoplankton and bacteria.
The concentration ranges from low nanomolar in open sea water to hundreds of millimolar in phytoplankton
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 Although DMSP lysis plays an important ecological role in preventing herbivores in eukaryotic algae that produce DMSP, whether there are parallel systems in marine bacteria remains elusive
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In this study, the chemical defense strategy of marine bacteria was reported to prevent predation by protozoa using DMSP as a precursor compound
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Figure: The chemical defense strategy of the marine bacterium Puniceibacterium antarcticum SM1211 with DMSP as the precursor material (picture from Nature Microbiology) This study proved that the marine bacterium Puniceibacterium antarcticum SM1211, which does not use DMSP as a carbon source, has the membrane-related DMSP lyase DddL
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 Under high concentration of DMSP, DddL degrades DMSP to cause the accumulation of acrylate around the cell, thereby preventing the predation of marine ciliates Uronema marinum, and allowing the ciliates to transfer predation pressure to bacteria in the community that do not contain dddL genes, thereby obtaining Competitive advantages in resources and space
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In short, this research system reveals a new mechanism for marine bacteria to use DMSP as a precursor to play a predator-predator function, laying a foundation for in-depth exploration of the interactions between organisms in marine micro-ecosystems
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