Study finds deep-sea non-photosynthetic bacteria sense blue light through blue light receptors

Recently, Sun Chaomin's research group from the Institute of Oceanography, Chinese Academy of Sciences discovered that non-photosynthetic bacteria in deep-sea cold springs sense blue light through blue-light sensing proteins and stimulate energy synthesis, providing another example for deep-sea microorganisms to sense and utilize light energy
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Numerous studies have confirmed that the growth of photosphere organisms is more or less affected by light
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But deep-sea habitats have long been viewed by researchers as a dark, chemically powered ecosystem
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But there is growing evidence that different forms of geoluminescence or bioluminescence exist not only in deep-sea hydrothermal areas, but also in other deep-sea habitats such as cold springs
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Studies have shown that nearly 80% of deep-sea animals can emit light, mainly in the form of blue light
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Many microbiologists have also been exploring whether deep-sea microbes can sense and even use blue light or other wavelengths of light
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However, due to the difficulty of deep-sea sample collection and the difficulty of culturing deep-sea microorganisms, the above problems have not been effectively solved
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 The study was based on the sediment collected by the "Science" in 2017 near a cold spring vent in the deep-sea waters of the South China Sea.
A blue-light enrichment culture technique was used to obtain a spongy bacillus from the sediment sample
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The study found that the strain achieved the fastest growth rate under blue light (470 nm) illumination compared to other types of light
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However, genome sequencing showed that the strain did not contain the chlorophyll synthesis pathway and the rhodopsin-encoding gene, and did not belong to the common type of light energy utilization
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The proteome results showed that the bacterial blue light sensing protein BLUF plays an important role in the process of sensing blue light.
The gene encoding BLUF was knocked out by molecular genetics, and it was found that the ability of the bacteria to sense blue light was significantly weakened, which further verified the proteome.
Consistent with the results of the in vivo experiments, the blue light protein expressed in vitro also showed obvious blue light sensing activity
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 The above proteomic, genetic and biochemical experimental results comprehensively confirmed that the blue light-sensing protein BLUF mediates the perception of blue light in deep-sea bacteria, and further activates the synthesis pathway of acetyl-CoA, thereby significantly enhancing the tricarboxylic acid cycle pathway and energy production.
Finally, the rapid growth of the strain is promoted
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It is worth noting that the homologous protein of the blue light receptor BLUF is widely distributed in deep-sea microorganisms, indicating that many microorganisms from deep-sea sources can also sense and utilize blue light through a similar pathway, and it also suggests that microbiologists need to consider microbial mediation in future research.
Contribution of guided light energy metabolism to energy cycling in deep-sea ecosystems
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 The related results were published in mSystems under the title of A deep sea bacterium senses blue light via a BLUF dependent pathway
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The research was jointly funded by the Strategic Pilot Science and Technology Project of the Chinese Academy of Sciences and the Frontier Key Deployment of the Ocean Science Center of the Chinese Academy of Sciences
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 BLUF mediates deep-sea bacteria sensing blue light and activating energy synthesis pathways Source: Institute of Oceanography, Chinese Academy of Sciences