Comparative Metagenomics Highlight a Widespread Pathway Involved in Catabolism of Phosphonates in Marine and Terrestrial Serpentinizing Ecosystems

Frouin et al. (2022) found that serpentinizing systems tend to be colonized by diverse communities, and that bacterial groups encountered often include acetogens (Firmicutes) and methanogens like Methanosarcinales (Archaea), as originally discovered at Lost City.

“They found that serpentinizing systems tend to be colonized by diverse communities, and that bacterial groups encountered often include acetogens (Firmicutes) and methanogens like Methanosarcinales (Archaea), as originally discovered at Lost City.”

Frouin et al. (2022) found that Prony Bay was dominated by the acetogen Bipolaricaulota, which was also the main inhabitant of the Oman ophiolite community recently characterized by Colman et al. (2022).

“Frouin et al. (2022) found that Prony Bay was dominated by the acetogen Bipolaricaulota, which was also the main inhabitant of the Oman ophiolite community recently characterized by Colman et al. (2022) on the other side of the globe.”

Most studies have detected nitrogenase genes among the microbiota of serpentinizing systems, though nitrate reduction can also be detected.

“Most studies have detected nitrogenase genes among the microbiota of serpentinizing systems, though nitrate reduction can also be detected (Frouin et al., 2022).”

Frouin et al. (2022) estimate that about half of the microbes that they sampled from Prony Bay possess the genes required for the metabolism of phosphonates and they found that phosphonate metabolism was fairly common in microbial communities from serpentinizing systems.

“They estimate that about half of the microbes that they sampled from Prony Bay possess the genes required for the metabolism of phosphonates and they found that phosphonate metabolism was fairly common in microbial communities from serpentinizing systems.”

While about half of the genomes from the Prony Bay vents contained genes related to phosphonate metabolism, metabolizing operons represent a frequency that is significantly higher than average for marine microbes, it is not orders of magnitude higher: up to 30% of marine microbial genomes have the potential for phosphonate degradation.

“While about half of the genomes from the Prony Bay vents contained genes related to phosphonate metabolism, metabolizing operons represent a frequency that is significantly higher than average for marine microbes (Frouin et al., 2022), it is not orders of magnitude higher: up to 30 % of marine microbial genomes have the potential for phosphonate degradation (Acker et al., 2022).”

In some of the Prony Bay metagenomes, the gene for an additional enzyme, NAD+-dependent phosphite oxidoreductase, ptxD, was often inserted into the phosphonate metabolizing operon.

“Moreover, in some of the Prony Bay metagenomes, the gene for an additional enzyme, NAD+-dependent phosphite oxidoreductase, ptxD, was often inserted into the phosphonate metabolizing operon (Frouin et al., 2022).”

Frouin et al. (2022) looked carefully at sources and pathways for nitrogen but found no consistent trend.

“Frouin et al. (2022) looked carefully at sources and pathways for nitrogen but found no consistent trend.”

Frouin et al. (2022) noted the ability of Prony Bay microbes to utilize reduced phosphorous compounds.

“Frouin et al. (2022) noted the ability of Prony Bay microbes to utilize reduced phosphorous compounds.”

The recent findings of Frouin et al. (2022) from Prony Bay place the phosphate problem in a fundamentally different light.

“The recent findings of Frouin et al. (2022) from Prony Bay place the phosphate problem in a fundamentally different light.”

There is phosphite available in serpentinizing systems and microbes that live there are using it.

“The implications of i) genes for phosphite oxidation being present in microbes from serpentinizing systems (Frouin et al., 2022) and ii) phosphite being a component of rock in serpentinizing hydrothermal systems (Pasek et al., 2022) suggest that there is phosphite available in serpentinizing systems and that microbes that live there are using it.”