Evidence for phosphonate usage in the coral holobiont

Area of Science:

• Marine microbiology
• Biochemistry
• Genomics

Background:

• Phosphonates, featuring a stable carbon-phosphorus bond, are vital components of invertebrate cell membranes.
• Phosphonoacetate hydrolase (phnA) is the enzyme responsible for cleaving phosphonoacetate into acetate and phosphate.

Purpose of the Study:

• To investigate the diversity and distribution of the phnA gene in bacteria associated with coral holobionts.
• To explore the role of phosphonates in marine ecosystems.

Main Methods:

• Screening of eight coral species for the phnA gene using degenerate primers.
• Sequencing of the phnA gene in soft corals (Sinularia and Discosoma).
• Isolation and genotypic analysis (phnA+) of bacterial taxa utilizing phosphonoacetate.

Main Results:

• The phnA gene was detected in the holobiont of all eight coral species tested.
• Sequencing revealed 13 distinct groups of phnA genes in two soft coral species based on 90% sequence identity.
• Sixteen bacterial taxa were isolated, with 8 possessing a phnA+ genotype and capable of using phosphonoacetate as a sole carbon and phosphorus source.

Conclusions:

• There is unusually high diversity of the phnA gene in coral-associated bacteria.
• The findings underscore the widespread occurrence and ecological importance of phosphonates in marine environments.