Complementarity in the Coral Holobiont: A Genomic Analysis of Bacterial Isolates of Orbicella faveolata and Symbiodinium spp.

Open Access
Smith, Styles Michael
Graduate Program:
Master of Science
Document Type:
Master Thesis
Date of Defense:
July 09, 2018
Committee Members:
  • Monica Medina, Thesis Advisor
  • Stephen Wade Schaeffer, Committee Member
  • Kevin Loren Hockett, Committee Member
  • coral holobiont
  • nutrient cycling
  • DMSP
  • cobalamin
  • denitrification
All holobionts, defined as a multicellular host and all of its associated microorganisms, rely on interactions between its members. Corals, which demonstrate a strong symbiosis with an algal partner, have a diverse holobiont that can be sequenced and analyzed that could reveal important roles of microbes that benefit its health. This microbial community has been predicted to be composed of nitrogen fixers, phototrophs, sulfur and phosphorus cyclers. However, the identity of these microbes responsible for these roles remain uncertain. In addition, there may be complementary roles that are unknown. Predicting these roles is challenging because…. A suggested method to overcome this problem is sequencing the genomes of the microbes found in the coral holobiont. I hypothesize that bacterial members of the holobiont play an important role in coral biology via complementary metabolisms in nutrient cycling and aiding the coral in stress response. The complete metabolic capabilities of ten bacteria isolated from the coral holobiont were examined via the sequencing and annotation of the whole genome, followed by pangenomic analysis with 31 whole genomes of closely related strains of bacteria previously sequenced. The metabolisms identified—including denitrification, dimethylsulfoniopropionate biosynthesis and degradation, and cobalamin biosynthesis—potentially complement the coral holobiont via nutrient cycling. These findings demonstrate the importance of genomic sequencing to reveal the interactions between members of the holobiont.