Unlocking the functional potential of Red Sea coral probiotics

One of the key components promoting coral homeostasis is their association with microorganisms from different phylogenetic groups, including microalgae, bacteria, and viruses, which, together with the host, form the coral holobiont. Bacterial symbionts have drawn the scientific community's attention among coral-associated microbes because of their critical roles in host metabolism and health. However, many questions remain regarding their ecological roles in coral physiology and ecosystem functioning. In the Red Sea, the large coral diversity and unique conditions combining high temperature and high salinity make this basin a suitable model environment for ecological surveys and studies about the future of coral reefs under climate change scenarios. After investigating the coral microbiome composition of healthy coral species in the Red Sea, by using culture-dependent techniques, over 300 bacterial strains were isolated. From those, six strains were selected due to their ability to synthesize catalase - known to cancel the toxic action of reactive oxygen species - and to fixate nitrogen, and identified as Pseudoalteromonas galatheae (n=2), Cobetia amphilecti (n=2), Halomonas sp. (n=1), and Sutcliffiella sp. (n=1). High-quality DNA extracted from these strains was sent for whole-genome sequencing using Pacbio and further assembled and screened for genes of interest using several platforms and databases (e.g., BV-BRC, Prokka, Roary). Identifying promising proteins, enzymes, and beneficial traits or functions may help us select putative functions associated with the beneficial roles of coral-associated microbes.