Genetics of Coral Reefs

By: Jack Bush

Credits: Pacific Stock for Kensington 

Gammaproteobacteria is a class in the Proteobacteria phylum that contains bacteria that are medically, ecologically, and scientifically important. Throughout this study, GacA is a regulatory bacterium that directs the expressions of csr small regulatory RNAs that control genes with carbon metabolism functions, motility, biofilm formation, and virulence. The studied pathogen was Serratia marcescens. This pathogen can infect several plants, invertebrates, and vertebrates. Serratia marcescens PDL100 is a coral necrotizing pathogen associated with white pox disease in the coral Acropora palmata (Kredit et al., 2013). Very little is known about the virulence mechanisms on which this pathogen relies to infect corals.

The conservation of coral is essential in today’s world and this type of research can directly contribute to the preservation of them, because the ocean is a major carbon sink and coral reefs participate in these processes, protect these coral reefs is essential.

This article helps conservation efforts towards different types of corals. I think more research on the different virulence of coral is needed. Still, this start into looking at how a particular bacterium affects coral is vital to show that these bacteria do have impacts. The conservation of coral is essential in today’s world. This type of research can directly contribute to preserving them because the ocean is a major carbon sink; therefore, the protection of coral reefs is essential. Factors that will either harm or help these bacteria are crucial pieces of information that need to be gathered to make educated decisions when deciding how to protect these corals and treat them if they become sick.


Figure 1. (Kredit et al., 2013) The importance of gacA regulation of metabolism for growth of S. marcescens on coral mucus. His shows the competitive fitness of the different types of coral. 
The swarming phenotype was complemented by the plasmid borne gacA, while a pBBR1-MCS5 vector did not alter the swarming behavior of the mutant(Kredit et al., 2013).

GacA was found to regulate swarming motility and biofilm formation and be capable of surface spreading but with an altered architecture of the swarm colony. This was found to lack three-dimensionality and extensive dendritic patterns. The swarming phenotype was complemented by the plasmid-borne gacA, while a pBBR1-MCS5 vector did not alter the swarming behavior of the mutant (Kredit et al., 2013). After 72h of incubation, biofilms stained with crystal violet were significantly reduced in the gacA mutant compared with the wild type. Like that in the swarming phenotype, complementation with the wild-type copy of gacA fully restored biofilm formation to wild-type levels. The addition of the empty pBBR1 vector did not affect biofilm formation in the gacA mutant.


Learn More (Citations):


Kredit C, Caprinone E, Ritchie K & Teplitski M. (2013). “Characterization of the gacA-dependent surface and coral mucus colonization by an opportunistic coral pathogen Serratia marcescens PDL100.” FEMS. 84: 290-301.

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