Relationships of Vibrio Species
Infection and Elevated Temperatures
to Yellow Blotch/Band Disease in
Caribbean Corals
JM Cervino, RL Hayes, SW Polson, SC
Polson, TJ Goreau, RG Martinez, and
GW Smith
Appl. Environ. Micro. 70:6855-6864.
Importance of Corals Reefs
• Coral reefs maintain high levels of
biodiversity.
• Provide habitats for coastal fisheries.
• May contain potential pharmacological
compounds.
• Protect shorelines from erosion.
• Tourism
Corals Affecting Diseases
• The known major coral diseases under study are
Black Band Disease, Coral Bleaching,
Discoloring Spots, Red Band Disease, White
Band Disease, White Plague Disease, White
Pox Disease and Yellow Blotch/Band Disease.
• During the last 10 years, the frequency of coral
diseases appears to have increased
dramatically.
• Most diseases occur in response to the onset of
bacteria, fungi, and viruses.
Microorganisms Associated
Diseases
• Aspergillus sydowii and a gram negative
rod-shaped bacterium in the genus
Sphingomonas : cause white plague
• Serratia marcescens: cause white-pox
disease.
Corals Affecting Diseases
• Phormidium corallyticum, a consortium of
microorganisms are present in the black
band disease, contribute to the loss of
coral tissue.
• A number of Vibrio species may be related
with white band disease.
Effects of These Diseases
• Diseases can alter the reproductive potential of
a population.
• Alter interactions among populations.
• Cause mortalities, leading to changes in
ecosystem composition, structure, processes,
function.
• A key effect of a disturbed coral is the expulsion
zooxanthellae. It can be triggered by disease as
well as by thermal stress, among others.
A zooxant…what?
• Unicellular algae which live symbiotically
in the gastrodermis of reef-building corals.
• Nutrients supplied by the zooxanthellae
make it possible for the corals to grow and
reproduce quickly enough to create reefs.
• Provide the corals with nutrients.
In turn, the coral provides
protection and access to light.
• Give corals their color.
• Affect composition of mucous
and the bacteria on it.
Yellow Blotch/Band Disease (YBD)
• Affects massive reef building corals Montastraea
spp.
• First documented in the lower Florida Keys.
• Known to occur throughout the Caribbean.
• Can spread across a coral colony at ~0.5-1.0
cm/month.
• Causes zooxanthellae
loss.
Research Goals
• Show the effects of temperature and
inoculation with exogenous Vibrio strains
on division rates of zooxanthellae
symbionts.
• Show how this results in low symbiont
densities and decreased chlorophyll
concentrations in the corals.
Methods and Results
• Microbial Analysis
– Took samples from healthy and YBD-infected
Montastraea spp.
– Sample plated out, 143 pure cultures isolated, 35
from healthy corals samples and 79 from diseased
corals samples.
– Samples were compared based on carbon utilization
patterns.
– Sixteen bacterial isolates were chosen, 6 from
healthy corals (controls) and 10 present only in
diseased corals.
Methods and Results
• Infection Experiments
– Preliminary testing- bacterial isolates from diseased
corals were inoculated onto health corals tissue in
different combinations, all resulted in tissue paling.
This was not the case with control isolates.
– Only the 10-strain mix caused yellow lesions
– Isolates were identified by sequence analysis of the
16S rRNA gene.
– Sequencing showed 4 different Vibrio species.
– When the 4 bacteria were smeared together on the
coral, YBD lesions appeared.
Methods and Results
• Coupled effects of YBD infected corals
and variation in temperature.
Methods and Results
Microscopy, cell densities, mitotic
index and pigment analysis
Microscopy, cell densities, mitotic index and
pigment analysis
Microscopy, cell densities, mitotic index and
pigment analysis
Conclusions
• Yellow Band Disease primarily affects
zooxanthellae and secondarily host tissue.
• This seems to be caused by isolated vibrios.
• These isolates seem to act as a consortium.
• Stronger effects were shown when temperature
increased.
• The symbiotic zooxanthellae appear to be
degraded inside of the coral tissue instead of
being expelled.
Future Research
• Biochemical characterization of virulence
factors of the isolates.
• Compare this factors with closely related
vibrios.
• Use on non-culture dependent methods.
Questions??