Basic HTML Version
International Journal of Marine Science 2014, Vol.4, No.50, 1-22
http://ijms.biopublisher.ca
8
2 Discussion
From a collective assessment of the data obtained
herein and in prior works (Table 3), it appears that
S.
hystrix
colonies from Houbihu (UWS), Southern Taiwan
do not demonstrate a pronounced mRNA-level response
to a temperature hypothesized to induce stress, 30
℃
.
Specifically, expression of none of the six
Symbiodinium
genes spanning three cellular processes;
Table 3
.
Summary of results.
No coral colonies of the elevated temperature experiment (ETE) or nubbins of the variable
temperature experiment (VTE) died over the course of the experiments, and for the ETE, in which only a small proportion of the 18
colonies was sacrificed for molecular analyses, the remaining colonies survived under ambient conditions at NMMBA for at least six
months after the termination of the experiment.
ETE
VTE
Physiology
temperature time
interaction temperature
site of origin
interaction
survival
growth
(mg cm
-2
day
-1
)
NA
*
Symbiodinium
density
(cells cm
-2
)
NA
*
chlorophyll a concentration
(pg cell
-1
)
NA
*
*
maximum quantum yield of PSII
(F
V
/F
M
)
NA
*
*
Molecular composition
Symbiodinium hsp70
GCP
*
RNA/DNA ratio
protein/DNA ratio
*
*
Symbiodinium
genotype
host coral genotype
NA
Gene expression
Gene
Compartment Function
Solaris spike recovery
exogenous spike
*
rbcL
Symbiodinium
photosynthesis
*
psI
Symbiodinium
photosynthesis
*
*
pgpase
Symbiodinium
photosynthesis
*
nrt2
Symbiodinium
metabolism
apx1
Symbiodinium
stress response
hsp70
Symbiodinium
stress response
*
*
hsp70
host
stress response
*
*
actb
host
cytoskeleton
*
*
trp1
host
cytoskeleton
tuba
host
cytoskeleton
*
ezrin
host
cytoskeleton
cplap2
host
osmoregulation
*
oatp
host
osmoregulation
trcc
host
osmoregulation
Note: *
p
<0.05. “NA” = not assessed.
photosynthesis, metabolism, and the stress response,
differed between treatments at any sampling time in
the ETE. On the other hand, expression of host
tuba
decreased 2-fold from the 24 to the 48 h sampling
time in the high temperature samples. Although such a
decrease could provide evidence in support of the
hypothesis that the coral cytoskeleton may become
compromised
under
potentially
stress-inducing
conditions (Mayfield and Gates, 2007), a similar
change in only one other target gene was observed;
actb
was also expressed at higher levels in controls
relative to high temperature samples at the final
sampling time, though this difference was not
statistically significant. It should be noted that
actb