Response of key stress-related genes of the seagrass <i>Posidonia oceanica</i> in the vicinity of submarine volcanic vents
Submarine volcanic vents are being used as natural laboratories to assess the effects of increased ocean acidity and carbon dioxide (CO<sub>2</sub>) concentration on marine organisms and communities. However, in the vicinity of volcanic vents other factors in addition to CO<sub>2&l...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-07-01
|
| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/4185/2015/bg-12-4185-2015.pdf |
| Summary: | Submarine volcanic vents are being used as natural laboratories to assess
the effects of increased ocean acidity and carbon dioxide (CO<sub>2</sub>)
concentration on marine organisms and communities. However, in the vicinity
of volcanic vents other factors in addition to CO<sub>2</sub>, which is the main
gaseous component of the emissions, may directly or indirectly confound the
biota responses to high CO<sub>2</sub>. Here we used for the first time the
expression of antioxidant and stress-related genes of the seagrass
<i>Posidonia oceanica</i> to assess the stress levels of the species. Our hypothesis is that unknown
factors are causing metabolic stress that may confound the putative effects
attributed to CO<sub>2</sub> enrichment only. We analyzed the expression of 35
antioxidant and stress-related genes of <i>P. oceanica</i> in the vicinity of submerged
volcanic vents located in the islands of Ischia and Panarea, Italy, and
compared them with those from control sites away from the influence of
vents. Reverse-transcription quantitative polymerase chain reaction
(RT-qPCR) was used to characterize gene expression patterns.
<br><br>
Fifty-one percent of genes analyzed showed significant expression changes.
Metal detoxification genes were mostly down-regulated in relation to
controls at both Ischia and Panarea, indicating that <i>P. oceanica</i> does not
increase the synthesis of heavy metal detoxification proteins in response to
the environmental conditions present at the two vents. The up-regulation of
genes involved in the free radical detoxification response (e.g., CAPX, SODCP
and GR) indicates that, in contrast with Ischia, <i>P. oceanica</i> at the Panarea site faces
stressors that result in the production of reactive oxygen species,
triggering antioxidant responses. In addition, heat shock proteins were also
activated at Panarea and not at Ischia. These proteins are activated to
adjust stress-accumulated misfolded proteins and prevent their aggregation
as a response to some stressors, not necessarily high temperature.
<br><br>
This is the first study analyzing the expression of target genes in marine
plants living near natural CO<sub>2</sub> vents. Our results call for contention
to the general claim of seagrasses as "winners" in a high-CO<sub>2</sub> world,
based on observations near volcanic vents. Careful consideration of
factors that are at play in natural vents sites other than CO<sub>2</sub> and
acidification is required. This study also constitutes a first step
for using stress-related genes as indicators of environmental pressures in a
changing ocean. |
|---|---|
| ISSN: | 1726-4170 1726-4189 |