128
reduction in these solutes. A recent study by Piro et al. (2015) pertains to the
response of Cymodocea nodosa to hypersalinity conditions (43 psu) over 30 days.
They observed through protein expression a decline in the expression of leaf proteins’ level in stressed plants. Additionally, a downregulation of structural PSI,
PSII proteins, and RuBisCO was illustrated. However, key enzymes involved in
glycolysis showed higher accumulation levels suggesting a change in carbon
metabolism in stressed plants (Piro et al. 2015). Moreover, the overexpression of
cytochrome b559, which is a necessary receptor for PSII, is an indication that
stressed plants in hypersaline conditions possess reparative mechanisms (Piro
et al. 2015). Their findings are in concordance with previous studies (Muramatsu
et al.2002; Kong et al. 2014) indicating that seagrasses in order to tolerate hypersaline conditions decrease photosynthetic conditions and increase osmoregulation
mechanisms.
6.4 Perspectives
The amount of the genomic information on seagrasses is increasing exponentially,
and the information on seagrass evolution and adaptation is contributing to improve
our understanding on how different species are expected to respond to abiotic stress
and adapt to the changing environment. New advances in systems biology holistic
approaches for gene discovery and functional genomics will give a deeper insight to
the molecular mechanisms that regulate the seagrass responses to tolerance acquisition to abiotic stress (Exadactylos 2015). In the Mediterranean Sea, for example,
Cymodocea nodosa, a euryhaline and eurythermal species, will adapt the global
change, while Posidonia oceanica, a stenothermal-stenohaline species, will decline.
The molecular approach of their adaptive tolerance mechanisms will help us to better understand their evolutionary trends, as well as to identify stress-related genes
and use the seagrasses as bioindicators of the ecosystem health.
There is a plethora of techniques that can be used to understand gene functions.
Functional genomics through gene manipulation have not yet been adopted in seagrasses in order to fully comprehend gene functions and networks. Among them,
gene knockdown is the foremost used technique in not only aquatic plants.
The CRISPR-Cas9 system, a flexible and robust technique for genome editing
to analyze the molecular basis of abiotic stress response, is considered nowadays
as the future solution for efficient and precise gene modifications which could in
a longer perspective lead to creation of abiotic stress-tolerant crop plants (Hsu
et al. 2014; Kumar and Jain 2015; Bortesi and Fischer 2015; Younis et al. 2014;
Jain 2015). RNA interference (RNAi) is another gene regulatory approach in
functional genomics. Recent studies have hinted possible roles of RNAi-related
processes in plant stress adaptation (IAASA, Pocket K No. 34 RNAi for Crop
Improvement, www.isaaa.org/resources/publications/pocketk/34/). Last but not
least, gene fusions to reporter genes such as green fluorescent protein (GFP) can
E.E. Malandrakis et al.
reduction in these solutes. A recent study by Piro et al. (2015) pertains to the
response of Cymodocea nodosa to hypersalinity conditions (43 psu) over 30 days.
They observed through protein expression a decline in the expression of leaf proteins’ level in stressed plants. Additionally, a downregulation of structural PSI,
PSII proteins, and RuBisCO was illustrated. However, key enzymes involved in
glycolysis showed higher accumulation levels suggesting a change in carbon
metabolism in stressed plants (Piro et al. 2015). Moreover, the overexpression of
cytochrome b559, which is a necessary receptor for PSII, is an indication that
stressed plants in hypersaline conditions possess reparative mechanisms (Piro
et al. 2015). Their findings are in concordance with previous studies (Muramatsu
et al.2002; Kong et al. 2014) indicating that seagrasses in order to tolerate hypersaline conditions decrease photosynthetic conditions and increase osmoregulation
mechanisms.
6.4 Perspectives
The amount of the genomic information on seagrasses is increasing exponentially,
and the information on seagrass evolution and adaptation is contributing to improve
our understanding on how different species are expected to respond to abiotic stress
and adapt to the changing environment. New advances in systems biology holistic
approaches for gene discovery and functional genomics will give a deeper insight to
the molecular mechanisms that regulate the seagrass responses to tolerance acquisition to abiotic stress (Exadactylos 2015). In the Mediterranean Sea, for example,
Cymodocea nodosa, a euryhaline and eurythermal species, will adapt the global
change, while Posidonia oceanica, a stenothermal-stenohaline species, will decline.
The molecular approach of their adaptive tolerance mechanisms will help us to better understand their evolutionary trends, as well as to identify stress-related genes
and use the seagrasses as bioindicators of the ecosystem health.
There is a plethora of techniques that can be used to understand gene functions.
Functional genomics through gene manipulation have not yet been adopted in seagrasses in order to fully comprehend gene functions and networks. Among them,
gene knockdown is the foremost used technique in not only aquatic plants.
The CRISPR-Cas9 system, a flexible and robust technique for genome editing
to analyze the molecular basis of abiotic stress response, is considered nowadays
as the future solution for efficient and precise gene modifications which could in
a longer perspective lead to creation of abiotic stress-tolerant crop plants (Hsu
et al. 2014; Kumar and Jain 2015; Bortesi and Fischer 2015; Younis et al. 2014;
Jain 2015). RNA interference (RNAi) is another gene regulatory approach in
functional genomics. Recent studies have hinted possible roles of RNAi-related
processes in plant stress adaptation (IAASA, Pocket K No. 34 RNAi for Crop
Improvement, www.isaaa.org/resources/publications/pocketk/34/). Last but not
least, gene fusions to reporter genes such as green fluorescent protein (GFP) can
E.E. Malandrakis et al.