Environmental and Economical Opportunities for the Valorisation of the Genus Atriplex: New Insights - Crop Improvement: New Approaches and Modern Techniques - page 447

Xu et al. ( 2011 ) investigate the physiological responses and differential gene
expression caused by salinity exposure in A. centralasiatica plants grown from
two different seed morphs. A. centralasiatica widely distributed in China produce
tow type of seeds, yellow and brown seeds. Seedlings derived from yellow seeds
showed a greater salt tolerance than those derived from brown seeds. By using sup-
pression subtractive hybridization (SSH) and subsequent microarray and RT-PCR
analysis to isolate and compare genes that were differentially expressed, the authors
suggest a major contribution of gene regulation to the salt resistant phenotype of
seedlings derived from yellow seeds. These genes encoded proteins related to os-
motic and ionic homeostasis, redox equilibrium and signal transduction. This study
clearly links physiological responses with differential gene expression in seedlings
derived from dimorphic seeds. Such dimorphism offers the advantage to halophytic
plants to survive in highly variable environments.
Conclusion and Future Perspective
The global distribution of the genus Atriplex in arid and semi-arid areas and its abi-
otic stress tolerance combined with the utility of Atriplex species for restoration, re-
mediation and forage for livestock have helped these plants to rank among the most
widely studied native halophytes species. The major limitation of use Atriplex in
livestock production is its high salt concentration. Atriplex species are best consid-
ered as a supplement rather forage. The plant used for these purposes are primarily
wild type and there are little information available on the nutritive value of Atriplex
species growing in greenhouse and irrigated with different concentration of NaCl.
Strategies need to be devised to minimize the salt contents in the Atriplex leaves.
Although the biochemistry of Atriplex species tends to establish that they may be
a source of novel compounds along with providing a new source for many already
know biologically active compounds. Data of chemical composition of Atriplex
species is still not completed.
Atriplex species are well adapted to both salt and drought stress and can serve
as model species to understand the mechanisms of tolerance in plant (Flowers and
Colmer 2008 ). Very little research has been carried out to identify the molecular
mechanisms directly responsible for the specific tolerance of Atriplex species to
abiotic stress. In this way, Atriplex may serve as a particularly useful model plant
for studies of regulatory mechanisms related to the activation of the GB biosyn-
thetic pathway in response to environmental stress.
With over 400 species of this genus, a significant opportunity then exists to ex-
plore the potential of other locally adapted Atriplex species. Research is required to
select and breed potentially useful plants and identify the best species combining
nutritional, agronomic and environmental potential.
Acknowledgments This work was supported by the Tunisian Ministry of Higher Education and
Scientific Research (LR10CBBC02).