THE POSSIBLE ROLE OF PHYTOENE SYNTHASE IN THE SALINITY TOLERANCE OF Salicornia iranica

Salinity is one of the most severe abiotic environmental stresses causing extensive crop loss worldwide. Despite all-embracing literature there are still debates about the mechanisms imparting tolerance against the salt stress. Salicornia species with their extreme salt tolerance make the ideal model plants for delving into the mechanisms they use to overcome high salt concentrations. On the other hand, many evidences suggested that metabolic engineering of carotenoid biosynthesis would improve tolerance of plants to saline condition. In halophytic Salicornia iranica, however, the role of Phytoene synthase (PSY), a key enzyme in carotenoid biosynthetic pathway, is still unclear. The main objectives of this study were first to identify the best growth condition for S. iranica and secondly to shed light on the possible relationship between SiPSY of carotenoid pathway and salt tolerance in S. iranica. So, growth parameters such as shoot and root length and weight, number of branches, shoot internodes, seed production, and chlorophyll content of the plants were measured in different salt concentration. In addition, transcript of SiPSY was measured by Real-Time qRT PCR under different salinity stresses. Analysis of NaCl tolerance showed the best growth condition for S. iranica at 200 mM NaCl. One of the more significant findings to emerge from this study is the potential role for SiPSY in imparting salt tolerance in S. iranica. It is possible to hypothesis that SiPSY may serve as potential target for engineering salinity tolerance in crop plants.