Exogenous Trehalose Improve Arabidopsis Thaliana Salt Tolerance

Salinity tolerance is a complex phenomenon, brought about an adaptation in a range of physiological processes. Abiotic stresses can directly or indirectly affect plant growth and crop production. To survive against the stresses, such as drought, salinity, and low-temperature, plants respond and adapt with complex mechanisms, including developmental, morphological, physiological, and biochemical strategies. High salinity is one of the most severe abiotic stress, plants have developed a complex defense system, including ion homeostasis, osmolyte biosynthesis, compartmentation of toxic ions, and reactive oxygen species (ROS) scavenging systems.Trehalose is a non-reducing disaccharide, which is found widely in nature. In bacteria, fungi, and insects, the functions of trehalose are a storage carbohydrate and protects against a variety of stresses, but it is trace in higher plants. Some papers had reported that trehalose could improve drought stress effectively, but the reports about the relationship of trehalose and salt stress are little, in addition to the physiological mechanism of improving salt stress is not clear. In our studies, exogenous appropriate trehalose improved high salt tolerance in Arabidopsis thaliana (Col-0) either younger or mature seedlings. Through improving inflorescence rate, inflorescence length and increasing shoot fresh weight, leaf water content to make the seedlings grow better under salt stress. Most abiotic stress signal is the generation of reactive oxygen species (ROS). Trehalose could be available to scavenge ROS by increasing the activities of antioxidant enzyme such as POD, APX, CAT and SOD in leave tissues to antagonise high salt-stress. In addition, we found that the role of trehalose is important to maintain K+ / Na+ homeostasis at the aspect of salt tolerance. Exogenous trehalose could decrease Na+ content and reduce the K+ loss in the leaves and IS (inflorescence stems) in order to maintain K+ / Na+ homeostasis and resistance to salt stress. When the degree of salt poisoning is different, the mechanism of exogenous trehalose is distinguishing in improving the plants salt tolerance. In our studies of osmotic materials, the result showed that lower salt stress made the soluble sugar content decreas, while the soluble sugar content increased under higher salt condition, for example glucose and sucrose. Exogenous trehalose can effectively improve the changes reduced by salt poisoning. But the physiological mechanism is not very clear, still need further study on the relevance of trehalose and osmoregulation.So, current data suggest that appropriate concentration of trehalose effectively improve the salt tolerance in wild type Arabidopsis (Col-0), and it is indicated that 1mM trehalose was the most effective. In addition to, the result is different to that of the similar experiments with sucrose which is also one of non-reducing disaccharide. The corresponding concentration of sucrose was not valid to improve the plant salt tolerance.