Study On Physiological Response Of Defected N-glycosylation In Thellungiella Halophila Under Salinity Stress

Salinity stress is a major abiotic factor that affects plant growth and yield and the effective way to solve this problem is increasing the capability of salt tolerance of plants.Since salt tolerance is a trait which is controlled by multiple genes and sophisticated regulatory mechanisms,the improvement of plant salt tolerance through operation on a specific gene is always far from expectation.Asparagine(N)-linked glycosylation of proteins is one of the most crucial post-translational modifications in eukaryotic cells.In Arabidopsis thaliana,several genes involved in N-glycosylation such as the genes coding STT3a,the catalytic subunit of oligosaccharyltransferase and 1,2-N-acetylglucosaminyltransferase I,GnTI,have been proved to be involved in regulation of roots response to salt stress.The halophyte Thellungiella halophila,a close relative of Arabidopsis thaliana,is used as a model for the study of salt tolerance in plants because of many similar morphology and genetics features with Arabidopsis thaliana.In current study,using RNA silencing method I knockout the expression of STT3A and CGL1 in Thellungiella and some physiological indexes related to abiological stress including MDA,proline chlorophyll content,and antioxidant enzyme(SOD,POD,CAT)activity and the expression of salt stress sensitive gene(such as SOS1),were measured and analyzed under high dose of salinity.The results showed that Thellungiella RNAi mutants had considerable decrease on the level of basal metabolism and the degree of response.The adaptation and tolerance against salt of STT3A and CGL1 Thellungiella RNAi lines were much reduced as well.My work indicated the defective glycosylation functions had the negative effects on salt response and the N-glycosylation of protein is indispencible on the maintaince of the salt tolerance in halophytes.