The Functional Research Of Thellungiella Halophila TRXh And Arabidopsis Thaliana TRXh

The plant was subjected to various stresses inevitably in its lifecycle, such as the salt, drought, low temperatureetc. in the early stage , the ion became imbalant.the aggravation of these stresses were often accompanied with ROS and the secondary oxidize stress. The living creature can regulate the redox state through a variety of paths or ways, and the regulation with thioredoxin is a way of these kinds.Thioredoxins, a small ubiquitous, heat-stable, acidulous proteins with a redox active disulfide bridge in its conserved motif -WCP(G)PC-, distribute universally in prokaryote and eukaryote(animals, plants, bacteria, archaea etc.) and have a molecular mass of approximately 12Kda. They are a sort of redox regulation proteins, which play an important role in regulating various physiological reactions related to redox status in cells. By the disulfide/dithiol interchange reaction, Thioredoxins can transmit electrons and protons, therefore can transmit the regulatory redox signals to selected targets (enzymes, proteins, transcription factors etc) and effect many processes.Thioredoxins ,considered as some key enzyme in the photosynthesis ,was discovered in the chloroplast at fist,afterward had also discovered in the cytoplasm and the plastochondria.Since several dozens years, the people had an understanding of its type, characteristic, function, and set the foundation to use it.Thellungiella halophila is close relative to Arabidopsis which is also belong to Cruciferae and has good genetic features such as similar morphology, small genome size, short life cycle, high seed number and an efficient transformation method. However, Thellungiella halophila is able to withstand dramatic salinity shock up to 500mM NaCl. This plant does not produce salt glands or other complex morphological alterations either before or after salt adaptation. Therefore, the study of function of thioredoxin from Thellungiella halophila is quite significant for expatiating plant response mechanism of oxidative stress, understanding the metabolism alteration and adjustment of plant under stresses and expounding the stress tolerance metabolism.Since family members of TRXh exist not only in cytoplasm but also in Endoplasmic reticulum and mitochondria, and different localizations affect their potential functions. In order to understand that ThTRXh the biology function, we first constructed ThTRXh-GST vector, then expressed amalgamation protein in DE3 Ecol, provided the condition for further research. At the same time ,by constructing the GFP expression vector of ThTRXh and transforming it into the Arabidopsis anthotaxy, ThTRXh is mostly localized in cytoplasm membrane by laser scanning confocal microscope,after the transgene strain was processed by different salty, the oxidative stress .AtTRXh mutant were ordered from the salk library and the phenotype of the mutant and ThTRXh-overexpression Arabidopsis plants was analyzed to set the foundation for the following work of mutant phenotype complementation. Our results showed that the germination rate of mutant was much lower than that of the wild type,and the germination ratio of transgenic plants was higher than that of the wild type in medium containing H2O2. These results demonstrated that thioredoxin h involved in seed germination . It might act as a kind of massager in plant oxidative stress response.