Regulation Mechanism Of An Ethylene Response Factor Gene, ThERF1, From Tamarix Hispida In Response To High-salt Sress

ERF transcription factors are a class of plant-specific transcription factor, which belongs a subfamily of AP2/ERF family. ERF transcription factors can regulate the expression of downstream genes by binding to the GCC-box and DRE element, and then regulate plants in response to biotic and abiotic stresses.We had coled16ERF genes with full ORF from the transcriptoms of Tamarix plant. The expression patterns of these16ThERF genes under the stress of drought, salt and ABA were studied by using quantitative real-time PCR. The result showed that all the expressions of these genes were all changed significantly, indicating that these ThERF genes may be involved in responses to stresses and ABA signaling pathway.pROKII-ThERFl-GFP fusion expression vector was created to study the subcellular localization of ThERF1by using particle bombardment. The result showed that the ThERFl was localized in the nucleus.Stress tolerance analysis of transgenic Arabidopsis were performed, including determination of the germination rates and the growth of transgenic Arabidopsis and wild-type Arabidopsis; anlysis of ROS level and the damage of cell membrane in plants by histochemical staining methods; measuring physiological parameters and expression of SOD, POD genes. The results showed that the germination rate and growth of transgenic line were lower than that of wild-type Arabidopsis under drought and salt stress, and ROS level and cell membrane damage in transgenic line were higher than in wild-type Arabidopsis, indicating that the transgenic Arabidopsis plants showed decreased stress tolerance in relation to wild-type Arabidopsis; determination of the physiological changes like SOD and POD activity, MDA content, chlorophyll content, leakage of electrolyte and H2O2content in plants under drought, salt and ABA treatment; the expression of SOD and POD in transgenic plants were highly decreased in relation to WT plants under drought, salt and ABA stress, which verified the previous results of physiological indicators measuring.Seven ThERFs homologous with ThERFl were cloned from the transcriptoms of T. hispida, and were used in analysis of formation of homodimers or heterodimers with ThERF1using the yeast two-hybrid system. The result showed that ThERF1not only can form homodimers with itself, but also form heterodimers with ThERF4, ThERF11and ThERF16to funtion.Three stress-related cis-acting elements, including GCC-box, W-box and MBS, were found in the promoter of ThERFl, and the upstream regulatory factors that can bind to these cis-acting elements were studied by using the yeast one-hybrid technology. The result showed that ThERF10can bind to GCC-box specifically, ThWRKY2and ThWRKY8bind to W-box specifically, meanwhile ThMYB2and ThMYB9bind to MBS specifically.Cis-acting elements recognized by ThERF1were studied by using he yeast one-hybrid and coexpression of effector and reporter vectors in leaves of tabacco using particle bombardment. The result showed that ThERF1can recognize GCC-box and DRE element specifically.Microarray analysis was performed on transgenic Arabidopsis line (PE12) and wild-type Arabidopsis under NaCl treatment. The result showed that461differentially expressed genes were obtained, and these genes may be the downstream genes regulated by ThERF1.