Identification And Analysis Of Mz₂NHX₁ Gene Transformed Into Arabidopsis Thaliana

In this study,received 30 strains of T₁ generation of resistance to the kanamycin Mz₂NHX₁ gene in arabidopsis.Through PCR and RT-PCR detection,can be amplified to obtain about 1635 kb bands,consistent with the size of the target gene fragment.The T₁ generation seeds were screened for kanamycin resistance,of which 9 strains were separated by 3:1,PCR and RT-PCR were detected and the results were positive.Each strain was harvested separately,recorded as T₂ generation seed.The T₂ generation seeds continued to be screened by kanamycin,and 4 strains were no longer isolated.The results showed that the Arabidopsis homozygous strain carrying Mz₂NHX₁ gene was successfully obtained.GUS staining analysis showed that Mz₂NHX₁ gene was expressed in leaves and roots of Arabidopsis thaliana.With the increase of salt stress and drought stress,the activity of SOD in wild type and transgenic Arabidopsis increased firstly and then decreased,SOD activity increased to maximum at 100 mmol L^-1 Na Cl and 10% PEG treatment,the decrease of SOD activity in wild type Arabidopsis was greater than that in transgenic plants under severe stress;The changes of POD activity in wild type and transgenic Arabidopsis were not obvious under mild stress,under the treatment of 300mmol·L^-1 Na Cl and30% PEG-6000,the POD activity of the transgenic plants was 1.55 times and 2.16 times higher than that of the wild type;Both MDA content and electrical conductivity of wild type and transgenic Arabidopsis were increased with the increase of stress,and the increase rate of wild type Arabidopsis was higher than that of transgenic type;The proline content of wild type and transgenic Arabidopsis showed a rising trend;Chlorophyll and carotenoid content increased first and then decreased;The content of soluble protein in transgenic Arabidopsis first increased and then decreased,while the wild type showed a downward trend;The soluble sugar content of wild type and transgenic Arabidopsis increased with the increase of salt concentration,and increased first and then decreased under drought stress,soluble protein and soluble sugar content of transgenic Arabidopsis were higher than that of wild type.The physiological indexes of transgenic plants were better than that of wild type under salt stress and drought stress.The results showed that the overexpression of Mz₂NHX₁ gene could make transgenic Arabidopsis more adaptable to stress and improve the salttolerance and drought tolerance of plants.The expression of Mz₂NHX₁ gene in transgenic Arabidopsis thaliana under Na Cl and PEG-6000 stress at different concentrations and different time was analyzed by real-time fluorescence quantitative PCR.The results showed that salt stress and drought stress could increase the expression of Mz₂NHX₁ gene in a certain range,which increased the transport activity of the protein.The excessive Na+ transport to the vacuole,reduce the toxicity of Na+ to the cell,and reduce the cell water potential,improve the water absorption capacity of the cell,it is proved that the Mz₂NHX₁ gene is closely related to the salt tolerance and drought tolerance of plants.