Analysis Of Salt Tolerance In Transgenic Tobacco With PsATX Gene And PsSOD Gene

Copper (Cu) chaperones constitute a family of small Cu+ binding proteins required for Cu homeostasis in cytoplasm. The ATX1 family of Cu chaperones was involved in antioxidative activity.The partial sequence of a PsATX-1 gene was obtained from a random clone in polygonum sibicum SSH library and PsATX-1 was cloned by using rapid amplification of cDNA end (RACE) technology. The gene accession nucleotidesequence number in GenBank was EU620702.Sequence analysis indicated that the protein, such as most of the plant ATX1,including anamino-terminal (N-terminal) signature sequence of "MXCXXC",which possess to the heavy metal binding site,but in lack of carboxy-terminal domain (CTD)signature sequence. Quantitative analysis of PsATX-1 gene expression was carried by using Real-time PCR method.The result showed that PsATX-1 gene express in leaves,stem and underground stem.PsATX-1 was influence by 3% NaHCO3, the different express modes can be find in leaves,stem and underground stem.In aerobic organisms,protection against oxidative damage involves the combined action of highly specialized antioxidant enzymes,such as Cu/Zn superoxide dismutase.In this work,a cDNA clone encoding a Cu/Zn superoxide dismutase gene, named PsSOD-1,has been identified from Polygonum sibiricum Laxm by the rapid amplification of cDNA ends method(RACE).The Gene Accession nucleotide sequence Number in GenBank was GQ472846.Sequence analysis indicated that the protein, such as most of the plant SOD,including the conserve domain named'Cu-Zn_Superoxide_Dismutase'from the second amino acids to the one hundred thirty-sixth amino acids.Expression analysis by real-time quantitative PCR revealed that PsSOD-1 gene expression in leaves,stem and underground stem.PsSOD-1 gene expression can be induced by 3% NaHCO3,the different expressing of PsSOD-1 mRNA levels showed that the gene different express modes in leaves,stem and underground stem under the Salt Stress.In salt-stress condition, the content of superoxide dismutase(SOD) and proline of transgenic plants were generally higher than those of the control, while relative ROS and MDA of transgenic plants were generally lower than those of the control.These results showed that the co-transformed PsATX-1 and PsSOD-1 gene contributed to improved salt resistance of the transgenic tobaccos.