Study On The Function Of Thioredoxin Peroxidase Gene In Beet M14 Strain

Sugar beet M14 is the monosomic addition line by adding the No. 9 chromosome of B. corolliflora Zoss to the chromosomes of B.vulgaris L. It is identified that M14 has some excellent characteristics, such as salt resistance and apomixis, possibly because the import of the No. 9 chromosome of B. corolliflora Zoss makes it obtain some good genes from the wild species. So M14 is a good material which can be used to explore the quality genes.Thioredoxin peroxidase(Tpx) is a member of the family peroxidase Peroxiredoxin(Prx). In recent years, the researchers have found that plant Tpx gene has widely participated in the plant abiotic stress response reaction, suggesting that Tpx has potential application value in the study of crop improvement and the mechanism of resistance of plants.Based on the previous research in our lab, this experiment obtained the overall length of Bv M14-Tpx c DNA of M14 line by RACE technique, which included a total of 1 044 bp and contained the 489 bp ORF and coded 162 aa. Besides, sequence analysis showed that its amino acid sequence contained two cysteine residues; the protein contained three protein kinase C phosphorylation sites, one acetoxylation site and four casein kinase phosphorylation sites. Moreover, Real-time PCR analysis results showed that Bv M14-Tpx gene was widely expressed in the roots, stems, leaves and flowers of M14 line, and its expression quantity is the highest in root.Besides, the E.coli expression system of Bv M14-Tpx gene was built. Compared to the blank carrier strains, the growth curve result showed that the transferring Bv M14-Tpx gene E. coli BL21(DE3) bacteria entered growing period 1h earlier than the control strains under the stress of H2O2, suggesting Bv M14-Tpx genes can ease the inhibition of H2O2 on the growth of E. coli.The Bv M14-Tpx gene eukaryotic expression system was built. Compared to blank carrier strains, the growth conditions of Saccharomyces cerevisiae showed that genetically modified yeast growed better than control under H2O2 and Na Cl stresses, suggesting that Bv M14-Tpx can improve the salt tolerance ability of genetically modified yeast.In addition, the Bv M14-Tpx gene plant expression vector was built which was transferred into the Arabidopsis thaliana mutant strains to recover. Compared to wild-type Arabidopsis WT, real-time PCR result showed that the expression quantity of Bv M14-Tpx gene in transgenic recovery plants was more than that of Tpx in WT under H2O2 and Na Cl stressed, suggesting Bv M14-Tpx gene expressed successfully in Arabidopsis thaliana.The seedlings growth and root length of wild-type Arabidopsis WT, Arabidopsis thaliana Tpx mutant and reverse mutant were compared. The result showed that the growth and root length of reverse mutant were almost consistent with those of the WT, yet better than those of Arabidopsis Tpx mutations. The results of oxygen free radical content showed that the oxygen free radicals in the transgenic arabidopsis recovery plants were bacially the same with that in wild-type arabidopsis WT yet was lower than that of Arabidopsis thaliana Tpx mutant. At the same time, the measurement result of the K+ content had no significant change. In addition, the measurement results of Na+ content showed that the Na+ content in transgenic arabidopsis recovery plants was basically consistent with that in WT and both were lower than that of Arabidopsis tpx mutations. The above results confirmed that the recovery of Bv M14-Tpx gene in Arabidopsis thaliana tpx mutant can restore the resistance ability to oxidation and high salt stress of Arabidopsis thaliana.Based on research the function of Bv M14-Tpx gene, the experiment provides important value to reveal Tpx gene resistance mechanisms.