Characterization And Functional Validation Of Ascorbate Peroxidase Gene From Reaumuria Trigyna

Reaumuria.trigyna (Reaumuria Linn genus, family Tamaricaceae) is an endemic plant in China. Because it can tolerate the stress imposed by desert and saline soil, R.trigyna plays an important role in reversing soil salinization and preventing desertification. The main role of ascorbate peroxidas(APX)is to utilize ascorbate as an unique electron donor and it can catalyze H2O2 conversion to H2O for clearing additional H2O2. The role of the R.triyna in the tolerability and growth can be better understood by studying the APX gene.In this study, we screened members of APX genes from transcription library of R. trigyna and obtained an APX gene named as APX1.In addtion,we analyzed the Characterization and functional validation of APX1. The main results are as follows:1.The open reading frame and amino acid sequence of the RtAPX1 was obtaned by open reading frame(ORF) Finder of NCBI.Bioinformatic analysis revealed that the ORF length of the RtAPXl is 861bp and it encodes a 286-amino acid protein (31.29 kDa, isoelectric point=6.61). Protscale and SOPMA was used, and the results showed that the RtAPX1 encodes a hydropathy protein and its major secondary structure includes alpha helix and random coil. Mega6.0 was utilized to build the Phylogenetic tree.The result indicated that APX1 protein is closely related to the APX protein of salicornia and Tamarix hispida.2. Real-time PCR analysis revealed that the expression of the RtAPXl was significantly increased under 100mM,200 mM,400 mM NaCl stimulation and drought, coldness stress, and achieved highest expression level after 12 hours. A pUC18-RtAPX1 subcellular localization vehicle was constructed and the result showed that the APX1 protein existed in cytosolic, thus it’s a type of cytosolic APX (cAPX).3.A pPICZ α - RtAPXl recombinant vehicle was constructed and After transfered into yeast. The phenotype analysis of the engineered yeast indicated that the RtAPX1 overexpression improved yeast’s tolerance against NaCl, drought, low temperature and UV light.The present study proved the RtAPXl, as one of the key H2O2 clearance enzyme genes, played an important role in R.trigyna’s tolerability. Our result verified the RtAPX1’s function. Thus, it could support further studities regarding of the mechanisim of the APX and the improvement of the plant’s tolerability...