Copper/Zinc Supperoxide Dismutase Gene Cloning Of Gynura Bicolor D.C And Its Expression After Various Postharvest Treatments

Gynura bicolor D.C(G.bicolor)is rich in microelements,anthocyanins,amino acids,essential oil and flavonoid,and also has high SOD activity,therefore it has high quality value from both vegetable and medicinal point of view.Since the living organism with high metabolic activity after harvest is prone to losing nutrients and appearance after harvest,proper post-harvest treatments are in need for G.bicolor production.Most studies focused on the physiological and biochemical aspects of post-harvest treatments at present,while little gene expression was reported.This experiment herein explored the cloning and characterization of Cu/Zn-SOD gene,and the bioinformatics analysis and expression of Cu/Zn-SOD from G bicolor under different postharvest treatments were also investigated,which will be helpful in providing evidence for future research.The main results are as follows:1.The total RNA,which was isolated from the G.bicolor leaves using a modified CTAB method,is obtained.The full-length sequence of cDNA consists of 924 bp nucleotides,and it contains an open reading frame(ORF)of 681 bp at position 104-784 bp,encoding a deduced protein of 227 amino acid residues.The alignment analysis revealed that G.bicolor Cu/Zn-SOD shared high homology with many other Cu/Zn-SODs,such as Helianthus annuus Cu/Zn-SOD(CAH06454.1),Mikania micrantha Cu/Zn-SOD(ACZ51444.1)and Solidago canadensis var.scabra Cu/Zn-SOD(004996.3).The primary structure analysis deduced that the protein could be a hydrophilia,non-secretory proteinin and in cytoplasmic matrix.On the whole structure,random coil and extended strand is the main structural element,a-helix and ?-turn are distributed in the protein.According to the prediction method of homology modeling,the potential tertiary structure of the Cu/Zn-SOD from G.bicolor was established using the SWISS-MODEL workspace,which had directly impact on the subsequent molecular biology research.2.G.bicolor was treated with 1-MCP and ethylene respectively.The effect of 1-MCP treatment was less respiratory intensity,higher L*value,higher the expression level of Cu/Zn-SOD gene and activity of superoxide dismutase(SOD)and peroxidase(POD),slower generating rate of super oxygen anion and H2O2,and maintaining the quality of storage.While the opposite effect of ethylene.3.The results showed that the four treatments caused the upregulation of Cu/Zn-SOD gene with different degree,and 1-MCP treatment was the most obvious.Different expression patterns of treatments result from different regulatory mechanism.The influence of the 1-MCP,controlled atmosphere,and hypobaric treatments on the expression of Cu/Zn-SOD gene was time-controlled.In this study,we also found that a low temperature could induce expression of Cu/Zn-SOD gene.