The Expression Analysis Of Gene LOX-3 In Peach(Prunus Persica L.)

Fruits of peach varieties 'Ruipan 4', 'Jianayan' and 'Huayu' as materials, this research was mainly studied that PpLOX-3' gene of peach (Prunus persica L.) lipoxygenase (lipoxygenase, LOX) was expressed in prokaryotic cell, which located in onion's epidermic cells, and PpLOX-3' gene expression in different treatments and related index analysis about ripe softening, the PpLOX-3' expressed characters and function of PpLOX-3' during the fruit ripe softening and ethylene signal transduction were studied, main results as followed:1.The complete ORF sequence of PpLox-3 has been introduced into E. coli cells(BL21) by using the PET28a expression vector. SDS-PAGE showed that recombinant PpLox-3 (125kD) was expressed in pET-LOX-3 cells induced by IPTG, maximal expression was noted after 0.6mmol/L IPTG-mediated induction under 20℃, while under 37℃, the maximal expression was induced by 1.0mmol/L IPTG. Because the vector itself coding a protein of 20kD , the protien of 105kD we obtained was in accordance with the predicted molecular weight of PpLox-3, these have proved that PpLox-3 can coding a protein of 105kD.2.Bioinformatics analysis showed that, PpLox-3 coded a protein of 105870.2 D , the molecular formula was C₄₇₈₀H₇₄₄₃N₁₂₇₁O₁₃₈₅S₃₁,and the PI was 6.37, and it was a soluble and labile protein. In PpLox-3's secondary structure, the helix took up 30.76%, inear chain 10.61%, while circline took up 58.63%. it was proved to be located to cytomembrane. We constructed a plant expression vector in which Green fluorescent protein function as a report gene, then transformed the fusion expression vector into the epidermic cells of onion. The results showed that PpLox-3 was located into the cytomembrane of onion'epidermic cells , it was a membranin.3.Treat the harvested peach of cv. Jianayan and cv. Huayu with different treatments. We found that both the mechanical damage and MeJA treatment could advance the arise of the release peak of ethylene, and would not enhance the ethylene express production, these two treatments could also enhance the enzymatic activity of ACO and PG and induced the expression of PpLox-3 at the same time. Instead, SA treatment could obviously delay the release peak of ethene, and do not enhance ACO and PG'activity ,but have inhibited PpLox-3'expression .The above results indicated that, the molecular weight of PpLox-3 was 105kD, and it was a soluble and labile protein which was located in cytomembrane and other biomembrane, was a kind of membranin. PpLox-3 was showed to play an important role in the maturation of peach, and was related with fruit's maturation.