Preparation And Efficacy Evaluation Of Specific Egg Yolk Immunoglobulin (IgY) Against Brown Rot Cherry Fungi

Brown rot is one of the most serious and common diseases of cherry and other stone fruits at present.The morphological characteristics and culture characters of Monilinia fructicola caused brown rot is of great intraspecific variations and plasticity,so it is diffcult to identify the pathogen accurately by traditional cultivation method.At the same time,the control of the disease using chemical agents has many disadvantages.There fore, it is an urgent affair to seek a safe, economic and efficient technology used for the prevention and control of cherry brown rot.In this study,we used a molecular method based on DGGE coupled with sequence analy-sis of 18S rRNA gene to assess fungal diversity on cherry of brown rot. To achieve this, we extracted total genomic DNA and used fungal specific primers (NS1 and GCFung) to obtain fungal sequences. PCR-DGGE analysis obtained 5 operational taxonomic units (OTU) from different areas of the studied brown rot of cherry.They were Ciboria batschiana, Monilinia-laxa,Monilinia fructicola,Sclerotinia sclerotiorum,Sclerotinia trifoliorum,respectively.Monil-inia fructicola were preponderant and shared.Subsequently, egg yolk immunoglobulin(IgY) against M. fructicola was produced.The cell wall and whole cell of M. fructicola were respectively used as antigens to immunize laying hens,and thus obtaining the specific IgY. The activity of IgY was detected by indirect enzyme-linked immunosorbent assay (ELISA). The results demonstrated that the activity of water soluble fraction(WSF)of IgY specific to whole cell and IgY specific to cell wall showed a significant difference compared with the control group.And the antibody activity in whole cell group was much higher when the concentration of protein was 4 mg/mL than that of 3mg/mL. Moreover,when the cell wall was used as antigen,the antibody activity was much greater than that of another group,in which the whole cell was used as antigen.The bacteriostatic activity was dose-dependent when the concentration of the IgY was from 0 mg/mL to 50 mg/mL, and the growth of M. fructicola was evidently inhibited by specific IgY at the concentration of 25 mg/mL. The control effects of specific IgY was determined in cherry of storage period.Fruits were wounded and artificially applied M. fructicola following the application of 25 mg/mL specific IgY,and the results indicated the brown rot of cherry was defered 12 h.And when fruits were wounded and applied 25 mg/mL specific IgY following the application of M. fructicola, the brown rot of cherry was deferred 24 h. The activity of PPO in cherry after inoculation with IgY at a high level throughout the experiment, but the activity of POD was not stimulated.In summary,it can be said that fungi on cherry of brown rot definited in the study can provide theory basis of disease prevention and postharvest storage.and the specific IgY prepared in this study can provide a noval approach to preventing and treating the infection of M. fructicola.