Control Of The Compound Strain On Anthracnose Of Postharvest Mango Fruit And The Applicational Study

The anthracnose caused by Colletotrichum gloeosporioides,is the main disease of postharvest mango fruits,which is the most important factor causing the decay of mango fruit during storage and preservation.In this paper,three antagonistic microorganisms(Y-1,T18 and TE-7)isolated from our laboratory previously were used as materials.The preservation effects of single treatment with Y-1,T18 and TE-7 and compound treatments on mango fruits were studied.In addition,the natural substances as synergistic agent of compound strains were screened,and a compound biological preservatives with high potency and stability was identified.Meanwhile,the lyophilization condition and application effects on several tropical fruits were studied.The main results are as follows:(1)To observe the effects of three antagonistic strains on the spore germination and mycelial growth of anthracnose pathogen by microscopy.It was found that the mix ture of Y-1 and TE-7 caused the spore germination rate of anthrax to be as low as 17.6%and the bacteriostatic bandwidth to be 15 mm.In vivo experiments showed that the mixture treatment of Y-1 and TE-7 could significantly enhance the enzyme activities related with anti-disease,including phenylalanine ammonia lyase(PAL),peroxidase(POD),and?-1,3-glucanase(GLU),and inhibit the increase in disease index and delay the ripening and senescence of mango fruits.(2)To screen of natural substances as synergistic agent.In vitro experiments and the monitoring on growth curve of TE Y-1 and TI-7,showed that tea polyphenols,riboflavin and mango leaf ethanol extract(ML)effectively inhibited the growth of pathogenic mycelium,and promoted the growth of Y-1 and TE-7.The combination of natural substances and C-Y-TE showed that tea polyphenols and ML-containing tea polyphenols could further enhance the inhibition effect of C-Y-TE on the mycelial growth of anthrax in vitro.(3)The effects of natural substances as synergistic agent on storage quality and activities of anti-disease enzymes of mango fruit were studied.The results showed that combination tea polyphenols with C-Y-TE could obviously increase the activities of PAL,POD,GLU and CHI,and significantly delay the change progress of fruit firmness,soluble solids(TSS),titratable acid(TA)and vitamin C(Vc).So,the synergistic effects of tea polyphenols was most obviously and could be used as synergistic agent.(4)The protective agents of compound strains were studied.Through the method of flat coating and microscope observation,it was found that the skimmed milk powder with 0.08 g/mL could effectively alleviate the damage of cell membrane of Y-1 caused by vacuum freeze drying,and deduce the cells expansion and elongation of TE-7.Finally,a new kind of compound biological preservatives(C-Y-TE+tea polyphenols+skimmed milk powder)was obtained.(5)To study the application effect of compound biological fresh-keeping agent,the'Tainong' mango,'Risheng' papaya and 'Daye' wax-apple fruits were used.The results showed that the compound biological agent could significantly not only reduce the disease index,maintain the appearance qualities,but also delay ripening and senescence of mango,papaya,and wax-apple fruits.In short,the compound biological agent obtained by us has great application potential in storage and transportation of fruits and vegetables in future.