Identification And Biocontrol Of Latent Pathogenic Fungi In Blueberry Fruits

Postharvest decay of fruits and vegetables by fungal disease leads to economic losses and damages people's healthy by produced toxin.Blueberry is a burgeoning fruit which has highly nutritional and economic value.Fruit decay in blueberries is usually caused by fungi which decreased production,shortened shelf life and limited development of industry.Our studies aim to research fungal species and harm of blueberry at postharvest.Apply the antagonist yeast Hanseniaspora uvarum isolated from blueberry fruit to control blueberry decay before postharvest.The results were shown as below:1.Using the tissue isolation method,nine latent pathogenic strains were isolated.Morphology and molecular biology were used to identify the 9 fungal strains namely Alternaria alternata,Alternaria tenuissima,Cladosporium sp.,Botrytis cinerea,Aspergillus niger,Penicillium Pinophilum,Phoma sp.,Chatetomium sp.,Fusarium sp.These fungi can cause blueberry decay.In addition,Alternaria alternata and Botrytis cinerea were the main latent infection fungi in blueberry fruits.2.The occurrence of latent infection of pathogenic fungi in blueberry fruits of 8 cultivars from Liaoning Province was investigated.The results showed that the latent infection of fungi was commonly found in the healthy blueberry fruits and there existed significantly difference in the latent infection rates among different cultivars.The rate of latent infection in M7 was the highest as compared to other cultivars such as Brigitta,O'Neal and Southgood.3.Hanseniaspora uvarum isolated from blueberry fruit showed a strong antagonistic effect on Penicillium Pinophilum,Botrytis cinerea,Chatetomium sp.,Aspergillus niger,Alternaria alternate,Fusarium sp.,the inhibition rate were : 89.34%,87.81%,77.12%,76.45%,71.08% and 59.88%.4.The blueberry natural decay incidence and decay index were 5.1% and 1.7% lower than the control,37.50% and 19.72% respectively.H.uvarum combined with salicylic acid was the best treatment amongst other pre-harvest applications of biological agents such as H.uvarum and H.uvarum combined with chitosan oligosaccharide.H.uvarum can significantly inhibit Botrytis cinerea.The induction of resistance to pathogenic fungi through the treatment with biological agents is associated with significant enhancement of the activities of some defense-related enzymes,comprising superoxide dismutase,peroxidase and phenylalanine ammonia-lyase.