预冷方式对红玛瑙樱桃果实冷藏期间真菌多样性的影响

Pre-cooling Methods Affect the Diversity of Fungal Communities on Red Agate Cherry Fruit during Cold Storage

不同的采后预冷方式会影响樱桃果实的冷藏腐烂率,这主要源于果实表面真菌组的发展变化。以高通量测序法测定真菌组内转录间隔区序列,分析经不同预冷处理后的红玛瑙樱桃在冷藏0、15、30 d时表面真菌的群落构成和多样性,并重点分析优势菌的变化趋势。结果表明:相对于风冷,冰水预冷和臭氧化冰水预冷降低了红玛瑙樱桃冷藏初始和冷藏期内真菌组的丰富度和Alpha多样性。优势菌群分析表明,各组樱桃初始优势菌均包括出芽短梗霉菌(Aureobasidium pullulans)、格孢腔菌目(OTU 1)、链格孢属(OTU 4)和Davidiellaceae科(OTU 3),但冰水和臭氧化冰水预冷降低了初始病原菌比例,提高了生防菌(出芽短梗霉菌)的比例;冷藏期间,各组优势菌相发生变化。在贮藏30 d时,风冷样品Davidiellaceae科(OTU 3)是最主要的腐败菌;冰水预冷样品中生防菌出芽短梗霉菌占据绝对优势,格孢腔目(OTU 1)、链格孢属(OTU 4)、Davidiellaceae科(OTU 3)和腊叶芽枝霉比例分别上升到16.28%、8.23%、8.40%和8.96%,它们可能引起樱桃腐败;臭氧化冰水预冷樱桃表面格孢腔菌目(OTU 1)占据绝对优势,链格孢属(OTU 4)占比14.26%。研究结果揭示了预冷方式对红玛瑙樱桃采后冷藏期真菌菌相的影响,也为预冷方式的选择以及其他抗菌技术的应用提供了基础数据。

Different post-harvest pre-cooling methods can influence the incidence of decay in cherry fruits,mainly due to the development of fungal community on the fruit surface.The composition and diversity of fungal community on the surface of Red Agate cherry fruit subjected to different pre-cooling treatments were analyzed during subsequent cold storage for up to 30 days,with focus on the changing trend of the dominant microbes.The internal transcribed spacer(ITS)sequence was determined by high throughput sequencing.The results showed that compared with cold air cooling,treatment with unozonated or ozonated ice water reduced the abundance and alpha diversity of the fungal microbiome during the storage period.The initial dominant fungal composition was similar in the three pre-cooling groups,including Aureobasidium pullulans,Pleosporales(one operational taxonomic unit(OTU)),Alternaria sp.(4 OTUs)and Davidiellaceae(3 OTUs).Both ice water treatments reduced the proportion of initial pathogenic fungi and increased the proportion of biocontrol fungi(Aureobasidium pullulans).During storage,the dominant fungi in each group developed.On the 30 th day,Davidiellaceae(3 OTUs)became the dominant fungus in cold air treated samples.In unozonated ice water treated samples,Aureobasidium pullulans developed into the dominant fungus;however,the proportion of Pleosporales(1 OTU),Alternaria sp.(4 OTUs)and Davidiellaceae(3 OTUs)and Davidiella tassiana increased to 16.28%,8.23%,8.40%and 8.96%,respectively,which may cause spoilage on the surface of cherry fruit.Pleosporales was the dominant fungus in the ozonated ice water treatment group,and Alternaria(4 OTUs)accounted for 14.26%of the total fungi.These results revealed the effects of pre-cooling methods on the fugal community of Red Agate cherry fruit during post-harvest cold storage,which will provide fundamental data for the choice of pre-cooling methods and the application of other anti-fungal technologies.