Effect of Cold Plasma on Microbial Community of ‘Golden Delicious’ Apples in Cold Storage

The effect of cold plasma on the composition and diversity of apple surface fungi and endophytes in cold storage was analyzed by high-throughput sequencing. Microbial co-occurrence networks were constructed. The results showed that cold plasma significantly inhibited the elevation of the α diversity of apple surface fungal communities and affected their composition during cold storage, but there were no significant effects of cold plasma on apple endophytic communities. The predominant fungi on the apple surface were unidentified (52.76%), Penicillium (14.70%), Aspergillus (13.80%) and Acremonium (8.33%). Cold plasma reduced the relative abundance of potentially harmful postharvest fungi on the surface of apples such as Penicillium, Aspergillus and Acremonium. The dominant endophytic bacteria of apples were unidentified (80.78%), Staphylococcus (4.23%) and Bacillus (3.13%). Cold plasma decreased the relative abundance of endophytic Staphylococcus, Bacillus and Corynebacterium. The dominant endophytic fungi of apples were unidentified (30.69%), Rhizopus (18.15%), Lysurus (6.56%), Aspergillus (4.38%) and Cutaneotrichosporon (3.26%). Cold plasma caused a significant decrease in the relative abundance of Zygosaccharomyces, Mortierella and Penicillium. The symbiotic networks of surface fungi and endophytic bacteria of ‘Golden Delicious’ apples were more complex, with more key nodes and complex correlations between nodes. Cold plasma could affect the co-occurrence networks of surface fungi and endophytic bacteria, simplifying their structures. But the co-occurrence network of endophytic fungi was simple in structure with less connectivity between nodes.