Diversity analysis of microorganisms on the surface of four summer fruit varieties in Baotou, Inner Mongolia, China

Improper storage of post-harvest fruits leads to significant losses, especially due to microbial-induced decay. Understanding the naturally occurring microbial communities on fruit surfaces and their functions is the first step in the development of new strategies for controlling post-harvest fruit decay. These new strategies could generate significant economic value by improving fruit preservation and extending the shelf-life of fruit. In the present study, 16S rRNA and ITS high-throughput sequencing technologies were used to analyze the diversity and composition of microorganisms on the surfaces of four different fruit varieties: three plum varieties and one apple variety, all from the same orchard in Donghe District, Baotou City, China. The results displayed no notable difference in bacterial diversity on the surfaces of the four varieties of fruits (P > 0.05), but there were significant differences in fungal diversity (P < 0.05). The most abundant bacterial phyla detected on the fruit surfaces were Proteobacteria, Bacteroidota, and Firmicutes; the most abundant fungal phyla were Ascomycota, Basidiomycota, and Mortierellomycota. Though microbial compositions on the fruit surfaces differed between the fruits, the surface microbial community structure of the three plum varieties exhibited higher similarity, indicating that fruit type is a key factor influencing the composition of surface microorganisms. There were also differences in the epidermal microbial community composition between the fruits involved in this study and fruits of the same species reported from other regions, suggesting that geographical factors also play a critical role in microbial composition. The correlation analysis revealed significant associations between the microorganisms with the highest abundance on the surface of the fruits, suggesting the existence of symbiotic and mutualistic relationships between these microorganisms, but the specific mechanisms behind these relationships need to be further explored. This study provides a basis for the establishment of post-harvest fruit preservation strategies.