Mycotoxin Production and the Relationship between Microbial Diversity and Mycotoxins in Pyrus bretschneideri Rehd cv. Huangguan Pear

Mycotoxins are generated by a series of fungal pathogens in postharvest fruit, resulting in serious health threat to consumers and great economic loss to the fruit storage industry. The microbial differences between rotten and healthy fruit during storage and their relationship with mycotoxin production have not been fully studied. In this study, differences in microbial diversity between rotten and healthy fruit after 30 days of storage at ambient temperature were investigated using high-throughput sequencing technology in ‘Huangguan’ pear (Pyrus bretschneideri Rehd cv. Huangguan) harvested from five different producing regions of Hebei province, China. The bacterial genus Gluconobacter was much more abundant in rotten fruit (76.24%) than that in healthy fruit (32.36%). In addition, Komagataeibacter and Acetobacter were also relatively higher in abundance in rotten fruit. In contrast, bacterial genera Pantoea, Alistipes, Muribaculaceae, Lactobacillus, and Ruminococcaceae_UCG were found to be more abundant in healthy fruit. Fungal genera including Botryosphaeria, Colletotrichum, Valsa, Alternaria, Rosellinia, Fusarium, and Trichothecium were found to be abundant in rotten fruit. The results of principal coordinate analysis (PCoA) showed that there were significant differences in the microbial diversity of different regions. PAT (patulin) was detected in all rotten fruit samples, while tenuazonic acid (TeA), alternariol (AOH), and alternariolmonomethyl ether (AME) were only detected in samples collected from one region (Weixian). Canonical correlation analysis (CCA) and Pearson correlation analysis showed that the abundance of Alistipes and Pantoea were negatively correlated with the contents of PAT, suggesting that bacterial genera Alistipes and Pantoea have potential in reducing mycotoxin production in ‘Huangguan’ pear.