Investigation of fungal contamination in medicinal and edible Lycii Fructus through DNA metabarcoding.

Aims: Lycii Fructus (LF) is considered as a 'superfood' due to its health benefits and delicious tastes, which has gained popularity worldwide. However, LF is also a proper host for fungal growth due to its abundant nutrients. Fungal contamination seriously affects the quality and safety of LF and poses threats to consumer health.

Methods And Results: In this study, a total of 15 LF samples were collected from five provinces in China, and were divided into five groups based on the collection areas. Fungal contamination in LF was investigated by targeting the internal transcribed spacer 2 region using Illumina Miseq PE300 platform, and the differences of fungal community in groups based on collection areas were compared. Results showed that the fungal contamination was detected in all the 15 LF samples. Ascomycota, Dothideomycetes, Pleosporales and Pleosporaceae were dominant at the phylum, class, order and family levels, respectively. At the genus level, Alternaria, Cladosporium and Fusarium were the three dominant genera. In all, 24 fungal species were identified. Among which, two species, namely Penicillium oxalicum and Trichothecium roseum, were potentially toxigenic.

Conclusions: All 15 LF samples were detected with fungal contamination. The differences of fungal community in LF samples collected from different areas were observed. DNA metabarcoding was demonstrated as an efficient method to monitor the fungal contamination in LF.

Significance And Impact Of The Study: This work comprehensively reveals the fungal diversity and composition in LF and provides early warning for potential mycotoxin contamination.