Fungal community analysis of two edible herbs: Citri reticulatae pericarpium and polygalae radix

Abstract

Citri Reticulatae Pericarpium(CRP) and Polygalae Radix (PR) are traditional Chinese medicinal herbs and dietary supplements, and they are commonly included in most prescriptions. Fungal contamination in CRP and PR has long been a concern for the public. Thus, in this study, the fungal diversity and abundance in CRP and PR were investigated via high-throughput sequencing technology. Analysis was conducted to determine the differences in dominant fungal microbiomes between mouldy and nonmouldy samples, and the correlation between the total number of fungi and fungal diversity in medicinal herbs at different altitudes and latitudes with other research was explored. Results show the fungal contamination of all 12 samples. At the phylum level, Ascomycota prevailed the most in CRP and PR with relative abundances of 56.96%–99.26% and 23.28%–76.06%, respectively. The dominant genera in CRP comprised Xeromyces (2.57%–53.21%), Aspergillus (0.18%–23.04%), Cystofilobasidium (0.032%–28.03) and Xerochrysium (0.31%–34.41%). The dominant genera in PR included Wallemia (0.27%–56.20%), Aspergillus (2.03%–48.06%), Xeromyces (0.20%–48.28%) and Xerochrysium (0.093%–43.95%). Two potential toxigenic fungi were detected: Alternaria alternata and Aspergillus versicolor. In addition, combined with the results of previous studies, the findings reveal the possible relation of diversity and abundance of fungal species to altitude and latitude: As the altitude and latitude decrease, the diversity and abundance of fungal species may increase. In conclusion, for the first time, this study focused on altitude and latitude as indicators and integrated multiple research findings to explore the correlation between the total amount and diversity of fungal species in the two edible herbs. Results reveal the fungal contamination of the surfaces of CRP and PR and provide a theoretical basis for the prevention and control of their fungal contamination.