Diversity, antibacterial and antioxidant activities of fungi associated with .

Insect-associated fungi are a treasure trove of natural active compounds. Nevertheless, the diversity and biological activities of fungi associated with have not been studied in depth. Here, we investigated fungal diversity in the gut and honeycomb using a combination of culture-dependent and -independent methods. A total of 652 fungal operational taxonomic units belonging to five phyla and 334 genera were detected in the samples. Significant differences were found in the fungal communities of the honeybee gut and honeycomb-the genera , , and were dominant in the gut, whereas , , and were dominant in honeycomb. A total of 28 fungal strains were isolated from honeybee gut, head, and honeycomb, belonging to two phyla, four classes, and 10 genera. Most of these isolates were identified as , , and spp. The antibacterial and antioxidant activities of crude extracts of their fermentation broths were investigated. Extract from ZFCZ33 exhibited the best antibacterial activities against , , , and pv. with the disc diameter of inhibition zone diameter (IZD) of 24.33, 15.33, 17.00, and 25.33 mm, respectively. Extract from ZFCZ03 had a free radical scavenging rate of 89.71% in assay with 2,2-diphenyl-1-picrylhydrazyl, and that from strain ZFT07 had a free radical scavenging rate of 97.13% in assay with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid). Our results preliminarily elucidate the fungal diversity of gut and honeycomb and indicate that honeybee-associated fungi have antibacterial and antioxidant activities. This study provides a basis for further development and use of honeybee-associated fungi.