Bacterial diversity in honey sac during bee foraging on winter flowering flora and dominant Bacillus subtilis inhibits Hafnia alvei

Miao Wang ^1* Wenzheng Zhao ^2* Danyin Zhou ^2* Jian Huang ^2*

• ¹ College of Food Science and Technology, Yunnan Agricultural University, Kunming, Yunnan Province, China
• ² Yunnan Agricultural University, Kunming, China

The bacterial diversity of two bee species in the process of honey collection during the flowering season of three different floral sources in winter was studied. The common bacterium in all samples was Bacillus subtilis. Methods: In the present study, we collected nectar, honey sacs, and fresh honey during the winter flowering season of Agastache rugosa, Prunus cerasoides and Brassica rapa. The pure culture method was used to count and analyse the number of bacteria, identify them by 16S rRNA sequencing, compare similarities in NCBI, and determine the common dominant bacterial species B. subtilis in all samples by phylogenetic analysis and intersection analysis, do further bacteriostatic experiments. Results: The results showed that the most abundant quantity of bacterium could be found in honey sacs, other in nectar or fresh honey. At the same time, the highest abundance bacterial quantity could be found in honey sacs of A. cerana when collected on Brassica rapa, while the highest abundance bacterial quantity could be found in honey sacs of A. mellifera when collected on Prunus cerasoides and Agastache rugosa. A total of 33 bacterial species were isolated, with variations in their distribution across different sample types and sources. The inhibitory effect of 10 -1 -10 -5 on Hafnia alvei by B. subtilis was very significant. Conclusions: B. subtilis was identified in all sample sources, indicating the potential importance of B. subtilis as a probiotic in the bee gut for honey production, and B. subtilis could promote the disease resistance and health of honeybees in winter.