Draft Genome Sequence of an Aspergillus Strain Isolated from a Honey Bee Pupa.

Insect-associated fungi play an important role in wild and agricultural communities. We present a draft genome sequence of an entomopathogenic strain from the fungal genus Aspergillus, isolated from a honey bee pupa.

A Bacterial Symbiont Protects Honey Bees from Fungal Disease.

Fungal pathogens, among other stressors, negatively impact the productivity and population size of honey bees, one of our most important pollinators (1, 2), in particular their brood (larvae and pupae) (3, 4). Understanding the factors that influence disease incidence and prevalence in brood may help us improve colony health and productivity. Here, we examined the capacity of a honey bee-associated bacterium, Bombella apis, to suppress the growth of fungal pathogens and ultimately protect bee brood from infection. Our results showed that strains of B. apis inhibit the growth of two insect fungal pathogens, Beauveria bassiana and Aspergillus flavus, in vitro. This phenotype was recapitulated in vivo; bee broods supplemented with B. apis were significantly less likely to be infected by A. flavus. Additionally, the presence of B. apis reduced sporulation of A. flavus in the few bees that were infected. Analyses of biosynthetic gene clusters across B. apis strains suggest antifungal candidates, including a type 1 polyketide, terpene, and aryl polyene. Secreted metabolites from B. apis alone were sufficient to suppress fungal growth, supporting the hypothesis that fungal inhibition is mediated by an antifungal metabolite. Together, these data suggest that B. apis can suppress fungal infections in bee brood via secretion of an antifungal metabolite. IMPORTANCE Fungi can play critical roles in host microbiomes (5-7), yet bacterial-fungal interactions are understudied. For insects, fungi are the leading cause of disease (5, 8). In particular, populations of the European honey bee (Apis mellifera), an agriculturally and economically critical species, have declined in part due to fungal pathogens. The presence and prevalence of fungal pathogens in honey bees have far-reaching consequences, endangering other species and threatening food security (1, 2, 9). Our research highlights how a bacterial symbiont protects bee brood from fungal infection. Further mechanistic work could lead to the development of new antifungal treatments.

Draft Genome Sequences of Four Saccharibacter sp. Strains Isolated from Native Bees.

The genus Saccharibacter is currently understudied, with only one described species, Saccharibacter floricola, isolated from a flower. In an effort to better understand the microbes that come in contact with native bee pollinators, we isolated and sequenced four additional strains of Saccharibacter from native bees in the genera Melissodes and Anthophora These genomes range in size from 2,104,494 to 2,316,791 bp (mean, 2,246,664 bp) and contain between 1,860 and 2,167 (mean, 2,060) protein-coding genes.

Draft Genome Sequence of a Bombella apis Strain Isolated from Honey Bees.

Bombella apis occupies a variety of distinct niches within a honey bee hive, including queen guts, royal jelly, and larval food. In an effort to better understand its evolution and identify signatures of honey bee association, we sequenced a strain isolated from hive honey stores. This genome is 2,086,308 bp long and contains 1,975 protein-coding genes.

Transitions and transmission: behavior and physiology as drivers of honey bee-associated microbial communities.

Microbial communities have considerable impacts on animal health. However, only in recent years have the host factors impacting microbiome composition been explored. An increasing wealth of microbiome data in combination with decades of research on behavior, physiology, and development have resulted in the European honey bee (Apis mellifera) as a burgeoning model system for studying the influence of host behavior on the microbiota. Honey bees are eusocial insects which exhibit striking behavioral and physiological differences between castes and life stages. These include changes in social contact, environmental exposure, diet, and physiology: all factors which can affect microbial composition and function. The honey bee system offers an opportunity to tease apart the interactive effects of all these factors on microbiota composition, abundance, and diversity.