蜜蜂与熊蜂肠道真菌群落组成与代谢潜力解析

Gut fungal community composition and metabolic potential in honeybees and bumblebees

摘要:

蜜蜂与熊蜂作为重要的农业传粉昆虫，其肠道微生物在宿主营养代谢、免疫调节与环境适应中发挥关键作用。尽管肠道细菌群落已被广泛研究，肠道真菌的组成特征与生态功能尚缺乏系统性认知。为了系统揭示传粉昆虫肠道真菌的群落结构与潜在功能，本研究基于文献公开数据的内部转录间隔区(internal transcribed spacer, ITS)扩增子测序结果，系统解析了中华蜜蜂(Apis cerana)、意大利蜜蜂(Apis mellifera)、美洲熊蜂(Bombus impatiens)和黑尾熊蜂(Bombus vosnesenskii)肠道真菌群落的结构特征；同时结合从采集自北京市百花山国家级自然保护区的蜜蜂(Apis spp.)和熊蜂(Bombus spp.)肠道样本中分离获得的25株可培养真菌，开展了全基因组分析。结果表明，子囊菌门(Ascomycota)为优势类群，不同宿主之间真菌多样性与群落组成存在显著差异。系统发育分析表明，分离菌株在种属水平上具有较高的一致性，并表现出多样的基因组结构。功能注释显示，肠道真菌广泛参与碳水化合物代谢、细胞结构维持与信号调控，梅奇酵母属(Metschnikowia)菌株在糖苷水解酶(glycoside hydrolases, GH)与糖基转移酶(glycosyl transferases, GT)等CAZymes家族中表现出高度富集。此外，部分菌株具备非核糖体肽(nonribosomal peptide synthetase, NRPS)与β-内酰胺类代谢产物的合成能力，可能在菌群竞争和宿主互作中发挥生态调节功能。本研究揭示了蜂类肠道真菌群落的多样性与功能潜力，丰富了对昆虫微生物组结构与生态作用的理解，为传粉昆虫健康维持与微生态干预提供了理论基础。

Abstract:

Honeybees and bumblebees are key agricultural pollinators, whose gut microbiota play critical roles in host nutrient metabolism, immune regulation, and environmental adaptation. While gut bacterial communities have been extensively studied, the composition and ecological functions of gut fungi remain poorly understood. This study aims to fill this knowledge gap by systematically characterizing the diversity, phylogeny, and functional potential of pollinator gut fungi. In this study, we analyzed the gut fungal community structures of four pollinator species—Apis cerana, Apis mellifera, Bombus impatiens, and Bombus vosnesenskii—based on publicly available internal transcribed spacer (ITS) amplicon sequencing data. Additionally, we conducted whole-genome analyses of 25 cultivable fungal strains isolated from the gut of Apis spp. and Bombus spp. individuals collected from the Beijing Baihuashan National Nature Reserve. The results showed that Ascomycota was the dominant fungal phylum across all hosts, with significant differences in fungal diversity and community composition among host species. Phylogenetic analysis indicated high taxonomic consistency of isolated strains at the genus and species levels, along with diverse genome architectures. Functional annotations revealed that gut fungi were broadly involved in carbohydrate metabolism, cellular structure maintenance, and signal transduction. Notably, Metschnikowia strains exhibited significant enrichment in CAZyme families, particularly glycoside hydrolases (GH) and glycosyltransferases (GT). In addition, some strains possess biosynthetic gene clusters for secondary metabolites, such as nonribosomal peptide synthetase (NRPS) and β- lactones, which suggested potential roles in microbial competition and fungus-host interactions. This study uncovers the diversity and functions of fungal communities in bee guts, enriching our understanding of insect microbiomes and providing a theoretical foundation for pollinator health maintenance and microbiota-targeted interventions.