MicroRNA dataset of normal and Nosema ceranae-infected midguts of Apis cerana cerana workers

AbstractMicroRNAs (miRNAs) are endogenous small noncoding RNAs that post transcriptionally regulate gene expression and are involved in many biological processes including host-pathogen interactions. However, the potential role of miRNAs in the responses of eastern honeybees to Nosema ceranae invasion is completely unknown. Here, the expression profiles and differentially expressed miRNAs (DEmiRNAs) in the midguts of Apis cerana cerana workers 7 and 10 days post infection (dpi) with N. ceranae were investigated via small RNA sequencing and bioinformatics. In total, 529 miRNAs highly conserved between various species and 25 novel miRNAs with varied expressions were identified for the first time. In addition, stem-loop RT-PCR confirmed the expression of 16 predicted miRNAs, validating their existence. Eight up-regulated miRNAs and six down-regulated miRNAs were detected in midguts at 7 dpi, while nine and three miRNAs were significantly up-regulated and down-regulated, respectively, in midguts at 10 dpi. In addition, Venn analysis showed that five DEmiRNAs were shared, while nine and seven DEmiRNAs were specifically expressed in midguts at 7 and 10 dpi, respectively. Gene ontology analysis suggested that a portion of the DEmiRNAs and corresponding target genes were involved in various biological processes, cellular components, and molecular functions including immune system processes and response to stimulus and signaling. Moreover, KEGG pathway analysis shed light on the potential functions of some DEmiRNAs in the regulation of target genes engaged in material and energy metabolism, cellular immunity such as endocytosis and phagosome, and the humoral immune system, including the Jak-STAT and MAPK signaling pathways. Further investigation demonstrated a complex regulation network between DEmiRNAs and their target mRNAs, with miR-598-y, miR-252-y, miR-92-x and miR-3654-y at the center of the network, implying their key parts in host responses. This comprehensive miRNA transcriptome analysis demonstrated that N. ceranae invasion influenced the expression of miRNAs in the midguts of A. c. ceranae workers; the results can not only facilitate future exploration of the regulatory roles and mechanisms of miRNAs in hosts’ responses, especially their immune responses to N. ceranae, but also provide potential candidates for further investigation of the molecular mechanisms underlying eastern honeybee-microsporidian interactions.

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Impact of Nosema ceranae invasion on sucrose solution consumption, midgut epithelial cell structure, and lifespan of Apis cerana cerana workers

10.1101/2022.01.09.475580 ◽

2022 ◽

Author(s):

Qi Long ◽

Minghui Sun ◽

Xiaoxue Fan ◽

Wende Zhang ◽

Dingding Zhou ◽

...

Keyword(s):

Epithelial Cell ◽

Epithelial Cells ◽

Sucrose Solution ◽

Cell Structure ◽

Apis Cerana ◽

Nosema Ceranae ◽

Apis Cerana Cerana ◽

Midgut Epithelial Cell ◽

Asian Honeybee ◽

Spore Load

Nosema ceranae is an intracellular fungal parasite for honeybees, leading to chronic disease named bee nosemosis with worldwide distribution. Asian honeybee (Apis cerana) is the original host for N. ceranae, but the impact of N. ceranae infection on A. cerana physiology is largely unknown. In this current work, workers of Apis cerana cerana, a subspecies of Asian honeybee, were artificially inoculated with N. ceranae spores and reared under lab conditions, followed by detection of fungal spore load as well as host sucrose solution consumption, midgut epithelial cell structure, and lifespan. The result of spore counting suggested that the spore load in the host midgut decreased significantly during 1 dpi-2 dpi, whereas that displayed an elevated trend among 2 dpi-13 dpi. The sucrose solution consumption of workers in N. ceranae-inoculated groups among 1 dpi-20 dpi was always higher than that of workers in un-inoculated groups; additionally, the difference of sucrose solution consumption between these two groups at 4 dpi, 5 dpi, and 13 dpi was of significance. Based on microscopic observation of paraffin sections, darkly stained parasites were clearly detected in the midgut epithelial cells of N. ceranae-inoculated workers at 7 dpi-10 dpi, whereas no parasite was observed in those of un-inoculated workers. In addition, the boundaries of un-inoculated host epithelial cells were intact and the darkly stained nucleus were clear, while the boundaries of midgut epithelial cells of N. ceranae-inoculated workers were blurred, the nucleus were almost disappeared, and the nucleic acid substances were diffused. Moreover, the survival rates of workers in both N. ceranae-inoculated groups and un-inoculated groups at 1 dpi-5 dpi were pretty high and then started to decrease at 5 dpi; the survival rate of workers in N. ceranae-inoculated groups was always lower than that in un-inoculated groups, with significant difference between these two groups during 11 dpi-20 dpi. These results together indicate that the quantity of fungal spores continuously elevated with the microsporidian multiplication, causing energetic stress for workers and host cell structure damage, which further negatively affected the host lifespan. Our findings offer a solid basis not only for exploring the molecular mechanism underlying N. ceranae infection but also for investigating the interaction between N. ceranae and eastern honeybee.

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