Dynamic transcriptome landscape of Asian domestic honeybee (Apis cerana) embryonic development revealed by high-quality RNA sequencing

Abstract

BackgroundHoneybee development consists of four stages: embryo, larva, pupa and adult. Embryogenesis, a key process of cell division and differentiation, takes 3 days in honeybees. However, the embryonic transcriptome and the dynamic regulation of embryonic transcription are still largely uncharacterized in honeybees, especially in the Asian honeybee (Apis cerana). Here, we employed high-quality RNA-seq to explore the transcriptome of Asian honeybee embryos at three ages, approximately 24, 48 and 72 h (referred to as Day1, Day2 and Day3, respectively).ResultsNine embryo samples, three from each age, were collected for RNA-seq. According to the staging scheme of honeybee embryos and the morphological features we observed, our Day1, Day2 and Day3 embryos likely corresponded to the late stage four, stage eight and stage ten development stages, respectively. Hierarchical clustering and principal component analysis showed that same-age samples were grouped together, and the Day2 samples had a closer relationship with the Day3 samples than the Day1 samples. Finally, a total of 18,284 genes harboring 55,646 transcripts were detected in the A. cerana embryos, of which 44.5% consisted of the core transcriptome shared by all three ages of embryos. A total of 4088 upregulated and 3046 downregulated genes were identified among the three embryo ages, of which 2010, 3177 and 1528 genes were upregulated and 2088, 2294 and 303 genes were downregulated from Day1 to Day2, from Day1 to Day3 and from Day2 to Day3, respectively. The downregulated genes were mostly involved in cellular, biosynthetic and metabolic processes, gene expression and protein localization, and macromolecule modification; the upregulated genes mainly participated in cell development and differentiation, tissue, organ and system development, and morphogenesis. Interestingly, several biological processes related to the response to and detection of light stimuli were enriched in the first-day A. cerana embryogenesis but not in the Apis mellifera embryogenesis, which was valuable for further investigations.ConclusionsOur transcriptomic data substantially expand the number of known transcribed elements in the A. cerana genome and provide a high-quality view of the transcriptome dynamics of A. cerana embryonic development.Electronic supplementary materialThe online version of this article (10.1186/s12861-018-0169-1) contains supplementary material, which is available to authorized users.

An Overview of Embryogenesis: External Morphology and Transcriptome Profiling in the Hemipteran Insect Nilaparvata lugens

“…We determined that the numbers of the expressed genes and expressed transcripts increased with the increasing embryonic age ( Supplementary Table S1), which suggested the levels of embryonic transcription activity gradually increased and were consistent with gradually increased embryonic morphological differences. This expression dynamics is very similar to other insects, such as D. melanogaster (Graveley et al, 2011) and Apis cerana (Hu et al, 2018).…”

Egg‐size plasticity in Apis mellifera: Honey bee queens alter egg size in response to both genetic and environmental factors

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High-Efficiency CRISPR/Cas9-Mediated Gene Editing in Honeybee (Apis mellifera) Embryos

“…The dehydrated embryos were embedded in optimal cutting temperature (OCT) compound and then cut into 7-µm sections and placed on glass slides. Each embryo section was stained by propidium iodide (PI) with a concentration of 50 µg/mL and was immediately observed using a fluorescence microscope (Leica, Germany) as described in our previous report (Hu et al 2018).…”