为探究中华蜜蜂（Apis cerana cerana）与意大利蜜蜂（Apis mellifera ligustica）幼虫的球囊菌抗性差异产生的原因，利用Venn分析、GO分类分析、KEGG代谢通路分析以及Ka/ks分析对二者的转录组进行比较研究。Venn分析结果显示，中蜂与意蜂的同源基因有17 656 个，归属于8 111 个基因家族，二者的特有基因分别有1 158和241 个，分别归属于458和86 个基因家族。GO分类结果显示，中蜂和意蜂的特有基因分别富集在38和28 个GO条目。KEGG代谢通路富集分析结果显示，中蜂和意蜂的特有基因分别富集于96和21 个代谢通路；进一步分析发现中蜂的特有基因富集在内吞作用、溶酶体、泛素介导的蛋白水解和黑化作用等4 个细胞免疫通路，以及MAPK信号通路和Toll-like受体信号通路等2 个体液免疫通路，而意蜂仅有1 个特有基因富集在MAPK信号通路。Ka/Ks分析结果显示受到强烈正向选择、弱正向选择、中性选择和负向选择的单拷贝同源基因分别有37、281、2 630和3 269 个。对受到强烈正向选择的基因进行GO分类和KEGG代谢通路富集分析，GO结果显示中蜂和意蜂的单拷贝同源基因富集的GO 条目类型相同；KEGG结果显示中蜂的单拷贝基因仅富集在氧化磷酸化。上述结果表明免疫相关基因数量的差异是二者的球囊菌抗性差异产生的重要原因之一，中蜂在与球囊菌的协同进化过程中可能通过提高能量利用从而限制球囊菌的增殖。本研究结果可为阐明中蜂及意蜂幼虫的球囊菌抗性差异产生的分子机制提供参考。

Bombyx mori cypovirus (BmCPV) is one of the major viral pathogen for silkworm, and the genome of BmCPV is composed of 10 dsRNA segments. As construction system of recombinant BmCPV (rBmCPV) is scanty, researchers achieved little progress in studying gene function of BmCPV in recent decades. Here, 10 recombinant plasmids with a full-length cDNA of viral genome segments S1-S10 containing T7 promoter were constructed. After cotransfecting the BmN cells with the mixture of 10 in vitrotranscribed RNAs, pathological changes were observed. Real-time PCR and Western blot showed viral gene vp1 and structural proteins were expressed. It is found the genome of the rBmCPV is composed of 10 dsRNA segments similar to those of wild-type BmCPV. Moreover, viral particles and polyhedron with virions can be generated in the cotransfected cells and the injected silkworm midguts. These findings confirmed the formation of infective rBmCPV. Additionally, we found viable rBmCPV was generated by cotransfecting the mixture of in vitro-transcribed S1-S9 RNAs into the cultured cells, confirming polh was not essential for BmCPV replication. Moreover, an infectious rBmCPV expressing the DsRed protein was constructed based on this system. Further investigation showed S2 and S7 segments are indispensible for viral proliferation. Our findings demonstrated the construction system of rBmCPV can be utilized for exploring viral replication and pathogenesis, and investigated method for constructing rBmCPV will certainly facilitate developing novel biopesticides and expressing exogenous gene in the midgut of silkworm.

Nosema ceranae is a unicellular fungal parasite of honey bees and causes huge losses for apiculture. Until present, no study on N . ceranae long non-coding RNAs (lncRNAs) was documented. Here, we sequenced purified spores of N . ceranae using strand-specific library construction and high-throughput RNA sequencing technologies. In total, 83 novel lncRNAs were predicted from N . ceranae spore samples, including lncRNAs, long intergenic non-coding RNAs (lincRNAs), and sense lncRNAs. Moreover, these lncRNAs share similar characteristics with those identified in mammals and plants, such as shorter length and fewer exon number and transcript isoforms than protein-coding genes. Finally, the expression of 12 lncRNAs was confirmed with RT-PCR, confirming their true existence. To our knowledge, this is the first evidence of lncRNAs produced by a microsporidia species, offering novel insights into basic biology such as regulation of gene expression of this widespread taxonomic group.

Currently, knowledge of circular RNAs (circRNAs) in insects including honeybee is extremely limited. Here, differential expression profiles and regulatory networks of circRNAs in the midguts of Apis cerana cerana workers were comprehensively investigated using transcriptome sequencing and bioinformatics. In total, 9589 circRNAs (201–800 nt in length) were identified from 8-day-old and 11-day-old workers’ midguts (Ac1 and Ac2); among them, 5916 (61.70%) A. cerana cerana circRNAs showed conservation with our previously indentified circRNAs in Apis mellifera ligucstica workers’ midguts (Xiong et al., Acta Entomologica Sinica 61:1363–1375, 2018). Five circRNAs were confirmed by RT-PCR and Sanger sequencing. Interestingly, novel_circ_003723, novel_circ_002714, novel_circ_002451, and novel_circ_001980 were highly expressed in both Ac1 and Ac2. In addition, the source genes of circRNAs were involved in 34 GO terms including organelle and cellular process and 141 pathways such as endocytosis and Wnt signaling pathway. Moreover, 55 DEcircRNAs including 34 upregulated and 21 downregulated circRNAs were identified in Ac2 compared with Ac1. circRNA-miRNA regulatory networks indicated that 1060 circRNAs can target 74 miRNAs; additionally, the DEcircRNA-miRNA-mRNA networks suggested that 13 downregulated circRNAs can bind to eight miRNAs and 29 miRNA-targeted mRNAs, while 16 upregulated circRNAs can link to 9 miRNAs and 29 miRNA-targeted mRNAs. These results indicated that DEcircRNAs as ceRNAs may play a comprehensive role in the growth, development, and metabolism of the worker’s midgut via regulating source genes and interacting with miRNAs. Notably, eight DEcircRNAs targeting miR-6001-y were likely to be key participants in the midgut development. Our findings not only offer a valuable resource for further studies on A. cerana cerana circRNA and novel insights into understanding the molecular mechanisms underlying the midgut development of eastern honeybee but also provide put

Ascosphaera apis is a widespread fungal pathogen of honeybee larvae, which causes heavy losses in apiculture. To date, knowledge about non-coding RNA (ncRNA) including circular RNA (circRNA) in A. apis is lacking. In this study, A. apis mycelia and spores were sequenced using RNA-seq technology. A total of 551 circRNAs were predicted on the basis of bioinformatic analyses, and most of the circRNAs were 200–600 bp in length, which were different from animal and plant circRNAs. In addition, the expression of six circRNAs in A. apis were confirmed using divergent and convergent PCR. Moreover, circRNA-microRNA regulation networks in A. apis were constructed, and further investigation showed that A. apis circRNAs could regulate gene expression by competitively binding miRNAs. GO and KEGG pathway enrichment analyses of the miRNAs target genes of circRNAs demonstrated that these A. apis circRNAs are likely to play key roles in metabolism, environmental response and gene expression.