【目的】 球囊菌特异性地侵染蜜蜂幼虫而导致白垩病，该病造成成年蜜蜂数量的大幅下降，从而严重影响蜂蜜等产品的产量。目前，尚无利用二代测序技术研究白垩病的报道。本研究利用RNA-seq技术对正常及球囊菌胁迫后的意大利蜜蜂4日龄幼虫肠道进行深度测序，为解析宿主响应球囊菌胁迫的应答机制提供了重要的参考信息。【方法】 利用Illumina Hiseq 2500平台对对照组（AmCK）和处理组（AmT）幼虫肠道进行双端（PE125）测序；利用Perl脚本进行下机数据过滤；利用R软件进行测序饱和度分析、计算各样品之间的相关性系数；利用SOAP aligner/soap2软件将未比对上核糖体的读段（Reads）比对到意大利蜜蜂参考基因组；基于GO数据库和KEGG数据库进行GO分类和KEGG代谢通路（Pathway）富集分析。【结果】 RNA-seq共得到181 096 194条原始读段（Raw reads），经过滤得到179 078 764条有效读段（Clean reads）。差异表达基因（DEGs）分析结果显示上调与下调基因的数量分别为4和20个。DEG的基因本体论（Gene ontology，GO）分析结果显示，这些DEGs分布于10个GO分类，除归入结合（Binding）的基因和催化活性（Catalytic activity）的部分基因外，绝大多数GO分类上的基因均表现为下调。DEGs的KEGG代谢通路分析结果显示各有1个DEG分别富集在核糖体和氧化磷酸化且均下调表达。【结论】 本研究揭示了意大利蜜蜂幼虫肠道在球囊菌入侵早期的胁迫应答，为解析宿主响应球囊菌胁迫的应答机制奠定了基础。

 [Objectives]  Ascosphaera apis specifically infects honey bee larvae leading to chalkbrood disease, resulting in a serious decline in honey bee numbers and the quantity of honey bee products such as honey.  High-throughput sequencing technology has not, so far, been used to study chalkbrood. In order to reveal the molecular mechanism regulating the responses of western honey bee larvae to A. apis, we used RNA sequencing to sequence the guts of normal and A. apis-challenged 4-day-old larvae of Apis mellifera ligustica. [Methods]  Guts of an AmCK (un-treated group) and AmT (A. apis-treated group) were sequenced on an Illumina Hiseq 2500 (PE125) platform and the raw data were filtered with Perl script. Sequencing saturation analysis and Pearson correlation coefficients were calculated using Program R software. Mapping of reads to the reference genome of A. mellifera was conducted using SOAP aligner/soap2 software and GO classification and KEGG pathway enrichment analysis were carried out based on the GO and KEGG databases. [Results]  181 096 194 raw reads, and after filtration, 179 078 764 clean reads, were obtained from RNA-seq. The results of differentially expressed gene (DEG) analysis showed that the number of up- and down-regulated genes were 4 and 20, respectively. Gene ontology (GO) classification suggests these DEGs are grouped into 19 GO terms, and that among them, only several genes assigned to binding and catalytic activity were up-regulated. KEGG pathway enrichment analysis indicated that 1 and 1 DEG were enriched in ribosome and oxidative phosphorylation, respectively. [Conclusion]  Findings in the present study not only reveal larval responses of A. m. ligustica to A. apis during the early stage of infection, but also lay a foundation for illustration of the molecular mechanisms underlying host responses to A. apis.