Si Qin, Luo Juan-Yan, Hu Ze, Zhang Wei, Zhou Chang-Fa
The Key Laboratory of Jiangsu Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
PLoS One. 2017 Jun 21;12(6):e0179083. doi: 10.1371/journal.pone.0179083. eCollection 2017.
Mayflies (Ephemeroptera) display many primitive characters and a unique type of metamorphosis (Prometabola). However, information on the genomes and transcriptomes of this insect group is limited. The RNA sequencing study presented here generated the first de novo transcriptome assembly of Cloeon viridulum (Ephemeroptera: Baetidae), and compared gene expression signatures among the young larva (YL), mature larva (ML), subimago (SI), and imago (IM) stages of this mayfly. The transcriptome, based on 88 Gb of sequence data, comprised a set of 81,185 high quality transcripts. The number of differentially expressed genes (DEGs) in YL vs. ML, ML vs. SI, and SI vs. IM, was 4,825, 1,584, and 1,278, respectively, according to the reads per kilobase of transcript per million mapped reads analysis, assuming a false discovery rate <0.05 and a fold change >2. Gene enrichment analysis revealed that these DEGs were enriched in the "chitin metabolic process", "germ cell development", "steroid hormone biosynthesis", and "cutin, suberine, and wax biosynthesis" pathways. Finally, the expression pattern of a selected group of candidate signature genes for Prometabola, including vestigial, methoprene-tolerant, wingless, and broad-complex were confirmed by quantitative real time-PCR analysis. The Q-PCR analysis of larval, subimaginal, and imaginal stages of C. viridulum suggests that the development of mayflies more closely resembles hemimetamorphosis than holometamorphosis.
蜉蝣目昆虫（蜉蝣）具有许多原始特征和独特的变态类型（原变态）。然而，关于这个昆虫类群的基因组和转录组的信息有限。本文所呈现的RNA测序研究生成了绿水蜉（蜉蝣目：短丝蜉科）的首个从头转录组组装，并比较了这种蜉蝣的幼虫期（YL）、成熟幼虫期（ML）、亚成虫期（SI）和成虫期（IM）之间的基因表达特征。基于88 Gb的序列数据，该转录组包含一组81,185个高质量转录本。根据每百万映射 reads 中每千碱基转录本的 reads 分析，假设错误发现率<0.05且倍数变化>2，YL与ML、ML与SI以及SI与IM之间的差异表达基因（DEG）数量分别为4,825、1,584和1,278。基因富集分析表明，这些DEG在“几丁质代谢过程”、“生殖细胞发育”、“类固醇激素生物合成”和“角质、木栓质和蜡生物合成”途径中富集。最后，通过定量实时PCR分析证实了一组选定的原变态候选特征基因的表达模式，包括残翅基因、耐甲氧普烯基因、无翅基因和宽复合体基因。绿水蜉幼虫期、亚成虫期和成虫期的Q-PCR分析表明，蜉蝣的发育更类似于不完全变态而非完全变态。
