室内饲养与野外采集的松墨天牛幼虫microRNA表达谱比较分析

【目的】昆虫随着生长环境的变化常常会有不同的生物学特性,其表观遗传调控机制研究值得关注。松墨天牛是松树萎焉病中松材线虫的媒介昆虫,但松墨天牛在实验室饲养和野外的不同条件下,其形态及发育速率有较大的区别,其表观遗传响应机制并不明确。通过比较分析microRNA表达谱揭示室内饲养和野外采集松墨天牛幼虫之间的差异,以期为松墨天牛幼虫的表观遗传研究提供参考。【方法】使用illumina Hi Seq 2000平台进行microRNA高通量测序,得到了实验室饲养和野外采集松墨天牛老熟幼虫的表皮、中肠microRNA库。鉴定保守microRNA和预测新microRNA,并对microRNA进行差异表达分析、靶基因预测、靶基因GO注释和KEGG功能富集分析。【结果】在室内饲养的松墨天牛表皮、中肠中分别鉴定出16、14个microRNA;在野外生存的天牛表皮、中肠中均鉴定出13个microRNA。与表皮相比,中肠的miRNA的表达量更高。与野外采集相比,在室内饲养天牛的microRNA表达量更高。17个microRNA表达量在室内饲养与野外采集的天牛之间有显著差异,比如novel-mir-62127、novel-mir-184731、novel-mir-290819等有明显上调,novel-mir-251851等明显下调。差异表达的miRNA的靶基因的功能主要富集在氨基糖代谢、几丁质代谢等糖代谢和甘油磷脂代谢、脂肪酸代谢等脂代谢过程。【结论】室内饲养和野外采集松墨天牛老熟幼虫的microRNA库存在明显差异,且不同的组织microRNA表达谱存在明显差异,提示经历室内恒定培养条件的松墨天牛具有表观遗传调控特征,为进一步研究松墨天牛发育、代谢的microRNA调控机制奠定了基础。

Comparative analysis of miRNA expression profiles of artificially reared and field-collected Monochamus alternatus larvae

Aim] Insects show different biological characteristics as they develop under variable environmental conditions, and their epigenetic regulatory mechanisms are worthy of study. The longhorn beetle, Monochamus alternatus is a vector of the pinewood nematode, the causal agent of the devastating pine wilt disease. Numerous studies show differences in morphology and development rate of M. alternatus larvae between laboratory and field populations, yet their epigenetic response mechanism is not clear. Therefore, this paper aims to describe the difference between these two populations by microRNA expression profiling, in order to provide a reference for epigenetic research in M. alternatus.Method]High-throughput sequencing of microRNA using the illuminaHiSeq 2000 platform resulted in the construction of microRNA libraries from two laboratory-bred and two filed-collected beetle populations. The identification of conserved microRNAs and prediction of new microRNAs was also done. In addition, differential expression of microRNA was analyzed, and the function of target genes for these miRNA was predicted by GO annotation and KEGG pathway enrichment analysis.Result] A total of 16 and 14 microRNA were identified in the epidermis and midgut of indoor-reared larvae, respectively, while 13 microRNA each were identified in the epidermis and midgut of the field-collected larvae. Compared to the epidermis, miRNA expression in the midgut was higher. Compared to the wild population, the expression of microRNA in the M. alternatus in the laboratory-reared colony was higher. Here, 17 microRNA expression levels changed significantly, such as novel-mir-62127, novel-mir-184731, novel-mir-290819 were significantly up-regulated, and novel-mir-251851 were significantly down-regulated. The function of the target gene of the differentially expressed miRNA mainly points to sugar metabolism such as amino sugar metabolism, chitin metabolism, and lipid metabolism, mainly those of glycerophospholipid and fatty acids.Conclusion] There were obvious differences in the microRNA inventory between field-collected and laboratory-bred mature larvae of M. alternatus, and the microRNA expression profiles of different tissues were also significantly different. It is suggested that M. alternatus under labratory-reared conditions has the characteristics of epigenetic regulation. This lays the foundation for further studying the microRNA regulation mechanism not only for M. alternatus'' development and metabolism, but may also uncover similar patterns of epigenetic differences between wild and laboratory populations for other insects reared for research purposes.