Table_2_Genome-Wide Screening and Functional Analysis Reveal That the Specific microRNA nlu-miR-173 Regulates Molting by Targeting Ftz-F1 in Nilaparvata lugens.XLS

Background: Molting is a crucial physiological behavior during arthropod growth. In the past few years, molting as well as chitin biosynthesis triggered by molting, is subject to regulation by miRNAs. However, how many miRNAs are involved in insect molting at the genome-wide level remains unknown.
Results: We deeply sequenced four samples obtained from nymphs at the 2nd−3rd and 4th−5th instars, and then identified 61 miRNAs conserved in the Arthropoda and 326 putative novel miRNAs in the brown planthopper Nilaparvata lugens, a fearful pest of rice. A total of 36 mature miRNAs with significant different expression levels at the genome scale during molting, including 19 conserved and 17 putative novel miRNAs were identified. After comparing the expression profiles, we found that most of the targets of 36 miRNAs showing significantly differential expression were involved in energy and hormone pathways. One of the 17 putative novel miRNAs, nlu-miR-173 was chosen for functional study. nlu-miR-173 acts in 20-hydroxyecdysone signaling through its direct target, N. lugens Ftz-F1(NlFtz-F1), a transcription factor. Furthermore, we found that the transcription of nlu-miR-173 was promoted by Broad-Complex (BR-C), suggesting that its involvement in the 20-hydroxyecdysone pathway contributes to proper molting function.
Conclusion: We provided a comprehensive resource of miRNAs associated with insect molting and identified a novel miRNA as a potential target for pest control.

背景：蜕皮（molting）是节肢动物（arthropod）生长过程中的关键生理行为。近年来，蜕皮及其触发的几丁质生物合成（chitin biosynthesis）均受微小RNA（miRNAs）的调控。然而，在全基因组层面，究竟有多少种miRNAs参与昆虫蜕皮过程，目前尚未明确。
结果：我们对采集自2~3龄及4~5龄若虫的4份样本开展深度测序，在水稻重大害虫褐飞虱（Nilaparvata lugens）中，共鉴定出61种节肢动物门保守的miRNAs，以及326条潜在新型miRNAs。最终鉴定出36种在蜕皮阶段全基因组范围内表达水平存在显著差异的成熟miRNAs，其中19种为保守型miRNAs，17种为潜在新型miRNAs。通过对比表达谱（expression profiles），我们发现这36种差异表达miRNAs的绝大多数靶基因均参与能量代谢与激素信号通路。我们选取17种潜在新型miRNAs中的nlu-miR-173开展功能研究，发现其通过直接靶向转录因子（transcription factor）褐飞虱Ftz-F1（NlFtz-F1）参与20-羟基蜕皮酮（20-hydroxyecdysone）信号通路。进一步研究发现，Broad-Complex（BR-C）可促进nlu-miR-173的转录，表明其通过参与20-羟基蜕皮酮通路以确保正常蜕皮功能的实现。
结论：本研究构建了与昆虫蜕皮相关的miRNAs综合资源库，并鉴定出一种可作为害虫防治（pest control）潜在靶标的新型miRNA。