The chitin biosynthesis pathway is an important physiology process in arthropods. However, few microRNAs (miRNAs) involved in the regulation of the chitin biosynthesis pathway in insects have been reported until now. In this study, four groups of samples that either upregulated or downregulated the chitin biosynthesis pathway were collected for deep sequencing, and a total of 15 unique mature miRNAs with significantly different expression levels were found, including 11 known miRNAs and four novel miRNAs. Subsequently, we showed that miR‐2703 and its new target gene chitin synthase 1a are important for ecdysone‐induced chitin biosynthesis in Nilaparvata lugens, a serious insect pest of rice. The nymphs showed an obvious moulting defect phenotype, lower survival rate and significantly reduced chitin content after miR‐2703 feeding or injection. Furthermore, we found that the transcription level of miR‐2703 was not repressed by 20‐hydroxyecdysone signalling after Broad‐Complex (BR‐C) double‐stranded RNA (dsRNA) injection compared with the repressed levels after green fluorescent protein dsRNA injection, suggesting that the involvement of miR‐2703 in the 20‐hydroxyecdysone pathway contributes to BR‐C activity. miR‐2703 regulates the chitin biosynthesis pathway by targeting chitin synthase 1a in response to 20‐hydroxyecdysone signalling.

中文翻译：

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miR-2703通过针对褐飞虱中的几丁质合酶1a来调节几丁质的生物合成途径。

甲壳素的生物合成途径是节肢动物的重要生理过程。然而，到目前为止，很少有涉及昆虫中甲壳质生物合成途径调控的微小RNA（miRNA）的报道。在这项研究中，收集了上调或下调甲壳质生物合成途径的四组样品进行深度测序，共发现了15种表达水平明显不同的独特成熟miRNA，包括11种已知的miRNA和4种新颖的miRNA。随后，我们证明了miR‐2703及其新的靶基因几丁质合酶1a对于蜕皮激素诱导的褐飞虱的几丁质生物合成很重要。，一种严重的水稻害虫。若取食或注射miR-2703后，若虫显示出明显的蜕皮缺陷表型，较低的存活率并显着降低了几丁质含量。此外，我们发现，注射Broad-Complex（BR-C）双链RNA（dsRNA）后的20-羟基蜕皮激素信号传导与绿色荧光蛋白dsRNA注射后的抑制水平相比，miR-2703的转录水平没有受到抑制。miR-2703参与20-羟基蜕皮激素途径有助于BR-C活性。miR-2703通过针对20-羟基蜕皮激素信号转导的几丁质合酶1a来调节几丁质的生物合成途径。