Abstract: 【Aim】 This study aims to provide theoretical and experimental bases for exploring the mechanism of microRNA (miRNA) regulation on the growth, development and reproduction of Nilaparvata lugens by clarifying the expression and sequences of five miRNAs obtained in the previous identification and determining the expression profiles of the five miRNAs in different developmental stages and adult tissues of N. lugens. 【Methods】 The expression and sequence authenticity of five miRNAs (miR-1a-3p, miR-71-3p, miR-184-3p, miR-190-5p and miR-281-5p) of N. lugens were proved by Stem-loop RT-PCR and Sanger sequencing, respectively. The expression levels of the five miRNAs in different developmental stages (eggs, 1st-5th instar nymphs, female and male adults), 1-5-day-old female adults, and tissues (head, thorax, abdomen, leg, wing, midgut, Malpighian tubules and ovary) of female adults of N. lugens were detected by qRT-PCR. Overexpression and inhibition of the five miRNAs were conducted by injecting miRNA agomir and antagomir into the female adults of N. lugens, respectively.【Results】Stem-loop RT-PCR and Sanger sequencing results showed that miR-1a-3p, miR-71-3p, miR-184-3p, miR-190-5p and miR-281-5p truly exist and are expressed in N. lugens. Developmental expression profile analysis showed that miR-1a-3p and miR-71-3p were expressed in the whole developmental stages of N. lugens, and were highly expressed in male adults and 2nd instar nymphs, respectively. The relative expression levels of miR-184-3p and miR-281-5p were the highest in female adults and male adults of N. lugens, but were lower in eggs and nymphs and the relative expression levels of miR-184-3p and miR-281-5p between eggs and nymphs had no significant difference. The expression level of miR-190-5p in eggs was significantly higher than those in the other developmental stages. The expression level of miR-1a-3p in the 4-day-old female adult decreased significantly, those of miR-71-3p and miR-184-3p in the 3-day-old female adult were the highest, and those of miR-190-5p and miR-281-5p in the 1-day-old female adult were higher, and those of miR-190-5p and miR-281-5p in the female adult significantly decreased from 2- to 4-day-old. Tissue expression profile analysis showed that miR-1a-3p was significantly highly expressed in the leg and ovary, and miR-71-3p was highly expressed specifically in the ovary of female adults. The expression level of miR-184-3p in the midgut was the highest, followed by in the ovary. miR-190-5p and miR-281-5p showed the highest expression levels in the wing, followed by in the head and thorax (miR-190-5p) and midgut and ovary (miR-281-5p). After injection of miRNA agomir, the expression levels of the five miRNAs were significantly up-regulated as compared with those of the negative control. After injection of miRNA inhibitors, the expression level of miR-281-5p was significantly up-regulated as compared with that of the negative control, and the expression levels of the other four miRNAs were significantly down-regulated as compared with those of the negative control. 【Conclusion】 The five miRNAs may play a regulatory role in the growth, development and reproduction of N. lugens. The results provide a genetic reference and basic premise for further studies on miRNA function against N. lugens.

Key words: Nilaparvata lugens, miRNA, expression profile, growth, development, reproduction