| The brown planthopper (BPH, Nilapai-vata lugens Stal) is the main and most destructive pest. BPH can cause loss of rice yield, even harmful to our ecological environment sustainable development by directly sucking the phloem sap of the rice leaf sheath, as well as transmitting viruses. MicroRNA (miRNA) are small noncoding and single stranded RNAs that can regulate target gene expression via either translational repression or mRNA degradation by combining with target mRNA complementarily.We identified 10 miRNAs and chose two of them related to functional studies.1. We identified 10 miRNAs, miR-279、miR-106-5p、miR-162-3p miR-184-3p、miR-20-5p、miR-222-3p、miR-226-3p、miR-30-5p、miR-33-5p mir-60-5p by Stem-loop RT-PCR and confirmed the validation of miRNAs. The relative expressions of miRNAs in BPH each development stage were also detected.2. miRNA functional analysis tool-miR antagomir and miR agomir were used to control miR-279 and miR-184-3p. miR antagomir is the loss-function tool and miR agomir is gain-function tool. Our results showed that antagomir-279 inhibited relative expression of miR-279, at the same time increased SMS mRNA levels. agomir-279 improved relative expression of miR-279,at the same time decreased SMS mRNA levels. miR-184-3p had no effect on the transcriptional level of SMPD4.3. HPLC-MS was applied to detect sphingolipids contents and components in BPH. We found that BPH treated by antagomir-279 and agomir-184-3p caused sphingolipids contests increasing and the body weight decreasing. BPH treated by agomir-279 and antagomir-184-3p caused sphingolipids contests decreasing and no effect on body weight.4. We directly proved that miR-279 regulated SMS transcriptional level, and indirectly proved that miR-279 regulated SMS translational level. So we inferred that SMS is the target gene of miR-279. In our research we had no direct evidence to prove that SMPD4 is the target gene of miR-184-3p, but our results showed miR-184-3p may regulate SMPD4 translational level. |
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