| Nilaparvata lugens Stal (Brown planthopper, BPH) is one of the most common pests on rice and chemical control is the main way to prevent this insect pest. A long-term chemical control not only endangers harm to the ecological environment, but also leads to a strong resistance on a lot of chemical pesticides. Therefore, a combination of different methods, such as chemical control and biological control, is of necessity by taking into account the disadvantages of adopting chemical control alone. It is necessary to get rid of the only chemical control, and make a combination of different measures for chemical and biological control.As one of the most important natural enemies of N. lugens, Cyrtorrhlnus lividlpennis plays an important role in rice planthoppers controlling. Due to the same living environment, C. lividipennis populations are also damaged during chemical control of N. lugens control easy to be hurt by chemical control of N. lugens. Hence, developing a chemical pesticides which has a significant effect on N. lugens, while harmless to the predator C. lividipennis is a kind of new idea.1. Determination of sensitivity for C. lividipennis and N. lugens to 6 insecticidesIn this dissertation, Toxic method was used for testing toxicity of 6 insecticides to nymphs of C. lividipennis and N. lugens which were collected in Nanning, Guangxi Province, in 2013. The test insects were exposed to the serial concentrations using scintillation bioassay to establish a dose-mortality relationship. The results showed that, C. lividipennis is sensitive to the 5 insecticides (Fipronil, Fenobucarb, Carbaryl, Paraoxon, Diazoxon). The sensitivity factor reached to 5.05,5.44,3.67, and 2.84, respectively. C. lividipennis sensitivity factor to fipronil was 12.81 times of N. lugens, which indicates strong sensitivity compared to other chemical pesticides.2. Cloning and analysis of two kinds of acetylcholinesterase genes in C. lividipennis.We acquired transcriptome database by RNA-seq, and designed the primers based on the database. We identified 2 AChE genes in C. lividipennis by PCR and RACE techniques. Both of them displayed the characteristics of AChEs properties and showed highly similarities to insect AChE1 and AChE2 with specific functional motifs, which indicated that two genes might encode AChE1 and AChE2 proteins respectively. Based on the identities to insect AChEs, these proteins are denominated denoted as Cl-acel and Cl-ace23. Cloning and analysis of two kinds of RDL subunits in C. lividipennis.21 GAB A receptor sequences were found in the transcriptome database of C. lividipennis. One insertion of 31 amino acids between M3 and M4 of RDL was found by comparing these sequences. These two C. lividipennis RDL subunit isoforms were identified by RT-PCR and RACE techniques. They were denoted as Cl-RDL and Cl-RDL-In.4. Differences fipronil sensitivity between C. lividipennis two RDL and the N. lugens RDLBy expressing of Cl-RDL, Cl-RDL-In and Nl-RDL in Xenopus oocytes and detected by the voltage-clamp, the sensitivity differences of these three receptors on fipronil were evaluated. As a result, Cl-RDL, Cl-RDL-In were more sensitive to fipronil than Nl-RDL. Cl-RDL-In appear certain insensitivity compared with Cl-RDL. After elution of fipronil annoying, the current response of Cl-RDL-In appeared obvious recovery. It might imply that the amino acid insertion has plays a special role in the physiological function of the RDL subunit. |
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