The Basic Genetic Research Of Several Species Of Nilaparvata Lugens

Brown planthopper is an important rice pest, It brings huge losses on food production every year. Brown planthopper coevolut with rice genome, the species carrying resistant gene easy to mutate and then formed new species, bring serious harm to rice. Thus, Using means of molecular methods and cytology methods to research the kinship of brown planthopper is significant. In this study, ITS sequence, Repeats sequence and chromosomes were used to study Nilaparvata lugens?BPH?.Details are as follows:1 Using DNA extraction and PCR amplification method obtained ITS sequences of all varieties brown planthoppers, got their nucleotide sequences by DNA sequencing. Through software analyze results, it can be seen that the kinship of Biotype 3?A?, Biological type 1?T?, Biotype 2?M?, Leersia infesting Nilaparvata,and lugens biotypes?J? have similar relationship. Nilaparvata bakeri?L? was distant to them compared with Nilaparvata muiri China?N?. There are three large variations in ITS1 sequence. In the case of these brown planthopper materials, compared with ITS1, ITS2 is relatively conservative, no indel of large fragments, most were radiolabeling bases variation. ITS1 of three kinds of brown planthopper have three configurations, there are same kind of ITS1 secondary structure between different biotypes. ITS1 secondary structure has four arms and an intermediate ring. ITS2 secondary structure has larger differences during brown planthopper, have four configurations, But ITS2 secondary structure of the 4 biotypes brown planthopper all consist 6 arms and an intermediate ring, Nilaparvata muiri China?N? has 5 arms and an intermediate ring, the Nilaparvata bakeri?L?has four arms and an intermediate ring. Study of kinship and evolution relationships among various brown planthopper species not only to affiliat to a more comprehensive understanding, but also more importantly provid a basis to control harms to rice. All of those were because ITS1 and ITS2 participate in the structure of the ribosome, regulate specific reaction, having a certainly influence of gene transcription.2 This Study using resuspension methods to get the chromosome preparation of mitotic and meiotic cells of field brown planthopper?mainly is biotype 2?, through observating, statisticing and corresponding analysis we found that the brown planthopper chromosome number is 30?2n = 28 + XY?, in some cells there are some chromosome missing?named Asian ploidy?and the probabililty of missing one chromosome is relatively large. Through Statistics we found that Asian ploidy is more than false polyploidy. XY chromosome distribute at the edge of the hollow ring which consisted of autosomes, X chromosome is longer than Y chromosome, length of X chromosome is about 2 times to Y chromosome. relative length of X chromosome is 6.81, relative length of Y chromosome is 3.44, the relative length occupy the 6 and 15 in the chromosome ranking. The ratio of longest and shortest chromosome?chromosome length ratio? is 3.13. Through the cytologic features studying of brown planthopper chromosome during mitosis and meiosis, we learned genetic relationships of brown planthopper, which provide very important clues to explain separate and genetic breeding behavior phenomena, and also mastered the basic karyotype situation.3 Carried high-throughput genome sequencing to Brown planthopper type 1?T?, randomly selected 51 million paired-end read sequencing to proceed analyzed, and were identified by Novak and other clustering methods of read similar base pair repeats, overlapped reading clusters?groups? by BMC Bioinformatics software. Got repeat sequences by analysis, obtained primer sequences in the primer-BLAST of NCBI. Than genomic DNA was amplified to obtain the correspond tandem repeats, and compouded synthetic probes, positioned on the chromosome of Brown planthopper type 2?M?, Hybridization results showed that CL33 has four pairs hybridization signals on the chromosomes, CL38, CL13 have two pairs hybridization signals on the chromosomes, CL55 and CL62 have one pair hybridization signal on chromosomes. Four pairs of hybridization signals of CL33 has two pairs on chromosome ends, two pairs located near the centromere. Hybridization signals of CL13, CL38, CL55, CL62 are located on the ends of chromosomes. The percentage of CL13, CL33, CL38, CL55, CL62 to total genome are 14.96%, 2.11%, 8.88%, 5.56%, 1.69%.After alignment the sequences with NCBI,we discovered that CL33 has some sequences partially overlapped to ag-75 microsatellite sequences clone of irp2 m RNA and insulin-related peptide fragments of brown planthopper. CL13 has some segments overlaped to triatomine TDAK76 clon and partial fragments of TDAK51 microsatellite sequence. 61 bp sequence of CL38 is highly similar to fragment sequence which is used to isolate NLMSRDA11 methylated in the brown planthopper, similarity is 87%, 68bp-125 bp are highly similar to fragment sequences of brown planthopper which is used to isolate NLMSRDA4 methylated. Part of CL55 is similar to partial sequences of BAC clones KNP₁159H5 of wild boar and also similar to transcriptional variation X2 m RNA fragments of transmembrane 9 superfamily member 2 of Alishan maggot gifuensis. Parts of CL62 are similar to the sequence fragment of m RNA of transcripts variation X3 which is a member of family1 member 3?mta3? transfering functions related.