| Many agricultural virus diseases, including the rice stripe disease and the maize rough dwarf disease, occurred widely in China recent years. These diseases were very serious and brought great damages to the crops such as rice, corn, wheat and so on. It is urgent to control the virus diseases for their wide spread and serious damage to crops. Most of these diseases were caused by the rice stripe virus (RSV), rice black-streaked dwarf virus (RBSDV) and the maize rough dwarf virus (MRDV) etc. Such viruses could not infect by mechanical friction. The main vector of transmission was the small brown planthopper (SBPH) (Laodelphex striatellus, Fallen). Once infected by virus, this insect will keep the virus for ever and bring the virus to new plants when eating the juice from them. The serious viral diseases couldn't disapeared until cutting off the spreading of virus. The key to prevention and cure of the virus diseases is the control of the vector insect.The mariner transposon belongs to the Tc1/mariner superfamily of DNA transposon and widespread in the genomes of most species of bacteria, insects, and plants etc. Although the mariner has relative simple genetic construction, it can carry out very stable and efficient transformation. The process of the mariner-mediated transformation has no relationship with the host, which makes it the focus of the research on the delivery vector of transgenic technique, and many transgenic vectors had been reconstructed successfully. It would be a novel method of controlling L.striatellus if we make use of this kind of delivery vectors for producing transgenic insects. The aims to this article are to analyze the construction and composition of the mariner transposon in order to search for a novel delivery vector on transgenic insects. The main contents are as follows:1. One pair of degeneracy primers were designed according to the high conserved regions of the mariner family's transposase. A PCR array was performed using the genomic DNA of L. striatellus in five different distrcts of Shandong province as template. Nine cloning fragments are obtained, suggesting that there are mariner-like elements in L. striatellus. Recovering the PCR products, cloning the recombinants, sequencing the target gene fragments, submitting them to the GenBank Database, nine clones of Accession No. from EU542020 to EU542028 were given.2. The nine sequences were analyzed by the application of softwares such as MEGA4, DNAMAN, Clustal X and so on. Most of the lengths of the sequences are around 430bp, 500bp and 800bp. The homology among them is from 34% to 99%, which indicating that there is much of sequence composition diversity of the mariner-like elements in L. striatellus.3. Phylogeny analysis was performed among the nine copies obtained on this study and 19 representative species of mariner-like elements in 7 subfamilies downloaded from the GenBank. The results showed that only L5qfclone493 copy belongs to subfamily of mauritiana, the other 8 copies have no obviously homology with the subfamilies so far analyzed; maybe they belong to new subfamilies, further researches remain to be studied.4. Further analysis was taken to copy L5QFclone493, with the aim of forecasting the possibility to be a delivery vector in transgenic technique and laying the foundation of controlling the planthopper by transgenic method. The analyses showed that the homology of nucleotide sequence between L5QFclone493 and mos1 is 64.15%, the homology of amino acid sequence is 55.32%. Since the transposase of L5qfclone493 mutated or deleted on the key region of the NLS (Nuclear Localization Signal) and the motif of the D,D(34)D triad, presumed that the L5QFclone493 can not encode a biological active transposase. So the L5QFclone can be only considered as endogenous mariner in the method of transgenic way of controlling L. striatellus. |
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