| Western flower thrips Frankliniella occidentalis, as a major worldwide pest, which primarily through direct feeding on crops and spread the virus cause harm, is a dangerous invasive species. Its succession occurrence and causing serious harm were reported in Zhejiang, Yunnan province and so on in China. The difficulty of prevention and control have increased because of its small individual and strong concealment, both nymphs and adult's harmful for crops, nymphs' harmful in flowers, adult's fecundity in plant tissue and so on. Moreover, strong resistance to chemical pesticide were resulted because of their frequent chemical pesticide to prevent in west flower thrips. And now using commonly control method has been difficult to effectively control the damage. At present,on the point of environmental protection and ecological, producing a large number of green pollution-free vegetables and flowers, the adult stage was becoming the key to prevention and treatment period. So we speculated exploring new way of prevention and control for west flower thrips may be based on its chemical ecology and behavioral research prevention technology. On the basis of previous studies, in this topic, active compounds combination were further screened,which were applied to field practice west to traps flower thrips combined with blue plate; According to the insect mainly rely on the antenna looking for host plant odour, the distribution and ultrastructure of sensilla on the antenna, of Frankliniella occidentalis (western flower thrips) nymph,pupa and adult were observed under scanning electron microscope; A cDNA library from antennae of F. occidentalis were constructed, and one chemosensory protein (FoCSP) gene and one pheromone binding protein (FoPBP)gene were cloned by RT-PCR (Real-time PCR) and analysis of expression of proteins of F. occidentalis in male and female adult various organizations of different development stages. and these two genes so as to better analyze the prevention and control of the west flower thrips provide theoretical basis and technical support. The main results are as follows:1. the olfactory response of west flower thrips to hostplant volatilesIn olfactometer bioassays, different physiological stage were tested to hostplant volatiles,and the results show that compared with paraffin oil, west flower thrips were attracted significantly by twelve combinations from host plant volatiles. The twelve kinds of combination were combined with blue plate in the carnations garden to trap F. occidentalis, data statistics analysis showed that some combination traps more west flower thrips significantly than contrast.2 Observation of antennal sensilla of Frankliniella occidentalis with scanning electron microscopy.The distribution and ultrastructure of sensilla on the antenna, of Frankliniella occidentalis (western flower thrips) nymph pupa and adult were observed under scanning electron microscope. The antennae contain four types of antennal sensilla, namely, sensilla trichodea, sensilla basiconica (including six subtypes:Bâ… -Bâ…¥), sensilla U-shaped, sensilla cheatica (including three subtypes:CHâ… -CHâ…¢), The length and the segment number of antenna, the number and types of sensilla are significant difference with the development of nymph, the number and types of pupa were least,while which of the adult were most, and sensilla U-shaped was only found on the adult antenna, etc. Except the length and the tip of the antennae and the L sensilla basiconca and sensilla cheatica, the types, number and distribution of sensilla had no significant difference between female and male F. occidentalis.3. Molecular characterization and expression pattern of olfactory related protein genes from west flower thrips F. occidentalis.F. occidentalis antennal cDNA library was constructed and the quality of the cDNA library were identified. We describe the identification and characterization of new cDNAs encoding one chemosensory protein (FoCSP1) gene and one pheromone binding protein (FoPBP1)gene from the antenna of west flower thrips, F. occidentalis, by RT-PCR and RACE. The sequence of nucleotides was 405bp and 417bp stretches respectively. The deduced amino acid sequences of FoCSP1 and FoPBP1 revealed mature proteins of 134 and 138 amino acids, respectively, with six cysteine residues in conserved positions relative to other known CSPs and PBPs. The alignment of the mature FoCSPl and FoPBPl with other insect CSPs and PBPs showed no high sequence identity with other full-length sequences from GenBank. RT-PCR analysis revealed that FoCSP1 could expressed not only in antennae but also in other tissues such as head, leg, abdomen and wing. But we found that FoPBPl was largest amount expressed in antennae, and only extremely trace of expressed in other tissues such leg and wing,and didn't expressed in abdomen. Real-time PCR analysis revealed that the expression levels of FoPBP1 and FoCSPl were changed according to different sex, age and tissues. For above, the general trend is:the expression levels of FoCSP1 was a gradually increasing quantity of the trend with the growth of male and female. And the expression levels of FoPBPl were highest of whole period in female emergence 0-5d, while the highest in 20 days with male. |
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