| Viruses that rely on vector insects to spread among higher plants or vertebrates are called arboviruses,or insect-borne viruses.Behavioral factors such as host selection and flight rate of vector insects directly affect the spread range and rate of viral diseases.However,a large number of studies have found that both plant and animal arboviruses can manipulate the behavior of vector insects.However,the underlying molecular mechanism is still unclear.RSV mainly uses Laodelphax striatellus as a medium to spread among rice in a cyclical multiplication manner.After infection,it induces rice "cancer",namely rice stripe leaf blight,which causes a large reduction in rice production[3].The previous research of this research group showed that the venomous(RSV)Laodelphax striatellus significantly tends to healthy rice,while the tendency of non-toxic Laodelphax striatellus to healthy rice and diseased rice is not significantly different.In order to explore the molecular mechanism of this phenomenon,the following research work is carried out1.The behavioral response of the toxic and non-toxic Laodelphax striatellus to 26 kinds of rice volatiles was detected by the H-type olfactory instrument,and the terpenoid compounds α-pinene,cypressene,2-heptanol,cumene and cis-3-Hexene were found has a significant attracting effect on Laodelphax striatellus without poison,and 1-heptanol has a significant repellent effect on Laodelphax striatellus without poison.The volatile compounds α-farnesene,R(+)limonene and S(-)limonene have a significant attractant effect on the toxic Laodelphax striatellus,1-octene-3ol,citronellol and β-ionone.These volatiles have a significant repellent effect on the poisonous Laodelphax striatellus.Thus,12 active rice volatiles that caused the difference in behavior of Laodelphax striatellus with and without poison were screened out.2.Through the antenna transcriptome analysis of Laodelphax striatellus,the olfactory genes that are differentially expressed in the antennae of the venomous and non-toxic Laodelphax striatellus were screened,and the differential genes were verified by fluorescence quantitative method(qRT-PCR).The results showed that RSV infestation of Laodelphax striatellus caused the expression of odorous binding proteins LsOBP1,LsOBP2,LsOBP4 and LsOBP7 in the male antennae to be significantly higher than that of the non-toxic Laodelphax striatellus,while the LsOBP7 in the female antennae decreased significantly.Therefore,LsOBP4 and LsOBP7,which are differentially expressed in Laodelphax striatellus with and without poison,were selected as the focus of follow-up experiments.3.Obtain the full length of LsOBP4 and LsOBP7 genes by PCR technology.The recombinant proteins of LsOBP4 and LsOBP7 were purified by prokaryotic in vitro expression technology,and the binding characteristics of LsOBP4 and LsOBP7 with the above-mentioned 12 active rice volatiles were verified by fluorescence competition binding experiments.The results infer that β-ionone and R(+)limonene are mainly captured and transported by LsOBP4/7 in the olfactory organs of Laodelphax striatellus,while 1-octen-3ol and citronellol are mainly captured by LsOBP7.And transported;cis-3-hexene is mainly captured and transported by LsOBP7 in the olfactory organs of Laodelphax striatellus.The results of this paper reveal that RSV infection regulates the expression of LsOBP4 and LsOBP7 in the antennae of Laodelphax striatellus,while LsOBP4 and LsOBP7 specifically bind to the rice compounds β-ionone,R(+)limonene,1-octen-3ol,Citronellol and cis-3-hexene may cause different behavioral responses of toxic and non-toxic Laodelphax striatellus to rice compounds.The results of this research analyzed the mechanism by which plant arboviruses directly control the behavior of mediator insects,supplemented the theoretical system of the interaction of the host-mediator insect-virus three,and provided a new "insect cure" for the prevention and control of plant virus diseases."Disease prevention" strategy. |
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