SRBSDV调控白背飞虱选择病/健稻苗的分子机制

SRBSDV(Southern rice black-streaked dwarf virus) is a novel virus, Sogatella furcifera is the transmission vector of SRBSDV. In our previous study, chemotaxis and host plant orientation behavior of S. furcifera between SRBSDV-infected and healthy rice seedlings were significant different. The purpose of this study is to isolate and identify the semiochemicals of plants volatite from the SRBSDV-infected and healthy rice seedlings, to investigate SRBSDV whether induce the change of semiochemicals from rice seedlings or not; It is ascertain that SRBSDV whether injury/inhibit the antenna and olfactory celles by using GC-EAD and GC-SCR or not. OBPs genes of this insect are cloned, correlations beweent OBPs genes and host orientation behavior of this insect are elucidated; In order to elucidate the funcation of OBPs on host plant orientation of S. furcifera, prokaryotic expression of OBPs genes are performed to give OBPs, the binding characteristics of OBPs and the infochemicals are analysed. From the perspective of insect ethology, this project is to elucidate how SRBSDV manipulate the orientation behavior of S. furcifer to enhance its transmission efficiency, to illustrate the manipulation mechanism on molecular level, to explore the manipulation technique of chemical communication by inhibiting the function of OBPs, and to provide theoretical and technical bases for controlling SRBSD and its vector. Moreover, it is important and helpful to understand the interaction of SRBSDV-Vector-Rice seedlings in coevolution.

SRBSDV是白背飞虱传播的一新病毒，水稻早期感染该病毒后严重减产。课题组前期已确定该虫对病、健稻苗挥发物的趋性行为不同，即毒虫优先选择无毒苗而无毒虫倾向于选择毒苗。是因该病毒侵染改变了水稻挥发物成分，还是该病毒的侵染改变了该飞虱的嗅觉系统认知网络导致这奇特现象的发生？还不可知。本项目拟研究病、健稻苗挥发物中活性成分，探明SRBSDV诱导稻苗挥发物中信息化合物的变化；结合转录组学方法，克隆鉴定该虫OBPs基因，研究OBPs与活性成分的结合特性，阐明关键性OBPs在该虫寄主植物定位中的功能，回答上述科学问题。该研究结果将促进从行为学角度和分子水平阐明SRBSDV调控该虫趋性行为来加速该病毒传播的行为调控机制，为防控该虫和SRBSDV提供重要的理论基础和技术支持，从协同进化的角度理解有利于该病毒传播的SRBSDV-白背飞虱-水稻的互作关系。

项目主要针对感染SRBSDV的白背飞虱倾向选择健康水稻而无毒白背飞虱倾向选择病毒感染的水稻的特殊行为进行机理研究。SRBSDV的侵染改变了水稻挥发物的组分，且不同品种、不同生育期挥发物组分均具差异。从健株检测到11大类化合物共36种；从病株检测到12大类化合物共37种。病株特有挥发物12种，含量差异明显的挥发物6种。SRBSDV抑制了白背飞虱SfOBP2、SfOBP3和SfOBP11的转录表达，且SfOBP2和SfOBP11在携毒白背飞虱的触角中均被显著抑制。试验证明SfOBP2在白背飞虱对染毒水稻的识别过程中具有重要作用。研究发现，辛烷和辛醛对携毒和不携毒白背飞虱均有驱避活性，柠檬烯、苯乙酮、2-庚酮、α-法尼烯和β-紫罗兰酮对携毒和不携毒白背飞虱均有吸引活性。十一烷仅对不携毒白背飞虱有吸引活性，而己醛、反-2-己烯醇和正十四烷仅对携毒白背飞虱有吸引活性，另外，芳樟醇和2-壬烯-1-醇仅对携毒白背飞虱有驱避活性。SfOBP2、SfOBP3和SfOBP11与部分供试化合物具有较强的结合能力。白背飞虱有行为反应的化合物中，辛烷和β-紫罗兰酮与SfOBP2结合能力强，2-庚酮、苯乙酮和β-紫罗兰酮与SfOBP3结合能力强，对白背飞虱有驱避作用的化合物叶绿醇与SfOBP11有强烈的亲和力。对携毒和不携毒白背飞虱有活性差异的化合物可能是导致其对病/健水稻选择行为差异的关键化合物。本研究已发表论文9篇(SCI论文7篇)，申请发明专利1项。