柑桔类病毒互作以及寄主响应的分子机理研究

Citrus viroid is one of the most important citrus pathogen in the world. The previous study showed that certain exocortis-like diseases in China were caused by some combination of citrus viroids except CEVd. Typical synergism between citrus viroids from Apscaviroid genus and antagonism between CBCVd and CEVd were also observed. In this study, viroid titer changes after complex infection will be tested through viroid infection clone and real-time RT-PCR. In addition, with the analysis of deep sequencing data of small RNA, we will verify whether the endogenous small RNA would be induced or depressed by viroid infection. Finally, the function of these small RNAs will be validated by citrus microarray and molecular hybridization. All of these will help us to explain the molecular mechanism of interaction between citrus viroids and establish the theoretical and technical foundation of citrus viroid pathogenesis, as well as providing new ideas for controlling of exocortis or other viroid diseases.

柑桔类病毒是在世界范围内广泛发生并可造成严重经济损失的柑桔病原物。前期研究发现在中国的柑桔产区，部分与裂皮病相类似的病害是由非CEVd的多种柑桔类病毒复合侵染造成的；苹果锈果类病毒属内的柑桔类病毒具有典型的协生作用；CBCVd对CEVd存在拮抗作用。本课题拟通过类病毒侵染性克隆的构建和实时荧光定量RT-PCR等技术，监控柑桔类病毒单独/复合侵染后积累量的变化。借助于小RNA深度测序及分析，明确柑桔类病毒单独/复合侵染后是否诱导/抑制柑桔内源小RNA通路。通过柑桔基因芯片、分子杂交等技术分析寄主基因表达差异，解释这些小RNA的功能。最终从基因沉默理论水平上解析柑桔类病毒之间拮抗作用和协生作用的分子机理。本项目的开展可为预防柑桔类病毒病害在我国发生流行提供理论依据和技术支撑，并可望为柑桔裂皮病及其它类病毒病害的防控提供新的思路。

柑桔类病毒是在世界范围内广泛发生并可造成严重经济损失的柑桔病原物。前期研究发现在中国柑桔产区，柑桔树皮裂纹类病毒(CBCVd)对柑桔裂皮类病毒(CEVd) 在田间存在拮抗作用。本课题通过CEVd和CBCVd侵染性克隆的构建和实时荧光定量PCR等技术，监控二者单独/复合侵染后积累量的变化，发现CBCVd的侵染能抑制CEVd复制积累。借助于小RNA深度测序及分析，发现CEVd和CBCVd来源的sRNA在序列同源区域显著富集。通过CEVd接种香橼3个月后转录组分析，发现寄主共有1023个基因的表达明显变化，其中基因沉默、水杨酸、基础防御等通路基因表达量上调，光合作用通路基因的表达量下降。以上结果从基因沉默理论水平解析了柑桔类病毒之间拮抗作用的分子机理。本项目的开展可为预防柑桔类病毒病害在我国发生流行提供理论依据和技术支撑，并可望为柑桔裂皮病及其它类病毒病害的防控提供新的思路。