Many aspects of plant diseases caused by phytoplasmas are still unknown, as these pathogens are phloem restricted, uncultivable wall-less bacteria and must be studied always in association with their host. Phytoplasma transcripts are strongly underrepresented within host tissues and this poses problems for gene expression analyses. In this study, a procedure was established to infect the model plant Arabidopsis thaliana with the phytoplasma Flavescence dorée, a serious threat to European viticulture. Rates of phytoplasma infective insects and transmission efficiency to A. thaliana as well as pathogen loads were measured in different tissues of infected A. thaliana plants, and modification of phloem cell ultrastructure was observed in infected plant tissues at microscopic level. Moreover, a protocol for the application of laser microdissection to analyze plant and phytoplasma gene expression profiles in the specific colonized tissue was designed. The procedure allowed a good preservation of the plant tissue anatomy. Results showed that the extracted RNA was suitable for qualitative and quantitative RT-PCR, since both plant and pathogen transcripts, either abundant or rare ones, could be detected without any pre-amplification step. The combined use of laser microdissection approach and A. thaliana to study phytoplasmas opens the way to exploit biological, molecular and bioinformatic tools available for the model plant and to elucidate key pathways of the infection mechanisms of these important plant pathogen.

由于植物原虫引起的植物病害的许多方面仍是未知的，因为这些病原体受韧皮部限制，不可培养的无壁细菌，必须始终与其宿主一起进行研究。植原体转录本在宿主组织中的表达严重不足，这为基因表达分析带来了问题。在这项研究中，建立了一种程序来用植物原质黄花病感染模型植物拟南芥，这对欧洲的葡萄栽培造成了严重威胁。在感染的拟南芥的不同组织中测定了植物质体感染昆虫的比率，对拟南芥的传播效率以及病原体负荷植株，并在微观上观察到了受侵染的植物组织中韧皮部细胞超微结构的改变。此外，设计了一个协议，应用激光显微切割技术分析特定定植组织中的植物和植物胞浆基因表达谱。该程序可以很好地保存植物组织的解剖结构。结果表明，提取的RNA适合定性和定量RT-PCR，因为无需进行任何预扩增步骤即可检测到植物和病原体的转录本，无论是丰富的还是稀有的。激光显微解剖方法与拟南芥的组合使用 对植物质原体的研究为开发可用于模型植物的生物学，分子和生物信息学工具以及阐明这些重要植物病原体感染机制的关键途径开辟了道路。