Nathoo Naeem, Bernards Mark A, MacDonald Jacqueline, Yuan Ze-Chun
London Research and Development Centre, Agriculture & Agri-Food Canada; Department of Biology, University of Western Ontario.
Department of Biology, University of Western Ontario.
J Vis Exp. 2017 Jul 22(125):55955. doi: 10.3791/55955.
An experimental design mimicking natural plant-microbe interactions is very important to delineate the complex plant-microbe signaling processes. Arabidopsis thaliana-Agrobacterium tumefaciens provides an excellent model system to study bacterial pathogenesis and plant interactions. Previous studies of plant-Agrobacterium interactions have largely relied on plant cell suspension cultures, the artificial wounding of plants, or the artificial induction of microbial virulence factors or plant defenses by synthetic chemicals. However, these methods are distinct from the natural signaling in planta, where plants and microbes recognize and respond in spatial and temporal manners. This work presents a hydroponic cocultivation system where intact plants are supported by metal mesh screens and cocultivated with Agrobacterium. In this cocultivation system, no synthetic phytohormone or chemical that induces microbial virulence or plant defense is supplemented. The hydroponic cocultivation system closely resembles natural plant-microbe interactions and signaling homeostasis in planta. Plant roots can be separated from the medium containing Agrobacterium, and the signaling and responses of both the plant hosts and the interacting microbes can be investigated simultaneously and systematically. At any given timepoint/interval, plant tissues or bacteria can be harvested separately for various "omics" analyses, demonstrating the power and efficacy of this system. The hydroponic cocultivation system can be easily adapted to study: 1) the reciprocal signaling of diverse plant-microbe systems, 2) signaling between a plant host and multiple microbial species (i.e. microbial consortia or microbiomes), 3) how nutrients and chemicals are implicated in plant-microbe signaling, and 4) how microbes interact with plant hosts and contribute to plant tolerance to biotic or abiotic stresses.
模仿自然植物 - 微生物相互作用的实验设计对于阐明复杂的植物 - 微生物信号传导过程非常重要。拟南芥 - 根癌农杆菌提供了一个研究细菌致病机制和植物相互作用的优秀模型系统。先前对植物 - 农杆菌相互作用的研究很大程度上依赖于植物细胞悬浮培养、植物的人工创伤，或通过合成化学物质人工诱导微生物毒力因子或植物防御反应。然而，这些方法与植物体内的自然信号传导不同，在植物体内，植物和微生物以空间和时间方式进行识别和响应。这项工作提出了一种水培共培养系统，其中完整的植物由金属网筛支撑，并与农杆菌共培养。在这个共培养系统中，不添加合成植物激素或诱导微生物毒力或植物防御的化学物质。水培共培养系统与植物体内的自然植物 - 微生物相互作用和信号稳态非常相似。植物根系可以与含有农杆菌的培养基分离，并且可以同时系统地研究植物宿主和相互作用的微生物的信号传导和反应。在任何给定的时间点/时间段，可以分别收获植物组织或细菌进行各种“组学”分析，证明了该系统的强大功能和有效性。水培共培养系统可以很容易地用于研究：1）各种植物 - 微生物系统的相互信号传导，2）植物宿主与多种微生物物种（即微生物群落或微生物组）之间的信号传导，3）营养物质和化学物质如何参与植物 - 微生物信号传导，以及4）微生物如何与植物宿主相互作用并有助于植物对生物或非生物胁迫的耐受性。
