PDF(Pubmed)
Abstract：
The bacterial wilt pathogen Ralstonia pseudosolanacearum (Rps) colonizes plant xylem vessels and blocks the flow of xylem sap by its biofilm (comprising of bacterial cells and extracellular material), resulting in devastating wilt disease across many economically important host plants including tomatoes. The technical challenges of imaging the xylem environment, along with the use of artificial cell culture plates and media in existing in vitro systems, limit the understanding of Rps biofilm formation and its infection dynamics. In this study, we designed and built a microfluidic system that mimicked the physical and chemical conditions of the tomato xylem vessels, and allowed us to dissect Rps responses to different xylem-like conditions. The system, incorporating functional surface coatings of carboxymethyl cellulose-dopamine, provided a bioactive environment that significantly enhanced Rps attachment and biofilm formation in the presence of tomato xylem sap. Using computational approaches, we confirmed that Rps experienced linear increasing drag forces in xylem-mimicking channels at higher flow rates. Consistently, attachment and biofilm assays conducted in our microfluidic system revealed that both seeding time and flow rates were critical for bacterial adhesion to surface and biofilm formation inside the channels. These findings provided insights into the Rps attachment and biofilm formation processes, contributing to a better understanding of plant-pathogen interactions during wilt disease development.
摘要：
细菌性枯萎病病原体Ralstoniapseudosolanacearum（Rps）定植植物木质部血管，并通过其生物膜（由细菌细胞和细胞外物质组成）阻断木质部汁液的流动，在包括西红柿在内的许多经济上重要的寄主植物中导致毁灭性的枯萎病。木质部环境成像的技术挑战，随着人造细胞培养板和培养基在现有的体外系统中的使用，限制了对Rps生物膜形成及其感染动力学的理解。在这项研究中,我们设计并建立了一个模拟番茄木质部血管的物理和化学条件的微流体系统，并使我们能够剖析Rps对不同木质部样条件的反应。系统,加入羧甲基纤维素-多巴胺的功能性表面涂层，在存在番茄木质部液的情况下，提供了显着增强Rps附着和生物膜形成的生物活性环境。使用计算方法，我们证实，在较高的流速下，Rps在木质部模拟通道中经历了线性增加的阻力。始终如一，在我们的微流体系统中进行的附着和生物膜测定表明，接种时间和流速对于细菌粘附到表面和通道内生物膜的形成至关重要。这些发现提供了对Rps附着和生物膜形成过程的见解，有助于更好地了解枯萎病发展过程中植物与病原体的相互作用。
