Summary Ralstonia pseudosolanacearum, a plant pathogen responsible for bacterial wilt in numerous plant species, exhibits paradoxical growth in the host by achieving high bacterial densities in xylem sap, an environment traditionally considered nutrient‐poor. This study combined in vitro experiments and mathematical modeling to elucidate the population dynamics of R. pseudosolanacearum within plants. To simulate the xylem environment, a tomato xylem‐mimicking medium was developed. Then, a mathematical model was constructed using in vitro data and employed to simulate the dynamics of bacterial density and xylem sap composition during plant infection. The model accurately reproduced in planta experimental observations, including high bacterial densities and the depletion of glutamine and asparagine. Additionally, the model estimated the minimal number of bacteria required to initiate infection, the timing of infection post‐inoculation, the bacterial mortality rate within the plant and the rate at which bacterial putrescine is assimilated by the plant. The findings demonstrate that xylem sap can sustain high bacterial densities, provides an explanatory framework for the presence of acetate, putrescine and 3‐hydroxybutyrate in the sap of infected xylem and give clues as to the role of putrescine in the virulence of R. pseudosolanacearum.

中文翻译：

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通过数学建模揭示植物病原体 Ralstonia pseudosolanacearum 的植物种群动态


摘要 Ralstonia pseudosolanacearum 是一种导致许多植物物种中细菌枯萎病的植物病原体，通过在木质部汁液中实现高细菌密度，在宿主中表现出矛盾的生长，木质部汁液是一种传统上被认为营养贫乏的环境。本研究结合体外实验和数学建模，阐明了植物内 R. pseudosolanacearum 的种群动态。为了模拟木质部环境，开发了一种番茄木质部模拟培养基。然后，利用体外数据构建数学模型，用于模拟植物感染过程中细菌密度和木质部汁液组成的动力学。该模型在植物实验观察中准确再现，包括高细菌密度以及谷氨酰胺和天冬酰胺的消耗。此外，该模型还估计了引发感染所需的最小细菌数量、接种后感染的时间、植物内的细菌死亡率以及细菌腐胺被植物吸收的速率。研究结果表明，木质部汁液可以维持高细菌密度，为受感染木质部汁液中存在乙酸盐、腐胺和 3-羟基丁酸酯提供了解释框架，并为腐胺在假青枯霉毒力中的作用提供了线索。