LIPME, INRA, CNRS, Université de Toulouse, Castanet-Tolosan, France.
Microbiologyopen. 2022 Feb;11(1):e1240. doi: 10.1002/mbo3.1240.
Ralstonia solanacearum is one of the most destructive pathogens worldwide. In the last 30 years, the molecular mechanisms at the origin of R. solanacearum pathogenicity have been studied in depth. However, the nutrition status of the pathogen once inside the plant has been poorly investigated. Yet, the pathogen needs substrates to sustain a fast-enough growth, maintain its virulence and subvert the host immunity. This study aimed to explore in-depth the xylem environment where the pathogen is abundant, and its trophic preferences. First, we determined the composition of tomato xylem sap, where fast multiplication of the pathogen occurs. Then, kinetic growth on single and mixtures of carbon sources in relation to this environment was performed to fully quantify growth. Finally, we calculated the concentration of available metabolites in the xylem sap flux to assess how much it can support bacterial growth in planta. Overall, the study underlines the adaptation of R. solanacearum to the xylem environment and the fact that the pathogen assimilates several substrates at the same time in media composed of several carbon sources. It also provides metrics on key physiological parameters governing the growth of this major pathogen, which will be instrumental in the future to better understand its metabolic behavior during infection.
青枯雷尔氏菌是世界上最具破坏性的病原体之一。在过去的 30 年中，青枯雷尔氏菌致病性的分子机制已经得到了深入研究。然而，对于病原体一旦进入植物内部的营养状况却研究甚少。然而，病原体需要底物来维持足够快的生长速度，保持其毒性并颠覆宿主的免疫能力。本研究旨在深入探讨病原体大量存在的木质部环境及其营养偏好。首先，我们确定了番茄木质部汁液的组成，病原体在其中快速繁殖。然后，我们在与该环境相关的单碳源和混合碳源上进行了动力学生长实验，以全面量化生长。最后，我们计算了木质部汁液通量中可用代谢物的浓度，以评估其在植物体内支持细菌生长的能力。总的来说，该研究强调了青枯雷尔氏菌对木质部环境的适应能力，以及病原体在由多种碳源组成的培养基中同时同化多种底物的事实。它还提供了控制该主要病原体生长的关键生理参数的度量标准，这将对未来更好地理解其感染过程中的代谢行为具有重要意义。
