The roles of plant roots are not merely limited to the provision of mechanical support, nutrients and water, but also include more specific roles, such as the capacity to secrete diverse chemical substances. These metabolites are actively secreted in the near root and play specific and significant functions in plant defense and communication. In this review, we detail the various preventive roles of these powerful substances in the rhizosphere with a perspective as to how plants recruit microbes as a preventive measure against other pathogenic microbes, also, briefly about how the rhizosphere can repel insect pests, and how these chemical substances alter microbial dynamics and enhance symbiotic relationships. We also highlight the need for more research in this area to detail the mode of action and quantification of these compounds in the environment and their roles in some important biological processes in microorganisms and plants.

中文翻译：

---

次生代谢物作为植物防御策略：近根区小分子的重要作用

植物根系的作用不仅限于提供机械支持、养分和水分，还包括更具体的作用，例如分泌多种化学物质的能力。这些代谢物在近根部积极分泌，在植物防御和通讯中发挥特定而重要的功能。在这篇综述中，我们详细介绍了这些强效物质在根际的各种预防作用，从植物如何招募微生物作为预防其他病原微生物的措施的角度，还简要介绍了根际如何驱除害虫，以及这些化学物质改变微生物动态并增强共生关系。