Rhizobial bacteria colonize legume roots for the purpose of biological nitrogen fixation. A complex series of events, coordinated by host and bacterial signal molecules, underlie the development of this symbiotic interaction. Rhizobia elicit de novo formation of a novel root organ within which they establish a chronic intracellular infection. Legumes permit rhizobia to invade these root tissues while exerting control over the infection process. Once rhizobia gain intracellular access to their host, legumes also strongly influence the process of bacterial differentiation that is required for nitrogen fixation. Even so, symbiotic rhizobia play an active role in promoting their goal of host invasion and chronic persistence by producing a variety of signal molecules that elicit changes in host gene expression. In particular, rhizobia appear to advocate for their access to the host by producing a variety of signal molecules capable of suppressing a general pathogen defense response.

中文翻译：

---

共生慢性感染的分子决定因素。

根瘤菌在豆科植物的根部定植，以生物固氮的目的。由宿主和细菌信号分子协调的一系列复杂事件是这种共生相互作用发展的基础。根瘤菌引起新的根器官的新生，在它们中建立了慢性细胞内感染。豆科植物允许根瘤菌侵入这些根部组织，同时控制感染过程。一旦根瘤菌获得了进入其宿主的细胞内通道，豆类植物也会强烈影响固氮所需的细菌分化过程。即使如此，共生根瘤菌通过产生引起宿主基因表达变化的多种信号分子，在促进其宿主侵袭和长期持久性目标中发挥着积极作用。特别是，