Mithöfer Axel
Dept Biologie I der Ludwig-Maximilians-Universität München, Botanik, Menzinger Str. 67, D-80638, München, Germany
Trends Plant Sci. 2002 Oct;7(10):440-4. doi: 10.1016/s1360-1385(02)02336-1.
The symbiosis between rhizobia and legumes is characterized by the formation of dinitrogen-fixing root nodules. Although rhizobia colonize roots in a way that is reminiscent of pathogenic microorganisms, no host plant defence reactions are triggered during successful symbioses. Nevertheless, the plants obviously control the invading bacteria; failure in effective nodule formation or infections with rhizobia defective in surface polysaccharides often result in pathogenic responses. This article focuses on whether and how defence responses in effective symbiosis might be suppressed. Recent results suggest a central role for rhizobial polysaccharides acting as antagonists in the negative regulation of defence induction.
根瘤菌与豆科植物之间的共生关系以形成固氮根瘤为特征。尽管根瘤菌侵染根的方式让人联想到致病微生物，但在成功的共生过程中不会触发宿主植物的防御反应。然而，植物显然会控制入侵的细菌；有效根瘤形成失败或被表面多糖有缺陷的根瘤菌感染往往会引发致病反应。本文重点关注有效共生过程中的防御反应是否以及如何被抑制。最近的研究结果表明，根瘤菌多糖作为拮抗剂在防御诱导的负调控中发挥核心作用。
