根瘤菌与植物的共生关系。
The Rhizobium-plant symbiosis.
作者信息
van Rhijn P, Vanderleyden J
机构信息
F.A. Janssens Laboratory of Genetics, KU Leuven, Heverlee, Belgium.
出版信息
Microbiol Rev. 1995 Mar;59(1):124-42. doi: 10.1128/mr.59.1.124-142.1995.
Rhizobium, Bradyrhizobium, and Azorhizobium species are able to elicit the formation of unique structures, called nodules, on the roots or stems of the leguminous host. In these nodules, the rhizobia convert atmospheric N2 into ammonia for the plant. To establish this symbiosis, signals are produced early in the interaction between plant and rhizobia and they elicit discrete responses by the two symbiotic partners. First, transcription of the bacterial nodulation (nod) genes is under control of the NodD regulatory protein, which is activated by specific plant signals, flavonoids, present in the root exudates. In return, the nod-encoded enzymes are involved in the synthesis and excretion of specific lipooligosaccharides, which are able to trigger on the host plant the organogenic program leading to the formation of nodules. An overview of the organization, regulation, and function of the nod genes and their participation in the determination of the host specificity is presented.
根瘤菌属、慢生根瘤菌属和固氮根瘤菌属的细菌能够在豆科宿主植物的根或茎上诱导形成一种独特的结构，即根瘤。在这些根瘤中，根瘤菌将大气中的N2转化为氨供植物利用。为了建立这种共生关系，植物和根瘤菌在相互作用早期会产生信号，并且这些信号会引发两个共生伙伴的不同反应。首先，细菌结瘤（nod）基因的转录受NodD调节蛋白的控制，该蛋白被存在于根分泌物中的特定植物信号——类黄酮激活。作为回报，nod编码的酶参与特定脂寡糖的合成和分泌，这些脂寡糖能够在宿主植物上触发导致根瘤形成的器官发生程序。本文概述了nod基因的组织、调控和功能，以及它们在宿主特异性决定中的作用。
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