Type IV pili are involved in plant-microbe and fungus-microbe interactions
Type IV pili are involved in plant-microbe and fungus-microbe interactions
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DOI：
10.1046/j.1365-2958.1998.01010.x
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发表时间：
1998-10-01
影响因子：
3.6
通讯作者：
Reinhold-Hurek, B
中科院分区：
文献类型：
--
作者：
Dörr, J;Hurek, T;Reinhold-Hurek, B
细菌对真核细胞的粘附对于许多动物和人类病原体（例如淋病奈瑟菌和铜绿假单胞菌）的感染起始是必需的。粘附介导的IV型pill（由菌毛蛋白亚基形成的丝状表面附属物）是关键的毒力因子。在这里，我们报告了IV型菌毛依赖性粘附也参与植物-细菌和真菌-细菌的相互作用。固氮内生细菌Azoarcus sp，可以感染水稻的根部并系统地传播到地上部而不引起植物病害的症状。在固体培养基上形成丸剂依赖于pilAB基因座。PilA编码一种异常短（6.4kDa）的推定菌毛蛋白前体，其与铜绿假单胞菌IV型菌毛蛋白的保守N-末端显示100%同源性。PilB编码一个14.2kDa的多肽，与大肠杆菌I型菌毛的一个组分FimF相似。免疫荧光研究发现，PilB被挤出细胞表面，因此，它可能是菌毛组装复合物或菌毛本身的一部分。此外，这两个基因是必要的细菌粘附到菌丝体的子囊菌，这是从同一根际分离的细菌。在与真菌的共培养中，固氮菌属形成复杂的胞质膜，重氮体，这与有效的固氮有关。粘附到菌丝体似乎是这个过程的关键，因为重氮体不存在，并且在共培养中pilAB突变体的固氮速率降低。
Adherence of bacteria to eukaryotic cells is essential for the initiation of infection in many animal and human pathogens, e.g. Neisseria gonorrhoeae and Pseudomonas aeruginosa, Adhesion-mediating type IV pill, filamentous surface appendages formed by pilin subunits, are crucial virulence factors. Here, we report that type IV pilus-dependent adhesion is also involved in plant-bacteria and fungus-bacteria interactions, Nitrogen-fixing, endophytic bacteria, Azoarcus sp,, can infect the roots of rice and spread systemically into the shoot without causing symptoms of plant disease. Formation of pill on solid media was dependent on the pilAB locus. PilA encodes an unusually short (6.4 kDa) putative pilin precursor showing 100% homology to the conserved N-terminus of the Pseudomonas aeruginosa type IV pilin. PilB encodes for a 14.2 kDa polypeptide showing similarity to FimF, a component of type I fimbriae of Escherichia coli, It was found to be extruded beyond the cell surface by immunofluorescence studies, and it may, therefore, be part of a pilus assembly complex or the pilus itself, Both genes are involved in the establishment of bacteria on the root surface of rice seedlings, as detected by fluorescence microscopy. Moreover, both genes are necessary for bacterial adhesion to the mycelium of an ascomycete, which was isolated from the same rhizosphere as the bacteria. In co-culture with the fungus, Azoarcus sp. forms complex intracytoplasmic membranes, diazosomes, which are related to efficient nitrogen fixation, Adhesion to the mycelium appears to be crucial for this process, as diazosomes were absent and nitrogen fixation rates were decreased in pilAB mutants in co-culture.