Laboratory of Legumes, Centre of Biotechnology of Borj-Cédria, Tunisia.
Arch Microbiol. 2012 Dec;194(12):1013-21. doi: 10.1007/s00203-012-0837-7. Epub 2012 Aug 15.
The effect of the nodule-endophytic Agrobacterium strain 10C2 on nodulation, plant growth and nodule functioning of Phaseolus vulgaris was investigated using two rhizobial strains differing in their sensitivity to the in vitro antibiosis of the Agrobacterium strain. In the case of the sensitive strain, Agrobacterium sp. 10C2 induced a significant decrease in the proportion of pink nodules, probably by an antibiosis effect leading to the reduction in the number of bacteroids and thereby a decrease in total soluble proteins, leghaemoglobin content, photosynthesis and nitrogen fixation. In this case, the Agrobacterium strain behaved like a plant pathogen and the nodule reacted by increasing guaiacol peroxidase (POX) activity, which assures some physiological processes linked to pathogen control. By contrast, in the case of the resistant strain, the proportion of pink nodules increased, and thereby total soluble proteins, leghaemoglobin content, biomass production and nitrogen fixation were enhanced. The Agrobacterium strain is regarded in this case as a plant growth-promoting rhizobacterium and the POX-pathogen reaction was not observed. There was even a decrease in superoxide dismutase activity. The results suggested also that the Agrobacterium strain may be also involved in retarding nodule senescence in the case of the resistant strain.
使用两株根瘤菌菌株研究了结节内根瘤农杆菌 10C2 菌株对菜豆结瘤、植物生长和结节功能的影响，这两株根瘤菌菌株在体外对农杆菌菌株的抗生素敏感性上存在差异。对于敏感菌株，根瘤农杆菌 sp. 10C2 导致粉红色根瘤的比例显著降低，可能是由于抗生素作用导致类菌体数量减少，从而导致总可溶性蛋白、豆血红蛋白含量、光合作用和固氮减少。在这种情况下，该农杆菌菌株表现为植物病原体，根瘤通过增加愈创木酚过氧化物酶 (POX) 活性来反应，该酶确保了与病原体控制相关的一些生理过程。相比之下，在抗性菌株的情况下，粉红色根瘤的比例增加，从而增加了总可溶性蛋白、豆血红蛋白含量、生物量生产和固氮。在这种情况下，该农杆菌菌株被认为是一种促进植物生长的根瘤菌，并且没有观察到 POX-病原体反应。超氧化物歧化酶活性甚至下降。结果还表明，在抗性菌株的情况下，该农杆菌菌株可能也参与了延缓根瘤衰老。
