van Dillewijn P, Martínez-Abarca F, Toro N
Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Cientificas, Granada, Spain.
Mol Plant Microbe Interact. 1998 Aug;11(8):839-42. doi: 10.1094/MPMI.1998.11.8.839.
It has been reported that Sinorhizobium meliloti strains harboring IncQ and IncP multicopy vectors containing constitutively expressed Klebsiella pneumoniae nifA exhibit an increase in nodulation competitiveness on alfalfa (J. Sanjuan and J. Olivares, Mol. Plant-Microbe Interact. 4:365-369, 1991). In our efforts to understand the mechanisms involved, in this work, we have found that the observed enhancement on nodulation competitiveness by IncQ derivatives carrying K. pneumoniae nifA was not dependent on the plasmid-borne nifA activity but on the sensitivity of nonresistant strains to the streptomycin carried over from growth cultures. Furthermore, it was also determined that the nifA of K. pneumoniae on an IncP vector does not have an effect on competitiveness.
据报道，携带含有组成型表达的肺炎克雷伯菌nifA的IncQ和IncP多拷贝载体的苜蓿中华根瘤菌菌株在苜蓿上的结瘤竞争力有所提高（J. Sanjuan和J. Olivares，《分子植物-微生物相互作用》4:365-369，1991）。在我们为了解其中涉及的机制所做的努力中，在这项工作中，我们发现携带肺炎克雷伯菌nifA的IncQ衍生物对结瘤竞争力的观察到的增强并不依赖于质粒携带的nifA活性，而是依赖于非抗性菌株对生长培养物中携带的链霉素的敏感性。此外，还确定了IncP载体上肺炎克雷伯菌的nifA对竞争力没有影响。
