Evidence for plasmid-mediated chemotaxis of Pseudomonas putida towards naphthalene and salicylate.
A naphthalene (Nap) and salicylate (Sal) degrading microorganism, Pseudomonas putida RKJ1, is chemotactic towards these compounds. This strain carries a 83 kb plasmid. A 25 kb EcoRI fragment of the plasmid contains the genes responsible for Nap degradation through Sal. RKJ5, the plasmid-cured derivative of RKJ1, is neither capable of degradation nor is chemotactic towards Nap or Sal. The recombinant plasmid pRKJ3, which contained a 25 kb EcoRI fragment, was transferred back into the plasmid-free wild-type strain RKJ5, and the transconjugant showed both degradation and chemotaxis. The recombinant plasmid pRKJ3 was also transferred into motile, plasmid-free P. putida KT2442. The resulting transconjugant (RKJ15) showed chemotaxis towards both Nap and Sal. Two mutant strains carrying deletions in pRKJ3 (in KT2442) with phenotypes Nap- Sal+ and Nap- Sal-, were also tested for chemotaxis. It was found that the Nap- Sal+ mutant strain showed chemotaxis towards Sal only, whereas the Nap- Sal- mutant strain is non-chemotactic towards both the compounds. These results suggest that the metabolism of Nap and Sal may be required for the chemotactic activity.
Samanta
S K
SK
Environmental Biotechnology Laboratory, Institute of Microbial Technology, India.
Jain
R K
RK
D002633:Chemotaxis / Q000235:genetics / Q000502:physiology*; D004785:Environmental Pollutants / Q000378:metabolism*; D009281:Naphthalenes / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics*; D016958:Pseudomonas putida / Q000235:genetics / Q000502:physiology*; D020156:Salicylic Acid / Q000378:metabolism*
D004785:Environmental Pollutants; D009281:Naphthalenes; C031721:naphthalene; D020156:Salicylic Acid