Competitiveness in root colonization by Pseudomonas putida requires the rpoS gene
- 1 January 2001
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Microbiology
- Vol. 47 (1), 41-48
- https://doi.org/10.1139/w00-123
Abstract
The rpoS gene in Pseudomonas putida was essential for plant root colonization under competitive conditions from other microbes. The RpoS- mutant survived less well than the wild-type strain in culture medium, and unlike the wild-type, failed to colonize the roots in a peat matrix containing an established diverse microflora. The RpoS-deficient P. putida isolate was generated by insertion of a glucuronidase-npt cassette into the rpoS gene. The RpoS- mutant had dose-dependent increased sensitivity to oxidative stress and produced Mn-superoxide dismutase activity earlier than the parent. While extracts from wild-type P. putida stationary-phase cells contained three isozymes of catalase (CatA, CatB, and CatC), the σ38-deficient P. putida lacked CatB. These results are consistent with previous findings that CatB is induced in stationary-phase.Key words: catalase, starvation, activated oxygen species.Keywords
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