In vivo gene expression of Pseudomonas putida KT2440 in the rhizosphere of different plants.
Bottom Line: Using the IVET technology we investigated which KT2440 genes were expressed in the rhizosphere of four different plants: pine, cypress, evergreen oak and rosemary.Another 40 fusions were found to correspond to likely promoters that encode antisense RNAs of unknown function, some of which were isolated as fusions from the bacteria recovered in the rhizosphere from all of the plants, while others were specific to one or several of the plants.The results obtained in this study suggest that plant-specific signals are sensed by KT2440 in the rhizosphere and that the signals and consequent gene expression are related to the bacteria's successful establishment in this niche.
Affiliation: Bio-Iliberis Research and Development, I+D Department, 18210, Peligros, Granada, Spain.Show MeSH
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Mentions: To further investigate the putative role of the activated genes in rhizosphere adaptation in silico studies were carried out (see below), as well as a detailed analysis of the previously published information on the function of these genes. Functional analysis of the genes expressed from the promoters contained in the transcriptional fusions, revealed six main categories: metabolism, gene regulation, DNA replication and recombination, stress response, transporters, and a number of hypothetical proteins of unknown function (Fig. 4). This reinforces the hypothesis that a strict signalling and a complex network of interactions occur in the rhizosphere enabling bacteria to cope with two general problems: new nutrient sources and significant stress conditions (Hartmann et al., 2009). These categories are in agreement with those described for KT2440 in the rhizosphere of maize grown in hydroponic solution (Ramos-González et al., 2005) and sand (Matilla et al., 2007), although the genes identified in the current study are different.
Affiliation: Bio-Iliberis Research and Development, I+D Department, 18210, Peligros, Granada, Spain.