Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis Development
Isolated from desert, the nitrogen-fixing bacterium <i>Ensifer aridi</i> LMR001 is capable of survival under particularly harsh environmental conditions. To obtain insights in molecular mechanisms involved in stress adaptation, a recent study using RNAseq revealed that the RpoE2-mediated...
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MDPI AG
2022-01-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/10/2/298 |
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| author | Meryem Belfquih Abdelkarim Filali-Maltouf Antoine Le Quéré |
| author_facet | Meryem Belfquih Abdelkarim Filali-Maltouf Antoine Le Quéré |
| author_sort | Meryem Belfquih |
| collection | DOAJ |
| description | Isolated from desert, the nitrogen-fixing bacterium <i>Ensifer aridi</i> LMR001 is capable of survival under particularly harsh environmental conditions. To obtain insights in molecular mechanisms involved in stress adaptation, a recent study using RNAseq revealed that the RpoE2-mediated general stress response was activated under mild saline stress but appeared non-essential for the bacterium to thrive under stress and develop the symbiosis. Functions associated with the stress response included the metabolisms of trehalose, methionine, and inositol. To explore the roles of these metabolisms in stress adaptation and symbiosis development, and the possible regulatory mechanisms involved, mutants were generated notably in regulators and their transcriptions were studied in various mutant backgrounds. We found that mutations in regulatory genes <i>nesR</i> and <i>sahR</i> of the methionine cycle generating S-adenosylmethionine negatively impacted symbiosis, tolerance to salt, and motility in the presence of NaCl. When both regulators were mutated, an increased tolerance to detergent, oxidative, and acid stresses was found, suggesting a modification of the cell wall components which may explain these phenotypes and support a major role of the fine-tuning methylation for symbiosis and stress adaptation of the bacterium. In contrast, we also found that mutations in the predicted trehalose transport and utilization regulator ThuR and the trehalose phosphate phosphatase OtsB-encoding genes improved symbiosis and growth in liquid medium containing 0.4 M of NaCl of LMR001Δ<i>otsB</i>, suggesting that trehalose metabolism control and possibly trehalose-6 phosphate cellular status may be biotechnologically engineered for improved symbiosis under stress. Finally, transcriptional fusions of <i>gfp</i> to promoters of selected genes and expression studies in the various mutant backgrounds suggest complex regulatory interplay between inositol, methionine, and trehalose metabolic pathways. |
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| language | English |
| last_indexed | 2024-03-09T21:23:26Z |
| publishDate | 2022-01-01 |
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| spelling | doaj.art-2265fb1133f14d9facc8e88f098b848b2023-11-23T21:13:57ZengMDPI AGMicroorganisms2076-26072022-01-0110229810.3390/microorganisms10020298Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis DevelopmentMeryem Belfquih0Abdelkarim Filali-Maltouf1Antoine Le Quéré2Laboratory of Microbiology and Molecular Biology (LMBM), Department of Biology, Faculty of Sciences, University Mohammed V in Rabat, Rabat 10100, MoroccoLaboratory of Microbiology and Molecular Biology (LMBM), Department of Biology, Faculty of Sciences, University Mohammed V in Rabat, Rabat 10100, MoroccoLaboratory of Microbiology and Molecular Biology (LMBM), Department of Biology, Faculty of Sciences, University Mohammed V in Rabat, Rabat 10100, MoroccoIsolated from desert, the nitrogen-fixing bacterium <i>Ensifer aridi</i> LMR001 is capable of survival under particularly harsh environmental conditions. To obtain insights in molecular mechanisms involved in stress adaptation, a recent study using RNAseq revealed that the RpoE2-mediated general stress response was activated under mild saline stress but appeared non-essential for the bacterium to thrive under stress and develop the symbiosis. Functions associated with the stress response included the metabolisms of trehalose, methionine, and inositol. To explore the roles of these metabolisms in stress adaptation and symbiosis development, and the possible regulatory mechanisms involved, mutants were generated notably in regulators and their transcriptions were studied in various mutant backgrounds. We found that mutations in regulatory genes <i>nesR</i> and <i>sahR</i> of the methionine cycle generating S-adenosylmethionine negatively impacted symbiosis, tolerance to salt, and motility in the presence of NaCl. When both regulators were mutated, an increased tolerance to detergent, oxidative, and acid stresses was found, suggesting a modification of the cell wall components which may explain these phenotypes and support a major role of the fine-tuning methylation for symbiosis and stress adaptation of the bacterium. In contrast, we also found that mutations in the predicted trehalose transport and utilization regulator ThuR and the trehalose phosphate phosphatase OtsB-encoding genes improved symbiosis and growth in liquid medium containing 0.4 M of NaCl of LMR001Δ<i>otsB</i>, suggesting that trehalose metabolism control and possibly trehalose-6 phosphate cellular status may be biotechnologically engineered for improved symbiosis under stress. Finally, transcriptional fusions of <i>gfp</i> to promoters of selected genes and expression studies in the various mutant backgrounds suggest complex regulatory interplay between inositol, methionine, and trehalose metabolic pathways.https://www.mdpi.com/2076-2607/10/2/298<i>Ensifer aridi</i>nitrogen-fixing symbiosistrehaloseS-adenosylmethionine cyclinginositol catabolism |
| spellingShingle | Meryem Belfquih Abdelkarim Filali-Maltouf Antoine Le Quéré Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis Development Microorganisms <i>Ensifer aridi</i> nitrogen-fixing symbiosis trehalose S-adenosylmethionine cycling inositol catabolism |
| title | Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis Development |
| title_full | Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis Development |
| title_fullStr | Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis Development |
| title_full_unstemmed | Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis Development |
| title_short | Analysis of <i>Ensifer aridi</i> Mutants Affecting Regulation of Methionine, Trehalose, and Inositol Metabolisms Suggests a Role in Stress Adaptation and Symbiosis Development |
| title_sort | analysis of i ensifer aridi i mutants affecting regulation of methionine trehalose and inositol metabolisms suggests a role in stress adaptation and symbiosis development |
| topic | <i>Ensifer aridi</i> nitrogen-fixing symbiosis trehalose S-adenosylmethionine cycling inositol catabolism |
| url | https://www.mdpi.com/2076-2607/10/2/298 |
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