Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpT
<b>Background/Objectives:</b> <i>Pseudomonas entomophila</i> is a ubiquitous bacterium capable of killing insects of different orders and has become a model for host–pathogen studies and a promising tool for biological pest control. In the human pathogen <i>Pseudomonas...
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2024-10-01
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| author | Laura Sánchez-Maroto Pablo Gella Alejandro Couce |
| author_facet | Laura Sánchez-Maroto Pablo Gella Alejandro Couce |
| author_sort | Laura Sánchez-Maroto |
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| description | <b>Background/Objectives:</b> <i>Pseudomonas entomophila</i> is a ubiquitous bacterium capable of killing insects of different orders and has become a model for host–pathogen studies and a promising tool for biological pest control. In the human pathogen <i>Pseudomonas aeruginosa</i>, spontaneous resistance to fosfomycin arises almost exclusively from mutations in the glycerol-3-phosphate transporter (GlpT), the drug’s sole entry route in this species. Here, we investigated whether this specificity is conserved in <i>P. entomophila</i>, as it could provide a valuable marker system for studying mutation rates and spectra and for selection in genetic engineering. <b>Methods:</b> We isolated 16 independent spontaneous fosfomycin-resistant mutants in <i>P. entomophila</i>, and studied the genetic basis of the resistance using a combination of sequencing, phenotyping and computational approaches. <b>Results:</b> We only found two mutants without alterations in <i>glpT</i> or any of its known regulatory elements. Whole-genome sequencing revealed unique inactivating mutations in <i>phoU</i>, a key regulator of the phosphate starvation (Pho) regulon. Computational analyses identified a PhoB binding site in the <i>glpT</i> promoter, and experiments showed that <i>phoU</i> inactivation reduced <i>glpT</i> expression nearly 20-fold. While placing a sugar-phosphate transporter under the Pho regulon may seem advantageous, bioinformatic analysis shows this configuration is atypical among pseudomonads. <b>Conclusions:</b> This atypical Pho regulon control of GlpT probably reflects the peculiarities of <i>P. entomophila</i>’s habitat and lifestyle; highlighting how readily regulatory evolution can lead to the rapid divergence of resistance mechanisms, even among closely related species. |
| format | Article |
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| language | English |
| publishDate | 2024-10-01 |
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| series | Antibiotics |
| spelling | doaj-art-81dd92f3d50d4e45bf4cfb9290215d182025-08-20T01:53:48ZengMDPI AGAntibiotics2079-63822024-10-011311100810.3390/antibiotics13111008Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpTLaura Sánchez-Maroto0Pablo Gella1Alejandro Couce2Centro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM), 28223 Madrid, SpainCentro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM), 28223 Madrid, SpainCentro de Biotecnología y Genómica de Plantas (CBGP), Universidad Politécnica de Madrid (UPM), 28223 Madrid, Spain<b>Background/Objectives:</b> <i>Pseudomonas entomophila</i> is a ubiquitous bacterium capable of killing insects of different orders and has become a model for host–pathogen studies and a promising tool for biological pest control. In the human pathogen <i>Pseudomonas aeruginosa</i>, spontaneous resistance to fosfomycin arises almost exclusively from mutations in the glycerol-3-phosphate transporter (GlpT), the drug’s sole entry route in this species. Here, we investigated whether this specificity is conserved in <i>P. entomophila</i>, as it could provide a valuable marker system for studying mutation rates and spectra and for selection in genetic engineering. <b>Methods:</b> We isolated 16 independent spontaneous fosfomycin-resistant mutants in <i>P. entomophila</i>, and studied the genetic basis of the resistance using a combination of sequencing, phenotyping and computational approaches. <b>Results:</b> We only found two mutants without alterations in <i>glpT</i> or any of its known regulatory elements. Whole-genome sequencing revealed unique inactivating mutations in <i>phoU</i>, a key regulator of the phosphate starvation (Pho) regulon. Computational analyses identified a PhoB binding site in the <i>glpT</i> promoter, and experiments showed that <i>phoU</i> inactivation reduced <i>glpT</i> expression nearly 20-fold. While placing a sugar-phosphate transporter under the Pho regulon may seem advantageous, bioinformatic analysis shows this configuration is atypical among pseudomonads. <b>Conclusions:</b> This atypical Pho regulon control of GlpT probably reflects the peculiarities of <i>P. entomophila</i>’s habitat and lifestyle; highlighting how readily regulatory evolution can lead to the rapid divergence of resistance mechanisms, even among closely related species.https://www.mdpi.com/2079-6382/13/11/1008fosfomycin resistancemutation rateGlpTPho regulonpromoter evolution |
| spellingShingle | Laura Sánchez-Maroto Pablo Gella Alejandro Couce Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpT Antibiotics fosfomycin resistance mutation rate GlpT Pho regulon promoter evolution |
| title | Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpT |
| title_full | Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpT |
| title_fullStr | Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpT |
| title_full_unstemmed | Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpT |
| title_short | Novel Fosfomycin Resistance Mechanism in <i>Pseudomonas entomophila</i> Due to Atypical Pho Regulon Control of GlpT |
| title_sort | novel fosfomycin resistance mechanism in i pseudomonas entomophila i due to atypical pho regulon control of glpt |
| topic | fosfomycin resistance mutation rate GlpT Pho regulon promoter evolution |
| url | https://www.mdpi.com/2079-6382/13/11/1008 |
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