Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization
ABSTRACT Horizontal gene transfer (HGT) is a fundamental evolutionary process that plays a key role in bacterial evolution. The likelihood of a successful transfer event is expected to depend on the precise balance of costs and benefits resulting from pathway acquisition. Most experimental analyses...
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American Society for Microbiology
2025-01-01
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| Online Access: | https://journals.asm.org/doi/10.1128/mbio.03016-24 |
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| author | Stephan Christel Alyssa A. Carrell Leah H. Hochanadel Manuel I. Villalobos Solis Paul E. Abraham Sara S. Jawdy Julie E. Chaves Nancy L. Engle Timkhite-Kulu Berhane Tao Yao Jin-Gui Chen Wellington Muchero Timothy J. Tschaplinski Melissa A. Cregger Joshua K. Michener |
| author_facet | Stephan Christel Alyssa A. Carrell Leah H. Hochanadel Manuel I. Villalobos Solis Paul E. Abraham Sara S. Jawdy Julie E. Chaves Nancy L. Engle Timkhite-Kulu Berhane Tao Yao Jin-Gui Chen Wellington Muchero Timothy J. Tschaplinski Melissa A. Cregger Joshua K. Michener |
| author_sort | Stephan Christel |
| collection | DOAJ |
| description | ABSTRACT Horizontal gene transfer (HGT) is a fundamental evolutionary process that plays a key role in bacterial evolution. The likelihood of a successful transfer event is expected to depend on the precise balance of costs and benefits resulting from pathway acquisition. Most experimental analyses of HGT have focused on phenotypes that have large fitness benefits under appropriate selective conditions, such as antibiotic resistance. However, many examples of HGT involve phenotypes that are predicted to provide smaller benefits, such as the ability to catabolize additional carbon sources. We have experimentally simulated the consequences of one such HGT event in the laboratory, studying the effects of transferring a pathway for catabolism of the plant-derived aromatic compound salicyl alcohol between rhizosphere isolates from the Pseudomonas genus. We find that pathway acquisition enables rapid catabolism of salicyl alcohol with only minor disruptions to the existing metabolic and regulatory networks of the new host. However, this new catabolic potential does not confer a measurable fitness advantage during competitive growth in the rhizosphere. We conclude that the phenotype of salicyl alcohol catabolism is readily transferable but is selectively neutral under environmentally relevant conditions. We propose that this condition is common and that HGT of many pathways will be self-limiting because the selective benefits are small.IMPORTANCEHorizontal gene transfer (HGT) is a key process in microbial evolution, but the factors limiting HGT are poorly understood. Aside from the rather unique scenario of antibiotic resistance, the evolutionary benefits of pathway acquisition are still unclear. To experimentally test the effects of pathway acquisition, we transferred a pathway for catabolism of a plant-derived aromatic compound between soil bacteria isolated from the roots of poplar trees and determined the resulting phenotypic and fitness effects. We found that pathway acquisition allowed bacteria to grow using the plant-derived compound in the laboratory, but that this new phenotype did not provide an advantage when the bacteria were reinoculated onto plant roots. These results suggest that the benefits of pathway acquisition may be small when measured under ecologically-relevant conditions. From an engineering perspective, efforts to alter microbial community composition in situ by manipulating catabolic pathways or nutrient availability will be challenging when gaining access to a new niche does not provide a benefit. |
| format | Article |
| id | doaj-art-94a4dad2e0db45a1bfd3b0e0c2e1188e |
| institution | DOAJ |
| issn | 2150-7511 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | American Society for Microbiology |
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| series | mBio |
| spelling | doaj-art-94a4dad2e0db45a1bfd3b0e0c2e1188e2025-08-20T02:43:47ZengAmerican Society for MicrobiologymBio2150-75112025-01-0116110.1128/mbio.03016-24Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonizationStephan Christel0Alyssa A. Carrell1Leah H. Hochanadel2Manuel I. Villalobos Solis3Paul E. Abraham4Sara S. Jawdy5Julie E. Chaves6Nancy L. Engle7Timkhite-Kulu Berhane8Tao Yao9Jin-Gui Chen10Wellington Muchero11Timothy J. Tschaplinski12Melissa A. Cregger13Joshua K. Michener14Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USABiosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USAABSTRACT Horizontal gene transfer (HGT) is a fundamental evolutionary process that plays a key role in bacterial evolution. The likelihood of a successful transfer event is expected to depend on the precise balance of costs and benefits resulting from pathway acquisition. Most experimental analyses of HGT have focused on phenotypes that have large fitness benefits under appropriate selective conditions, such as antibiotic resistance. However, many examples of HGT involve phenotypes that are predicted to provide smaller benefits, such as the ability to catabolize additional carbon sources. We have experimentally simulated the consequences of one such HGT event in the laboratory, studying the effects of transferring a pathway for catabolism of the plant-derived aromatic compound salicyl alcohol between rhizosphere isolates from the Pseudomonas genus. We find that pathway acquisition enables rapid catabolism of salicyl alcohol with only minor disruptions to the existing metabolic and regulatory networks of the new host. However, this new catabolic potential does not confer a measurable fitness advantage during competitive growth in the rhizosphere. We conclude that the phenotype of salicyl alcohol catabolism is readily transferable but is selectively neutral under environmentally relevant conditions. We propose that this condition is common and that HGT of many pathways will be self-limiting because the selective benefits are small.IMPORTANCEHorizontal gene transfer (HGT) is a key process in microbial evolution, but the factors limiting HGT are poorly understood. Aside from the rather unique scenario of antibiotic resistance, the evolutionary benefits of pathway acquisition are still unclear. To experimentally test the effects of pathway acquisition, we transferred a pathway for catabolism of a plant-derived aromatic compound between soil bacteria isolated from the roots of poplar trees and determined the resulting phenotypic and fitness effects. We found that pathway acquisition allowed bacteria to grow using the plant-derived compound in the laboratory, but that this new phenotype did not provide an advantage when the bacteria were reinoculated onto plant roots. These results suggest that the benefits of pathway acquisition may be small when measured under ecologically-relevant conditions. From an engineering perspective, efforts to alter microbial community composition in situ by manipulating catabolic pathways or nutrient availability will be challenging when gaining access to a new niche does not provide a benefit.https://journals.asm.org/doi/10.1128/mbio.03016-24horizontal gene transferplant-microbe interactionsPopulussalicylates |
| spellingShingle | Stephan Christel Alyssa A. Carrell Leah H. Hochanadel Manuel I. Villalobos Solis Paul E. Abraham Sara S. Jawdy Julie E. Chaves Nancy L. Engle Timkhite-Kulu Berhane Tao Yao Jin-Gui Chen Wellington Muchero Timothy J. Tschaplinski Melissa A. Cregger Joshua K. Michener Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization mBio horizontal gene transfer plant-microbe interactions Populus salicylates |
| title | Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization |
| title_full | Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization |
| title_fullStr | Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization |
| title_full_unstemmed | Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization |
| title_short | Catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization |
| title_sort | catabolic pathway acquisition by rhizosphere bacteria readily enables growth with a root exudate component but does not affect root colonization |
| topic | horizontal gene transfer plant-microbe interactions Populus salicylates |
| url | https://journals.asm.org/doi/10.1128/mbio.03016-24 |
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