Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology
The role of auxin in plant–microbe interaction has primarily been studied using indole-3-acetic acid (IAA)-producing pathogenic or plant-growth-promoting bacteria. However, the IAA biosynthesis pathway in bacteria involves indole-related compounds (IRCs) and intermediates with less known functions....
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MDPI AG
2022-03-01
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| Loạt: | Plants |
| Những chủ đề: | |
| Truy cập trực tuyến: | https://www.mdpi.com/2223-7747/11/6/721 |
| _version_ | 1827626438809878528 |
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| author | Sarah Gilbert Alexander Poulev William Chrisler Kenneth Acosta Galya Orr Sarah Lebeis Eric Lam |
| author_facet | Sarah Gilbert Alexander Poulev William Chrisler Kenneth Acosta Galya Orr Sarah Lebeis Eric Lam |
| author_sort | Sarah Gilbert |
| collection | DOAJ |
| description | The role of auxin in plant–microbe interaction has primarily been studied using indole-3-acetic acid (IAA)-producing pathogenic or plant-growth-promoting bacteria. However, the IAA biosynthesis pathway in bacteria involves indole-related compounds (IRCs) and intermediates with less known functions. Here, we seek to understand changes in plant response to multiple plant-associated bacteria taxa and strains that differ in their ability to produce IRCs. We had previously studied 47 bacterial strains isolated from several duckweed species and determined that 79% of these strains produced IRCs in culture, such as IAA, indole lactic acid (ILA), and indole. Using <i>Arabidopsis thaliana</i> as our model plant with excellent genetic tools, we performed binary association assays on a subset of these strains to evaluate morphological responses in the plant host and the mode of bacterial colonization. Of the 21 tested strains, only four high-quantity IAA-producing <i>Microbacterium</i> strains caused an auxin root phenotype. Compared to the commonly used colorimetric Salkowski assay, auxin concentration determined by LC–MS was a superior indicator of a bacteria’s ability to cause an auxin root phenotype. Studies with the auxin response mutant <i>axr1-3</i> provided further genetic support for the role of auxin signaling in mediating the root morphology response to IAA-producing bacteria strains. Interestingly, our microscopy results also revealed new evidence for the role of the conserved <i>AXR1</i> gene in endophytic colonization of IAA-producing <i>Azospirillum baldaniorum</i> Sp245 via the guard cells. |
| first_indexed | 2024-03-09T12:55:44Z |
| format | Article |
| id | doaj.art-36be92a09ede47f59e7c1f536475b1c1 |
| institution | Directory Open Access Journal |
| issn | 2223-7747 |
| language | English |
| last_indexed | 2024-03-09T12:55:44Z |
| publishDate | 2022-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Plants |
| spelling | doaj.art-36be92a09ede47f59e7c1f536475b1c12023-11-30T22:00:08ZengMDPI AGPlants2223-77472022-03-0111672110.3390/plants11060721Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant MorphologySarah Gilbert0Alexander Poulev1William Chrisler2Kenneth Acosta3Galya Orr4Sarah Lebeis5Eric Lam6Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USADepartment of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USAEnvironmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USADepartment of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USAEnvironmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USADepartment of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USADepartment of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USAThe role of auxin in plant–microbe interaction has primarily been studied using indole-3-acetic acid (IAA)-producing pathogenic or plant-growth-promoting bacteria. However, the IAA biosynthesis pathway in bacteria involves indole-related compounds (IRCs) and intermediates with less known functions. Here, we seek to understand changes in plant response to multiple plant-associated bacteria taxa and strains that differ in their ability to produce IRCs. We had previously studied 47 bacterial strains isolated from several duckweed species and determined that 79% of these strains produced IRCs in culture, such as IAA, indole lactic acid (ILA), and indole. Using <i>Arabidopsis thaliana</i> as our model plant with excellent genetic tools, we performed binary association assays on a subset of these strains to evaluate morphological responses in the plant host and the mode of bacterial colonization. Of the 21 tested strains, only four high-quantity IAA-producing <i>Microbacterium</i> strains caused an auxin root phenotype. Compared to the commonly used colorimetric Salkowski assay, auxin concentration determined by LC–MS was a superior indicator of a bacteria’s ability to cause an auxin root phenotype. Studies with the auxin response mutant <i>axr1-3</i> provided further genetic support for the role of auxin signaling in mediating the root morphology response to IAA-producing bacteria strains. Interestingly, our microscopy results also revealed new evidence for the role of the conserved <i>AXR1</i> gene in endophytic colonization of IAA-producing <i>Azospirillum baldaniorum</i> Sp245 via the guard cells.https://www.mdpi.com/2223-7747/11/6/721duckweed-associated bacteria<i>Microbacterium</i><i>Azospirillum</i>auxin<i>AXR1</i>Arabidopsis |
| spellingShingle | Sarah Gilbert Alexander Poulev William Chrisler Kenneth Acosta Galya Orr Sarah Lebeis Eric Lam Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology Plants duckweed-associated bacteria <i>Microbacterium</i> <i>Azospirillum</i> auxin <i>AXR1</i> Arabidopsis |
| title | Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology |
| title_full | Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology |
| title_fullStr | Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology |
| title_full_unstemmed | Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology |
| title_short | Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology |
| title_sort | auxin producing bacteria from duckweeds have different colonization patterns and effects on plant morphology |
| topic | duckweed-associated bacteria <i>Microbacterium</i> <i>Azospirillum</i> auxin <i>AXR1</i> Arabidopsis |
| url | https://www.mdpi.com/2223-7747/11/6/721 |
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