{"doi":"10.1128/aem.00133-11","title":"Protection of Arabidopsis thaliana against Leaf-Pathogenic Pseudomonas syringae by Sphingomonas Strains in a Controlled Model System","abstract":"<jats:title>ABSTRACT</jats:title><jats:p>Diverse bacterial taxa live in association with plants without causing deleterious effects. Previous analyses of phyllosphere communities revealed the predominance of few bacterial genera on healthy dicotyl plants, provoking the question of whether these commensals play a particular role in plant protection. Here, we tested two of them,<jats:named-content content-type=\"genus-species\">Methylobacterium</jats:named-content>and<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>, with respect to their ability to diminish disease symptom formation and the proliferation of the foliar plant pathogen<jats:named-content content-type=\"genus-species\">Pseudomonas syringae</jats:named-content>pv. tomato DC3000 on<jats:named-content content-type=\"genus-species\">Arabidopsis thaliana</jats:named-content>. Plants were grown under gnotobiotic conditions in the absence or presence of the potential antagonists and then challenged with the pathogen. No effect of<jats:named-content content-type=\"genus-species\">Methylobacterium</jats:named-content>strains on disease development was observed. However, members of the genus<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>showed a striking plant-protective effect by suppressing disease symptoms and diminishing pathogen growth. A survey of different<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>strains revealed that most plant isolates protected<jats:named-content content-type=\"genus-species\">A. thaliana</jats:named-content>plants from developing severe disease symptoms. This was not true for<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>strains isolated from air, dust, or water, even when they reached cell densities in the phyllosphere comparable to those of the plant isolates. This suggests that plant protection is common among plant-colonizing<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>spp. but is not a general trait conserved within the genus<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>. The carbon source profiling of representative isolates revealed differences between protecting and nonprotecting strains, suggesting that substrate competition plays a role in plant protection by<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>. However, other mechanisms cannot be excluded at this time. In conclusion, the ability to protect plants as shown here in a model system may be an unexplored, common trait of indigenous<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>spp. and may be of relevance under natural conditions.</jats:p>","journal":"Applied and Environmental Microbiology","year":2011,"id":665039,"datarank":0.9637303535858084,"base_score":6.424869023905388,"endowment":6.424869023905388,"self_citation_contribution":0.9637303535858084,"citation_network_contribution":0.0,"self_endowment_contribution":0.9637303535858084,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":616,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1630573,"name":"Claudia Knief","orcid":null,"position":1,"is_corresponding":false},{"id":275359,"name":"Julia A. 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Here, we tested two of them,<jats:named-content content-type=\"genus-species\">Methylobacterium</jats:named-content>and<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>, with respect to their ability to diminish disease symptom formation and the proliferation of the foliar plant pathogen<jats:named-content content-type=\"genus-species\">Pseudomonas syringae</jats:named-content>pv. tomato DC3000 on<jats:named-content content-type=\"genus-species\">Arabidopsis thaliana</jats:named-content>. Plants were grown under gnotobiotic conditions in the absence or presence of the potential antagonists and then challenged with the pathogen. No effect of<jats:named-content content-type=\"genus-species\">Methylobacterium</jats:named-content>strains on disease development was observed. However, members of the genus<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>showed a striking plant-protective effect by suppressing disease symptoms and diminishing pathogen growth. A survey of different<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>strains revealed that most plant isolates protected<jats:named-content content-type=\"genus-species\">A. thaliana</jats:named-content>plants from developing severe disease symptoms. This was not true for<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>strains isolated from air, dust, or water, even when they reached cell densities in the phyllosphere comparable to those of the plant isolates. This suggests that plant protection is common among plant-colonizing<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>spp. but is not a general trait conserved within the genus<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>. The carbon source profiling of representative isolates revealed differences between protecting and nonprotecting strains, suggesting that substrate competition plays a role in plant protection by<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>. However, other mechanisms cannot be excluded at this time. In conclusion, the ability to protect plants as shown here in a model system may be an unexplored, common trait of indigenous<jats:named-content content-type=\"genus-species\">Sphingomonas</jats:named-content>spp. and may be of relevance under natural conditions.</jats:p>","is_dataset_classified":null,"base_score":6.424869023905388,"endowment":6.424869023905388,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"21421777","pmcid":"PMC3126462","openalex_id":"https://openalex.org/W2058105775","authors":[],"funders":[],"total_grants":0,"fwci":15.6906,"citation_percentile":0.9913581,"influential_citations":0,"citation_trend":[{"year":2012,"count":7},{"year":2013,"count":13},{"year":2014,"count":21},{"year":2015,"count":15},{"year":2016,"count":32},{"year":2017,"count":27},{"year":2018,"count":35},{"year":2019,"count":49},{"year":2020,"count":63},{"year":2021,"count":92},{"year":2022,"count":66},{"year":2023,"count":66},{"year":2024,"count":52},{"year":2025,"count":48},{"year":2026,"count":27}],"oa_status":"green","license":"https://journals.asm.org/non-commercial-tdm-license","oa_locations":[{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/3126462","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/3126462","host_type":"repository"},{"url":"https://journals.asm.org/doi/pdf/10.1128/AEM.00133-11","host_type":"publisher"},{"url":"https://doi.org/10.1128/aem.00133-11","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/21421777","host_type":"repository"}],"fields_of_study":["Plant Pathogenic Bacteria Studies","Plant-Microbe Interactions and Immunity","Legume Nitrogen Fixing Symbiosis"],"mesh_terms":["Antibiosis","DNA, Bacterial","DNA, Ribosomal","Molecular Sequence Data","Pest Control, Biological","Phylogeny","Plant Diseases","RNA, Ribosomal, 16S","Cluster Analysis","Arabidopsis","Sequence Analysis, DNA","Sphingomonas","Methylobacterium","Pseudomonas syringae","Bacterial Load"],"keywords":["Sphingomonas","Phyllosphere","Methylobacterium","Pseudomonas syringae","Biology","Microbiology","Arabidopsis thaliana","Pathogen","Virulence","Sphingomonas paucimobilis","Pseudomonas","Bacteria","Botany","Gene","Genetics","16S ribosomal RNA"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Life in Land"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[{"name":"gen"}],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-13T05:17:39.950420Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}