{"doi":"10.1111/pce.14335","title":"Rhizobial HmuS<sub>pSym</sub> as a heme‐binding factor is required for optimal symbiosis between <i>Mesorhizobium amorphae</i> CCNWGS0123 and <i>Robinia pseudoacacia</i>","abstract":"<jats:title>Abstract</jats:title><jats:p>Nitrogen‐fixing root nodules are formed by symbiotic association of legume hosts with rhizobia in nitrogen‐deprived soils. Successful symbiosis is regulated by signals from both legume hosts and their rhizobial partners. HmuS is a heme degrading factor widely distributed in bacteria, but little is known about the role of rhizobial <jats:italic>hmuS</jats:italic> in symbiosis with legumes. Here, we found that inactivation of <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> in the symbiotic plasmid of <jats:italic>Mesorhizobium amorphae</jats:italic> CCNWGS0123 disrupted rhizobial infection, primordium formation, and nitrogen fixation in symbiosis with <jats:italic>Robinia pseudoacacia</jats:italic>. Although there was no difference in bacteroids differentiation, infected plant cells were shrunken and bacteroids were disintegrated in nodules of plants infected by the Δ<jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> mutant strain. The balance of defence reaction was also impaired in Δ<jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> strain‐infected root nodules. <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> was strongly expressed in the nitrogen‐fixation zone of mature nodules. Furthermore, the HmuS<jats:sub>pSym</jats:sub> protein could bind to heme but not degrade it. Inactivation of <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> led to significantly decreased expression levels of oxygen‐sensing related genes in nodules. In summary, <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> of <jats:italic>M. amorphae</jats:italic> CCNWGS0123 plays an essential role in nodule development and maintenance of bacteroid survival within <jats:italic>R. pseudoacacia</jats:italic> cells, possibly through heme‐binding in symbiosis.</jats:p>","journal":"Plant, Cell &amp; Environment","year":2022,"id":596732,"datarank":0.24141568686511508,"base_score":1.6094379124341003,"endowment":1.6094379124341003,"self_citation_contribution":0.24141568686511508,"citation_network_contribution":0.0,"self_endowment_contribution":0.24141568686511508,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":4,"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":722194,"name":"Le Zong","orcid":"0000-0002-7056-7497","position":1,"is_corresponding":false},{"id":1198953,"name":"Yao Liu","orcid":"0000-0003-0365-3229","position":2,"is_corresponding":false},{"id":1528397,"name":"Wenfeng Chen","orcid":null,"position":3,"is_corresponding":false},{"id":445462,"name":"Juan Chen","orcid":"0000-0002-7959-335X","position":4,"is_corresponding":false},{"id":1528399,"name":"Gehong Wei","orcid":"0000-0003-0582-7210","position":5,"is_corresponding":false},{"id":1528391,"name":"Haibo Huo","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Rhizobial HmuS<sub>pSym</sub> as a heme‐binding factor is required for optimal symbiosis between <i>Mesorhizobium amorphae</i> CCNWGS0123 and <i>Robinia pseudoacacia</i>","abstract":"<jats:title>Abstract</jats:title><jats:p>Nitrogen‐fixing root nodules are formed by symbiotic association of legume hosts with rhizobia in nitrogen‐deprived soils. Successful symbiosis is regulated by signals from both legume hosts and their rhizobial partners. HmuS is a heme degrading factor widely distributed in bacteria, but little is known about the role of rhizobial <jats:italic>hmuS</jats:italic> in symbiosis with legumes. Here, we found that inactivation of <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> in the symbiotic plasmid of <jats:italic>Mesorhizobium amorphae</jats:italic> CCNWGS0123 disrupted rhizobial infection, primordium formation, and nitrogen fixation in symbiosis with <jats:italic>Robinia pseudoacacia</jats:italic>. Although there was no difference in bacteroids differentiation, infected plant cells were shrunken and bacteroids were disintegrated in nodules of plants infected by the Δ<jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> mutant strain. The balance of defence reaction was also impaired in Δ<jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> strain‐infected root nodules. <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> was strongly expressed in the nitrogen‐fixation zone of mature nodules. Furthermore, the HmuS<jats:sub>pSym</jats:sub> protein could bind to heme but not degrade it. Inactivation of <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> led to significantly decreased expression levels of oxygen‐sensing related genes in nodules. In summary, <jats:italic>hmuS</jats:italic><jats:sub>pSym</jats:sub> of <jats:italic>M. amorphae</jats:italic> CCNWGS0123 plays an essential role in nodule development and maintenance of bacteroid survival within <jats:italic>R. pseudoacacia</jats:italic> cells, possibly through heme‐binding in symbiosis.</jats:p>","is_dataset_classified":null,"base_score":1.6094379124341003,"endowment":1.6094379124341003,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"35419804","pmcid":null,"openalex_id":"https://openalex.org/W4223964136","authors":[],"funders":[{"funder_name":"National Natural Science Foundation of China","grant_id":"41830755","title":null},{"funder_name":"National Natural Science Foundation of China","grant_id":"42177329","title":null}],"total_grants":2,"fwci":0.5828,"citation_percentile":0.73345879,"influential_citations":0,"citation_trend":[{"year":2024,"count":1},{"year":2025,"count":2},{"year":2026,"count":1}],"oa_status":"closed","license":"http://onlinelibrary.wiley.com/termsAndConditions#vor","oa_locations":[{"url":"https://onlinelibrary.wiley.com/doi/pdf/10.1111/pce.14335","host_type":"publisher"},{"url":"https://onlinelibrary.wiley.com/doi/full-xml/10.1111/pce.14335","host_type":"publisher"},{"url":"https://doi.org/10.1111/pce.14335","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/35419804","host_type":"repository"}],"fields_of_study":["Legume Nitrogen Fixing Symbiosis","Coastal wetland ecosystem dynamics","Plant nutrient uptake and metabolism"],"mesh_terms":["Fibrinogen","Heme","Fabaceae","Nitrogen","Nitrogen Fixation","Rhizobium","Symbiosis","Robinia","Root Nodules, Plant","Mesorhizobium"],"keywords":["Rhizobia","Symbiosis","Nitrogen fixation","Biology","Mesorhizobium","Heme","Root nodule","Robinia","Rhizobium","Nitrogenase","Rhizobiaceae","Mutant","Leghemoglobin","Nod factor","Microbiology","Botany","Biochemistry","Bacteria","Genetics","Gene","Legume Symbiosis","Rhizobial Infection","Immune Homoeostasis","Bacteroid Survival"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Life in Land"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-07-28T11:08:05.705489Z","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":[]}