{
  "id": 12938202,
  "title": "Characterization of two Martinezella spp. species: M. legmii sp. nov. and M. ivanii sp. nov., from tropical legume trees in Costa Rica",
  "url": "https://urgent.news/2026/10/08/characterization-of-two-martinezella-spp-species-m-legmii-sp-nov-and",
  "topic": "science",
  "section": "Science",
  "published": "2026-10-08T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.10.06.757023v1?rss=1"
  },
  "original_language": "en",
  "account": "Four rhizobial strains were discovered in root nodules of tropical leguminous plants in Costa Rica. LEGMi-135b came from Lonchocarpus felipei nodules, LEGMi-12c from Cojoba arborea, LEGMi-198b from Calliandra haematocephala, and Rhizobium altiplani LEGMi-166a from Mimosa pigra. Phylogenetic studies based on the 16S rRNA gene and four housekeeping genes placed these strains within Martinezella and Rhizobium, with LEGMi-135b, LEGMi-12c, and LEGMi-198b falling under Martinezella, and LEGMi-166a under Rhizobium. Genome comparison indicated that LEGMi-135b had 94% ANI and 53.2% dDDH with Martinezella hainanensis CCBAU 57015T, supporting its status as a distinct species. LEGMi-12c showed 98% ANI and 87% dDDH with Martinezella hainanensis CCBAU 57015T, while LEGMi-198b was most similar to Rhizobium cerradonense CNPSo 3464, with 98% ANI and 81.4% dDDH. LEGMi-166a was confirmed with 100% ANI and 99.3% dDDH with Rhizobium altiplani BR 10423, solidifying its classification in Rhizobium. The unique characteristics of LEGMi-135b and LEGMi-198b were further confirmed by their distinct phenotypic, physiological, and biochemical properties. Based on the comprehensive evidence, the study proposes the naming of two new rhizobial species: Martinezella legmii sp. nov., with LEGMi-135b as the type strain, and Martinezella ivanii sp. nov., with LEGMi-198b as the type strain. This research contributes to our knowledge of rhizobia associated with nitrogen-fixing symbiosis, particularly among Costa Rican tropical leguminous plants.",
  "summary": "Four rhizobial strains isolated from root nodules of tropical leguminous plants in Costa Rica were characterized. Strain LEGMi-135b was isolated from Lonchocarpus felipei root nodules, LEGMi-12c from Cojoba arborea, LEGMi-198b from Calliandra haematocephala and Rhizobium altiplani LEGMi-166a from Mimosa pigra. Phylogenetic analyses based on the 16S rRNA gene and four concatenated housekeeping…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}