title: Burkholderia novacaledonica sp. nov. and B. ultramafica sp. nov. isolated from roots of Costularia spp. pioneer plants of ultramafic soils in New Caledonia.
abstract: The taxonomic status of eleven rhizospheric bacterial strains belonging to the genus Burkholderia and isolated from roots of Costularia (Cyperaceae), tropical herbaceous pioneer plants growing on ultramafic soils in New Caledonia, was investigated using a polyphasic taxonomic approach. The genetic analyses (16S rRNA genes, gyrB, recA, nreB and cnr) confirmed that all strains are Burkholderia and cluster into two separated groups. The DNA hybridization results showed low relatedness values to the closest relatives Burkholderia species. The phenotypic analyses confirmed that the two groups of strains could be differentiated from each other and from other known Burkholderia species. This polyphasic study revealed that these two groups of strains represent each a novel species of Burkholderia, for which the names Burkholderia novacaledonica sp. nov. (type strain STM10272(T)=LMG28615(T)=CIP110887(T)) and B. ultramafica sp. nov. (type strain STM10279(T)=LMG28614(T)=CIP110886(T)) are proposed, respectively. These strains of Burkholderia presented specific ecological traits such as the tolerance to the extreme edaphic constraints of ultramafic soils: they grew at pH between 4 and 8 and tolerate the strong unbalanced Ca/Mg ratio (1/19) and the high concentrations of heavy metals i.e. Co, Cr, Mn and Ni. Noteworthy B. ultramafica tolerated nickel until 10mM and B. novacaledonica up to 5mM. The presence of the nickel (nreB) and cobalt/nickel (cnr) resistance determinants encoding for protein involved in metal tolerance was found in all strains of both groups. Moreover, most of the strains were able to produce plant growth promoting molecules (ACC, IAA, NH3 and siderophores). Such ecological traits suggest that these new species of Burkholderia might be environmentally adaptable plant-associated bacteria and beneficial to plants.
authors.affiliation: Université de la Nouvelle-Calédonie, Laboratoire Insulaire du Vivant et de l'Environnement, BPR4, 98851 Nouméa Cedex, Nouvelle-Calédonie, France; Université de Toulon, Laboratoire MAPIEM EA 4323, SeaTech-Ecole d'ingénieurs, BP 20132, 83957 La Garde Cedex, France. Electronic address: linda.guentas@univ-nc.nc.
authors.forename: Linda
authors.initials: L
authors.lastname: Guentas
authors.affiliation: Université de la Nouvelle-Calédonie, Laboratoire Insulaire du Vivant et de l'Environnement, BPR4, 98851 Nouméa Cedex, Nouvelle-Calédonie, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Gensous
authors.affiliation: Université de la Nouvelle-Calédonie, Laboratoire Insulaire du Vivant et de l'Environnement, BPR4, 98851 Nouméa Cedex, Nouvelle-Calédonie, France.
authors.forename: Yvon
authors.initials: Y
authors.lastname: Cavaloc
authors.affiliation: CIRAD, Laboratoire des Symbioses Tropicales et Méditerranéennes, LSTM UMR 082 Campus International de Baillarguet, TA-A82/J, 34398 Montpellier cedex 5, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Ducousso
authors.affiliation: Université de la Nouvelle-Calédonie, Laboratoire Insulaire du Vivant et de l'Environnement, BPR4, 98851 Nouméa Cedex, Nouvelle-Calédonie, France.
authors.forename: Hamid
authors.initials: H
authors.lastname: Amir
authors.affiliation: Institut Pasteur de Nouvelle-Calédonie, 9-11 avenue Paul Doumer - BP 61, 98845 Nouméa Cedex, Nouvelle-Calédonie, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: De Georges de Ledenon
authors.affiliation: IRD, UMR IMPE, 911, avenue Agropolis BP 64501, 34394 Montpellier cedex 5, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Moulin
authors.affiliation: IRD, UMR IMPE, 911, avenue Agropolis BP 64501, 34394 Montpellier cedex 5, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Jourand
mesh_terms: D015373:Bacterial Typing Techniques; D001482:Base Composition; D001483:Base Sequence; D019117:Burkholderia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D029785:Cyperaceae / Q000382:microbiology*; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D019216:Metals, Heavy / Q000378:metabolism*; D009510:New Caledonia; D018517:Plant Roots / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics; D017422:Sequence Analysis, DNA; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D019216:Metals, Heavy; D012336:RNA, Ribosomal, 16S; D012987:Soil; D011938:Rec A Recombinases; D027081:DNA Gyrase
keywords: Burkholderia novacaledonica; Burkholderia ultramafica; Costularia; New Caledonia; Ultramafic soils