title: Culturable endophytic bacteria enhance Ni translocation in the hyperaccumulator Noccaea caerulescens.
abstract: In this work, both culture-dependent and independent approaches were used to identify and isolate endophytic bacteria from roots of the Ni hyperaccumulator Noccaea caerulescens. A total of 17 isolates were cultured from root samples, selected for tolerance to 6mM Ni and grouped by restriction analysis of 16S rDNA. Bacterial species cultivated from roots belonged to seven genera, Microbacterium, Arthrobacter, Agreia, Bacillus, Sthenotrophomonas, Kocuria and Variovorax. The culture-independent approach confirmed the presence of Microbacterium and Arthrobacter while only other five clones corresponding to different amplified ribosomal DNA restriction patterns were detected. Five selected highly Ni-resistant bacteria showing also plant growth promoting activities, were inoculated into seeds of N. caerulescens, and in vivo microscopic analysis showed rapid root colonisation. Inoculated plants showed increased shoot biomass, root length and root-to-shoot Ni translocation. Root colonisation was also evident, but not effective, in the non-hyperaccumulating Thlaspi perfoliatum. Seed inoculation with selected Ni-resistant endophytic bacteria may represent a powerful tool in phytotechnologies, although transferring it to biomass species still requires further studies and screening.
authors.affiliation: Department of Life Sciences, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy. Electronic address: giovanna.visioli@unipr.it.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Visioli
authors.affiliation: Department of Life Sciences, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: D'Egidio
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and the Environment, University of Padova, Viale dell' Università 16, 35020 Legnaro-Padova, Italy.
authors.forename: Teofilo
authors.initials: T
authors.lastname: Vamerali
authors.affiliation: Department of Chemistry, University of Parma, Parco Area delle Scienze 17/A, Parma, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Mattarozzi
authors.affiliation: Department of Life Sciences, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Sanangelantoni
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D019607:Brassicaceae / Q000378:metabolism* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D060026:Endophytes / Q000145:classification / Q000378:metabolism*; D007558:Italy; D008969:Molecular Sequence Data; D009532:Nickel / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012989:Soil Pollutants / Q000378:metabolism*; D031227:Thlaspi / Q000378:metabolism / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D009532:Nickel
keywords: Heavy metal-resistant endophytes; Ni accumulation; Noccaea caerulescens; Serpentine soils