title: Characterization of efficient plant-growth-promoting bacteria isolated from Sulla coronaria resistant to cadmium and to other heavy metals.
abstract: The inoculation of plants with plant-growth-promoting rhizobacteria has become a priority in the phytoremediation of heavy-metal-contaminated soils. A total of 82 bacteria were isolated from Sulla coronaria root nodules cultivated on four soil samples differently contaminated by heavy metals. The phenotypic characterization of these isolates demonstrated an increased tolerance to cadmium reaching 4.1mM, and to other metals, including Zn, Cu and Ni. Polymerase Chain Reaction/Restriction Fragment Length Polymorphism (PCR/RFLP) analysis showed a large diversity represented by genera related to Agrobacterium sp., R. leguminosarum, Sinorhizobium sp., Pseudomonas sp., and Rhizobium sp. Their symbiotic effectiveness was evaluated by nodulation tests. Taking into consideration efficiency and cadmium tolerance, four isolates were chosen; their 16SrRNA gene sequence showed that they belonged to Pseudomonas sp. and the Rhizobium sullae. The selected consortium of soil bacteria had the ability to produce plant-growth-promoting substances such as indole acetic acid and siderophore. The intracellular Cd accumulation was enhanced by increasing the time of incubation of the four soil bacteria cultivated in a medium supplemented with 0.1mM Cd. The existence of a cadmium-resistant gene was confirmed by PCR. These results suggested that Sulla coronaria in symbiosis with the consortium of plant-growth-promoting rhizobacteria (PGPR) could be useful in the phytoremediation of cadmium-contaminated soils.
authors: Laboratoire des légumineuses, centre de biotechnologie Borj Cedria, university Tunis El Manar, BP 901, 2050 Hammam Lif, Tunisia.
authors: Manel
authors: M
authors: Chiboub
authors: Laboratoire des légumineuses, centre de biotechnologie Borj Cedria, university Tunis El Manar, BP 901, 2050 Hammam Lif, Tunisia.
authors: Omar
authors: O
authors: Saadani
authors: Laboratoire des légumineuses, centre de biotechnologie Borj Cedria, university Tunis El Manar, BP 901, 2050 Hammam Lif, Tunisia.
authors: Imen Challougui
authors: IC
authors: Fatnassi
authors: Laboratoire des légumineuses, centre de biotechnologie Borj Cedria, university Tunis El Manar, BP 901, 2050 Hammam Lif, Tunisia.
authors: Souhir
authors: S
authors: Abdelkrim
authors: Laboratoire des légumineuses, centre de biotechnologie Borj Cedria, university Tunis El Manar, BP 901, 2050 Hammam Lif, Tunisia.
authors: Ghassen
authors: G
authors: Abid
authors: Laboratoire des légumineuses, centre de biotechnologie Borj Cedria, university Tunis El Manar, BP 901, 2050 Hammam Lif, Tunisia.
authors: Moez
authors: M
authors: Jebara
authors: Laboratoire des légumineuses, centre de biotechnologie Borj Cedria, university Tunis El Manar, BP 901, 2050 Hammam Lif, Tunisia. Electronic address: jebarasalwa@yahoo.fr.
authors: Salwa Harzalli
authors: SH
authors: Jebara
mesh_terms: D060054:Agrobacterium / Q000235:genetics; D001419:Bacteria / Q000737:chemistry*; D001673:Biodegradation, Environmental; D044822:Biodiversity; D002104:Cadmium / Q000633:toxicity*; D007887:Fabaceae / Q000254:growth & development* / Q000382:microbiology*; D014644:Genetic Variation; D019216:Metals, Heavy / Q000633:toxicity*; D055170:Plant Root Nodulation / Q000235:genetics; D018517:Plant Roots / Q000382:microbiology; D011549:Pseudomonas / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012231:Rhizobium / Q000235:genetics; D020579:Sinorhizobium / Q000235:genetics; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*; D013559:Symbiosis
chemical_list: D019216:Metals, Heavy; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D002104:Cadmium
keywords: Cadmium; Heavy metal; PGPR; Sulla coronaria; Symbiosis