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Identification of effective Pb resistant bacteria isolated from Lens culinaris growing in lead contaminated soils
Author(s) -
Jebara Salwa Harzalli,
Abdelkerim Souhir,
Fatnassi Imen Challougui,
Chiboub Manel,
Saadani Omar,
Jebara Moez
Publication year - 2015
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201300874
Subject(s) - phytoremediation , apx , bacteria , shoot , pseudomonas , rhizobium , agrobacterium tumefaciens , superoxide dismutase , soil contamination , horticulture , soil water , peroxidase , chemistry , biology , inoculation , botany , symbiosis , food science , antioxidant , enzyme , biochemistry , transformation (genetics) , ecology , genetics , gene
Soil bacteria are a new phytoremediation system for the removal of heavy metals from soils. In this study, fifteen soil bacteria were isolated from root nodules of lentil growing in heavy metals contaminated soils, particularly by lead. Molecular characterization of the collection showed a large diversity, including Agrobacterium tumefaciens , Rahnella aquatilis , Pseudomonas , and Rhizobium sp. These soil bacteria had a wide range of tolerance to heavy metals. Among them, strains of A. tumefaciens and R. aquatilis tolerated up to 3.35 mM Pb; whereas Pseudomonas tolerated up to 3.24 mM Pb. The inoculation of lentil grown hydroponically with inoculums formed by these efficient and Pb resistant bacteria enhanced plant biomass. The treatment of this symbiosis by 1 mM Pb for 10 days or by 2 mM Pb for 3 days demonstrated that lentil had Pb accumulation capacity and can be considered a Pb accumulator plant, elsewhere, roots accumulated more Pb than shoots, and the inoculation decreased the Pb up take by the plants, suggesting that this symbiosis should be investigated for use in phytostabilization of Pb‐contaminated soils. At the same time, a modulation in the antioxidant enzyme activity and a specific duration was required for the induction of the superoxide dismutase (SOD), peroxidase (POX), and ascorbate peroxidase (APX) response and to adapt to Pb stress. These results suggested that these enzymes may be involved in the main mechanism of antioxidative defense in lentil exposed to Pb oxidative stress.