International Journal of Agricultural Policy and Research
Vol.2 (12), pp. 460-467, December 2014
Article 14/ID/JPR213/08/ pages
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License.
Original Research Article
Bacteria associated with different legume species grown in heavy-metal contaminated soils
Imen C. Fatnassi,Manel Chiboub, Moez Jebara* and Salwa H. Jebara
Laboratory of Legumes, Centre of Biotechnology of Borj Cedria, Hammam Lif 2050, BP901. University Tunis El Manar. Tunisia.
*Corresponding Author E-mail : moez.jebara(at)mes.rnu.tn
Tel.: (+216) 22583307;
Fax: (+216) 79325948
This study was conducted on seven experimental soil samples from mining and agricultural sites in Tunisia. Four local legumes, Vicia faba, Lens culinaris, Cicer arietinum and Sulla coronaria, were tested to select appropriate legume–tolerant bacteria symbionts for specific metal contamination. Soil analysis showed that Cd, Pb, Zn and Cu concentrations were significantly higher in contaminated sites than in agricultural soils. Investigation of legumes response to contamination showed that the greatest reduction in the shoot and root dry weights was observed in Sulla coronaria upon Cd contamination due to highly metal accumulation; while Vicia faba and Lens culinaris contained Cu and Pb respectively in their organs. Metal tolerance analyses showed that isolates from Vicia faba could grow with maximum Cu, Pb and Cd levels of 2, 4 and 4.5 mM, respectively; however, isolates from the others tested legumes were more sensitive to heavy metals. Genetic characterization by PCR-RFLP of the 16S rDNA for 20% of the isolates revealed different species including Rhizobium leguminosarum, Rhizobium phaseolus, Rhizobium etli and Agrobacterium. Selected Rhizobium species were chosen with their appropriate legumes to form prospective symbiotic systems for eventual phytostabilisation purposes, which should be tested in contaminated areas.
Key words: Heavy metals, legumes, Rhizobacteria, Soil, Symbioses