Cadmium and lead resistant rhizospheric bacteria as candidates for rhizoremediation processess

SARAN, A; FERNANDEZ, L; MASSOT, F; MERINI, LJ

Córdoba

Congreso; 52 Annual Meeting - Argentine Society for Biochemistry and Molecular Biology; 2016

SAIB

Although Helianthus petiolaris has been identified as a cadmium and lead tolerant plant species, little is known about its rhizospheric microorganisms. Such microorganisms are crucial for enhancing the plant biomass production and tolerance to heavy metals, accelerating the phytoremediation process of contaminated soils. The aim of this work was to isolate and identify the cadmium and lead tolerant rhizospheric bacteria from H. petiolaris and assess its plant growth-promoting (PGPR) capabilities. Bacteria isolation was performed by washing the roots with saline and saline/Tween 80 solutions, which were inoculated into sterile GY media supplemented with either 10 mg L-1Cd+2 or 100 mg L-1Pb+2. After several rounds of enrichment culture in the GY/metal medium and subsequent purification by plate culture, nine different morphotypes were isolated. From biochemical analysis and 16S rRNA sequencing, the lead resistant bacteria were identified as Bacillus subtilis, Klebsiella pneumoniae, Klebsiella oxytoca and Rhodococcus equi. Identification of cadmium tolerant strains is in progress. In addition plant growth promotion capabilities, such as phosphate solubilization, phytohormones production (AIA), nitrogen fixation and siderophore production, were determined for the strains.