The potential role of plant-associated bacteria in metal uptake and metal translocation in Nicotiana tabacum

Abstract

It is known that rhizospheric and endophytic bacteria may carry out a variety of functions improving plant growth (Mastretta et al., 2007). In agriculture they are under investigation as an alternative for chemical fertilizers to improve plant yield. These bacteria can also improve the nutrient status of their host plant due to biological nitrogen fixation (diazotrophy) and increasing nutrient availability into the rhizosphere through solubilization of minerals. Plant biomass production can also be increased via the synthesis of plant hormones by the bacteria. Plantassociated bacteria further seem to be able to reduce or prevent the deleterious effects of phytopathogenic organisms through competition, antibiosis and Induced Systemic Resistance (ISR) in plants. During recent years, their ubiquitous existence combined with the large variability of metabolic functions that they may carry out, attracted attention for their potential to improve phytoremediation. This thesis aims to improve our understanding of the potential contribution of plant-associated bacteria, which naturally occur in Nicotiana tabacum grown on soils with increased metal contents, to improve metal uptake and translocation in their host plant. We compared the endophytic consortia associated with tobacco plants growing on two metal contaminated sites....