Evaluation of different Fusarium species–wheat interactions effect on Cd biosorption by wheat seedlings

Cadmium as common inorganic toxicants is strongly phytotoxic, and its uptake has been well documented. In the present study, the ability of isolated fungal strains toward remediation of cadmium was studied through minimum inhibition concentration. Ninety-two Cadmuim tolerant fungal strains belong to different species were isolated from some contaminated site in Isfahan/Iran. Among different isolated fungi, Fusarium species were selected for further analysis. The majority of the isolates were able to tolerate up to 250 ppm concentration of Cd. In addition, cadmium biosorption of inoculated and non-inoculated wheat with Fusarium species was measured in the laboratory experiments to determine the role of fungal partner in heavy metal biosorption by plants. Fungal cadmium adsorption conformed to the dry weight of fungal biomass. Among these isolates F. oxysporum, F. circinatum and some Fusarium sp. were found to be most significant in reducing Cd content, respectively, in the liquid media. Fusarium oxysporum exhibited the maximum fungal mass dry weight/Cd concentration (ppm) of 652/43 at 100 ppm of Cd. Pathogenicity tests were performed to determine the kind of Fusarium species parasitism behavior. The interaction between different Fusarium species and wheat seedlings was evaluated and reflected the higher uptake of Cd by wheat plants in interaction with some pathogenic Fusarium species but not all of them. Endophytic F. oxysporum showed a significant reduction in Cd absorption in wheat in comparison with the control. This indicated the potential of this isolate as biosorbent for removal of Cd and seeds inoculation for more efficient and practical purpose.