ABSTRACT
Of the major groups of soil organisms, fungi have fundamental roles in nutrient decomposition, animal and plant pathogenesis and symbiosis, and element cycling, as well as a role in maintenance of soil structure due to their filamentous branching growth habit and frequent exopolymer production. It seems obvious that toxic metals and other pollutants will adversely affect soil properties if pollutant concentration and speciation result in mycotoxicity. Like other microorganisms, fungi possess a variety of properties that can influence interactions with metals, while normal growth and metabolism are also dependent on metal and metal-mineral interactions to satisfy trace metal and associated nutrient requirements. Nevertheless, at potentially toxic metal concentrations, a variety of resistance mechanisms may be expressed: sensitive organisms may be vulnerable to toxic symptoms, resulting in population changes. However, metal toxicity can be greatly influenced by the physicochemical attributes of the soil environment, while fungi possess a variety of intrinsic properties that can ensure survival. It seems fungi can be isolated from any soil polluted by toxic metals. This chapter outlines the effects toxic metals may have on fungal communities, the physiogical and morphological strategies employed to combat metal stress, mechanisms of resistance, fungal-mediated metal transformations, and the role of fungi in the geochemistry of metal cycling, as well the applied significance of these processes in environmental biotechnology.
