Role of sulfate and S-rich compounds in heavy metal tolerance and accumulation

Plants can withstand the potentially toxic effects exerted by a number of heavy metals through exclusion, which consists in restricted metal transport into plant tissues, or accumulation of metals, accompanied by the development of concomitant internal tolerance mechanisms. Plant tolerance and accumulation to heavy metals are known to be related to sulfur assimilation. The presence of metals can differently modulate genes involved in sulfate uptake and induce the sulfate assimilatory pathway. The regulation of S assimilation may be necessary to ensure an adequate supply of sulfur compounds requiredd for heavy metal detoxification. The individuation of limiting steps of the sulfate assimilatory pathway in heavy metal tolerance and accumulation allows the possibility of genetic engineering approaches in order to develop plants with augmented phytoremediation capacity