Characterization of the molecular basis of arsenic tolerance and hyperaccumulation in gametophytes of the fern Pteris vittata

Elemental arsenic (As) is a ubiquitous and naturally occurring contaminant of soils and ground water in many regions of the world, including the United States. In most organisms, continuous exposure to arsenic may lead to chronic pathologies or death. Sporophytes and gametophytes of the fern Pteris vittata L. both tolerate and accumulate extraordinarily high levels of As. To date no other organism has been shown to accumulate arsenic to the levels observed in P. vittata. I have developed P. vittata gametophytes as a model system for identifying potential mechanisms that facilitate arsenic tolerance and accumulation in this unique plant. Here I will describe characterization of biochemical mechanisms utilized in the Pteris gametophyte for arsenic tolerance and hyperaccumulation. Furthermore the cloning and initial characterization of a unique arsenic reductase from this plant will be described.