Metallothioneins and Metal Ion Transporters in Phragmites: Possibilities for Phytoremediation

Nichole Walker (‘11) and Yourha Kang, Theta Xi Chapter, Beta Beta Beta

Department of Biology, Iona College 715 North Avenue New Rochelle, NY 10801

Abstract:

Phragmites australis, also known as the common reed, is a wetland grass found throughout the contiguous United States and is considered to be an invasive species, where the European variety has out-competed native plant species in many habitats forming a monoculture of Phragmites over large areas of land. One of the reasons for its success is that the species is able to survive in a number of wetland habitats polluted with various contaminants, including relatively high amounts of heavy metal ions like iron, lead, and copper. Due to Phragmites’ survivability in such environments, it has been suggested that Phragmites be used in phytoremediation, where plants are used to remove inorganic pollutants, like heavy metals, from the environment. Metallothioneins and metal ion transporters function in the uptake, translocation, and compartmentalization of metals. This project aims to identify the roles of these proteins to allow for survival of plants, such as P. australis, in highly polluted, metal-enriched habitats. We have begun a search for genes that code for metallothionein and metal ion transporters. In order to do this, degenerate primers were derived from sequences of metallothioneins and well as iron, copper, and zinc transporters from related species. The primers were used in polymerase chain reactions to amplify putative DNA sequences whose products could be involved in heavy metal tolerance in Phragmites. Thus far, we amplified DNA sequences using metallothionein primers and copper primers. Those from metallothionein primers were not similar to any known metallothionein genes. We are currently in the process of determining the sequences amplified from primers derived from copper transporters. Results will be presented and discussed.