Antioxidant helps plants survive in toxic metallic environments, study shows
- Staff writers
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- David Salt, at right, a Purdue University professor of horticulture, and doctoral student John Freeman are finding out why certain plants thrive while others wither when exposed to massive amounts of nickel.
- Their findings provide insight for the development of plants that can remove toxic metals from polluted sites or extract useful metals from soil, a process known as phytomining.
- This finding, published in the current issue of The Plant Cell, provides an important new insight for the development of plants that could be used to help clean polluted sites.
- The work also answers a fundamental question for researchers studying how certain types of plants tolerate levels of metals in their tissues that are toxic to most other plants.
- "We were able to clearly establish for the first time that plants that create and accumulate high cellular levels of the antioxidant glutathione are much more nickel tolerant," said David Salt, associate professor of plant molecular physiology in Purdue''s horticulture department.
- The term antioxidant generally refers to a broad class of compounds that protect cells from damage otherwise caused by exposure to certain highly reactive compounds.
- "One major hurdle to developing hyperaccumulating plants is toxicity," said John Freeman, first author of the paper and a doctoral student working with Salt.
- "For a plant to hyperaccumulate metal, it has to be able to tolerate metal toxicity."
- A nearly ubiquitous antioxidant, glutathione plays a critical role in minimizing oxidative stress, or damage caused by highly reactive compounds, Salt said.
- Plants require metals like nickel in minute quantities for certain metabolic processes, but at high levels metals can damage membranes, DNA and other cell components.
- In this study, Salt and his colleagues sampled a number of closely related plants that grow on soils naturally enriched in nickel.
- He and his colleagues isolated a gene called SAT, and inserted it into a model lab plant called Arabidopsis thaliana, which does not normally tolerate nickel.