Plant Genes that Remedy Arsenic Poisoning (2010.11.17)
Arsenic is a poisonous metalloid that pollutes the land and drinking water in many countries in Southeast Asia, mainly in Bangladesh or Cambodia, and neither is a developed country free from this problem: it still remains in certain mining areas, timber or paper mills and industrial areas. The ingestion of crops contaminated by arsenic can cause cancer, digestive disorders and skin diseases, because it becomes accumulated in the human body instead of being digested or excreted.
Professor Youngsook Lee, Department of Life Science, and her research team including Dr. Won-Yong Song, Postdoctoral Fellow, and Ms. Jiyoung Park, PhD candidate, has discovered two plant genes that can remedy the poisonous element, arsenic. This achievement not only contributes to solving the problem of environmental arsenic poisoning, but also presents the possibility of developing crops that absorb less arsenic even if planted in contaminated soil.
Named AtABCC1 and AtABCC2, these genes protect the plant from toxic arsenic through compartmentalization of arsenic conjugated by phytochelatin into vacuole, which can play important roles in plant defense as a final store for toxic elements. This is the first time that the existence of such genes that sequester toxic metal/metalloid chelated by phytochelatin into the vacuole is revealed in a plant, although the role of phytochelatin has been known for 50 years as a plant chelator to detoxify poisonous properties of heavy metals or metalloids.
The key point behind this achievement was the team’s discovery that mutant plants without the genes AtABCC1 and AtABCC2 are very sensitive to arsenic and very ineffective in transporting the arsenic conjugated with phytochelatin. The transgenic plants over-expressing AtABCC1 and the phytochelatin synthase gene developed by Professor Lee’s team showed enhanced growth compared to the wild type plants, which proves that if the two genes are put into appropriate use, a plant’s resistance against arsenic can be greatly improved.
Professor Lee remarked “this recent achievement is the result of 10 years’ work in our lab on the development of plants that can help remedy the environment,” and added that she “looks forward to contributing in making clean arsenic contaminated regions, which is currently a huge problem for people in Southeast Asia.”
The findings were published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS) by the National Academy of Science, USA, in 2010. Also, their paper received the Cozzarelli Prize, which is exclusively granted to the most exceptional papers. The research was under co-leadership of Professor Martinoia’s team at the University of Zurich, Switzerland, and involved Professor Schroeder’s team at the University of California, San Diego, USA. Also, Professor Lee’s project was supported by the Korean Ministry of Education and Science and by the Global Research Lab of the National Research Foundation of Korea.