| Abstract Detail
Environmental Physiology Schroeder, Peter [1], Scheer, Christian [2], Diekmann, Frauke [3], Stampfl, Andreas [4]. How plants cope with organic xenobiotics: Metabolism and transport of xenobiotic conjugates in the rhizosphere. Agricultural plants encounter foreign compounds via the atmosphere, in aqueous solution or as particles. They might be exposed by chance, or in the frame of agricultural activities towards these compounds. Resistance to herbicides has evolved in numerous species by induction of potent detoxification mechanisms. These mechanisms include the production of potent scavenger molecules like ascorbate or glutathione, but also the expression of defence enzymes, like the P450, glucosyl transferase and glutathione transferase superfamilies. In analogy to mammals, the resulting detoxification network has been named „green liver“. Herbicide resistance in plants is to a good part based on the availability of these metabolites and the presence of the respective enzymes.
It is generally accepted that plants build up soluble or bound residues after detoxification, i.e. from phase II products. Main storage pools are thought to be the central vacuoles and the cell walls of plant leaves. However, glutathione dependent detoxification leads to the formation of conjugates that remain soluble and are cleaved to form numerous products. These reactions are partially catalyzed in the cytosol, but also in the vacuoles. We demonstrate a long range transport of conjugates from barley leaves into roots. In contrast to glutathione conjugates, cysteine conjugates are transported at lower rates, which is indicative of the presence of specific transporters. It is of great interest for food safety considerations to know whether the resulting metabolites remain soluble and whether they might exert some effects on the plant or other organisms. Especially their potential escape into the rhizosphere might lead to alterations in the microbial life around plant roots. Studies are underway to elucidate the possible impact of xenobiotic metabolites on rhizosphere bacteria.
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1 - GSF national Research Center for Environment and Health, Microbe Plant Interactions, Ingolstädter Landstrasse 1, Neuherberg, Bavaria, D-85764, Germany
2 - University of Greenwich at Medway, School of Science
3 - GSF National Research Center for Environment and Health, Microbe Plant Interactions
4 - GSF National Research Center for Environment and Health, Institute for Toxicology
Keywords:
organic xenobiotic
glutathione S-transferases
Hordeum vulgare
peptide transport.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P01051
Abstract ID:2537 |
