期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2007
卷号：104
期号：43
页码：16964-16969
DOI：10.1073/pnas.0707198104
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Fine fescue grasses displace neighboring plants by depositing large quantities of an aqueous phytotoxic root exudate in the soil rhizosphere. Via activity-guided fractionation, we have isolated and identified the nonprotein amino acid m-tyrosine as the major active component. m-Tyrosine is significantly more phytotoxic than its structural isomers o- and p-tyrosine. We show that m-tyrosine exposure results in growth inhibition for a wide range of plant species and propose that the release of this nonprotein amino acid interferes with root development of competing plants. Acid hydrolysis of total root protein from Arabidopsis thaliana showed incorporation of m-tyrosine, suggesting this as a possible mechanism of phytotoxicity. m-Tyrosine inhibition of A. thaliana root growth is counteracted by exogenous addition of protein amino acids, with phenylalanine having the most significant effect. The discovery of m-tyrosine, as well as a further understanding of its mode(s) of action, could lead to the development of biorational approaches to weed control.
