Comprehensive chemical profiling of gramineous plant root exudates using high-resolution NMR and MS

被引:129
作者
Fan, TWM
Lane, AN
Shenker, M
Bartley, JP
Crowley, D
Higashi, RM
机构
[1] Univ Calif Davis, Dept Land Air & Water Resources, Davis, CA 95616 USA
[2] Natl Inst Med Res, Div Mol Struct, London NW7 1AA, England
[3] Hebrew Univ Jerusalem, Fac Agr Food & Environm Qual Sci, Dept Soil & Water Sci, IL-76100 Rehovot, Israel
[4] Queensland Univ Technol, Sch Phys Sci, Brisbane, Qld 4001, Australia
[5] Univ Calif Riverside, Dept Soil & Environm Sci, Riverside, CA 92521 USA
[6] Univ Calif Davis, Crocker Nucl Lab, Davis, CA 95616 USA
关键词
Hordeum vulgare; Triticum aestivum; gramineae; multinuclear and 2-D NMR spectroscopy; high-resolution MS; Fe deficiency; metal sequestration; metal ion ligands; cadmium; phytosiderophores; mugineic acids;
D O I
10.1016/S0031-9422(01)00007-3
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Root exudates released into soil have important functions in mobilizing metal micronutrients and for causing selective enrich ment of plant beneficial soil micro-organisms that colonize the rhizosphere. Analysis of plant root exudates typically has involved chromatographic methods that rely on a priori knowledge of which compounds might be present. In the research reported here, the combination of multinuclear and 2-D NMR with GC-MS and high-resolution MS provided de novo identification of a number of components directly in crude root exudates of different plant types. This approach was applied to examine the role of exudate metal ion ligands (MIL) in the acquisition of Cd and transition metals by barley and wheat. The exudation of mugineic acids and malate was enhanced by Fe deficiency, which in turn led to an increase in the tissue content of Cu, Mn, and Zn. The presence of elevated Cd maintained at a free activity pCd of 8.8 (10-(8.8) M), resulted in reduced phytosiderophore production by Fe deficient plants. The buffer morpholinoethane sulfonate (MES), which is commonly used in chelator-buffering nutrient solutions, was detected in the root exudate mixture, suggesting uptake and re-secretion of this compound by the roots. The ability to detect this compound in complex mixtures containing organic acids, amino acids, and other substances suggests that the analytical methods used here provide an unbiased method for simultaneous detection of all major components contained in root exudates. (C) 2001 Elsevier Science Ltd. All rights reserved.
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页码:209 / 221
页数:13
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