Simultaneous efflux and uptake of metabolites by roots of wheat
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Background & aims
Some metabolites (e.g. amino acids) present in root exudates can be taken up by roots, but we do not know if this ability extends to the broader suite of metabolites found in exudates. The aim of this study was to examine the ability of wheat (Triticum aestivum L.) to efflux and take up a broad suite of small metabolites.
Four-week-old plants were placed into an uptake solution that contained a broad suite of 13C-labelled metabolites. Uptake was estimated from the decrease in concentration of the 13C isotopologue in the solution; and from the appearance of 13C isotopologues within roots. Efflux was estimated from appearance of 12C isotopologues in solution.
When wheat plants were placed in 13C-metabolite solutions the concentration of U-13C isotopologues of 37 metabolites decreased – as would be expected if plants were taking up the U-13C metabolites. After 4 h immersion in 13C metabolite solution, roots contained detectable amounts of U-13C isotopologues of 55 metabolites. U-13C isotopologues of organic acids were not detected within roots.
These findings indicate that wheat can take up a broad suite of N-containing metabolites and some sugars, but there was no evidence for uptake of organic acids.
KeywordsEfflux Uptake Root Mass spectrometry Stable isotope Metabolite
Charles Warren was supported by a Future Fellowship from the Australian Research Council. The University of Sydney is thanked for financial support via the major equipment scheme.
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