Use of gaseous 13NH3 administered to intact leaves of Nicotiana tabacum to study changes in nitrogen utilization during defence induction |
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Authors: | NILS HANIK SARA GÓMEZ MICHAEL SCHUELLER COLIN M ORIANS RICHARD A FERRIERI |
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Institution: | 1. Fachbereich Chemie, Johannes Gutenberg Universit?t, 55099 Mainz, Germany;2. Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA;3. Brookhaven National Laboratory, Medical Department, Upton, NY 11973, USA;4. Tufts University, Department of Biology, Medford, MA 02155, USA |
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Abstract: | Nitrogen‐13 (t1/2 9.97 m), a radioactive isotope of nitrogen, offers unique opportunities to explore plant nitrogen utilization over short time periods. Here we describe a method for administering 13N as gaseous 13NH3 to intact leaves of Nicotiana tabacum L. (cv Samsun), and measuring the labelled amino acids using radio high‐performance liquid chromatography (HPLC) on tissue extract. We used this method to study the effects of defence induction on plant nitrogen utilization by applying treatments of methyl jasmonate (MeJA), a potent defence elicitor. MeJA caused a significant increase relative to controls in key 13N]amino acids, including serine, glycine and alanine by 4 h post‐treatment, yet had no effect on 13NH3 incorporation, a process that is primarily under the control of the glutamine synthatase/glutamate synthase pathway (GS/GOGAT) in cellular photorespiration. We suggest that the reconfiguration of nitrogen metabolism may reflect induction of non‐photorespiratory sources of nitrogen to better serve the plant's defences. |
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Keywords: | amino acid synthesis methyl jasmonate plant defences short‐lived radiotracers |
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