Use of gaseous 13NH3 administered to intact leaves of Nicotiana tabacum to study changes in nitrogen utilization during defence induction.
Nitrogen-13 (t(1/2) 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 (13)N as gaseous (13)NH(3) 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 [(13)N]amino acids, including serine, glycine and alanine by 4 h post-treatment, yet had no effect on (13)NH(3) 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.
Hanik
Nils
N
Fachbereich Chemie, Johannes Gutenberg Universität, Mainz, Germany.
Gómez
Sara
S
Schueller
Michael
M
Orians
Colin M
CM
Ferrieri
Richard A
RA
D000085:Acetates / Q000378:metabolism*; D000596:Amino Acids / Q000096:biosynthesis; D000641:Ammonia / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000008:administration & dosage / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D013312:Stress, Physiological; D014026:Nicotiana / Q000378:metabolism*
D000085:Acetates; D000596:Amino Acids; D003517:Cyclopentanes; D009587:Nitrogen Isotopes; D054883:Oxylipins; D002245:Carbon Dioxide; D000641:Ammonia; C072239:methyl jasmonate; D009584:Nitrogen