Nitric oxide is involved in methyl jasmonate-induced defense responses and secondary metabolism activities of Taxus cells.
Methyl jasmonate (MeJA), a methyl ester of jasmonic acid (JA), is a well-established signal molecule in plant defense responses and an effective inducer of secondary metabolite accumulation in plant cell cultures such as the valuable anticancer diterpenoid taxol (paclitaxel) in Taxus spp. This work examines the involvement of nitric oxide (NO) in MeJA-induced plant defense responses and secondary metabolism in Taxus chinensis cell cultures. Exogenously supplied MeJA at 100 microM induced rapid production of NO in the Taxus cell cultures, reaching a maximum within 6 h of MeJA supply. Several other responses occurred concomitantly, including the production of hydrogen peroxide (H2O2), and the increases in intracellular malondialdehyde (MDA) content, lipoxygenase (LOX) and phenylalanine ammonium-lyase (PAL) activities. The MeJA-induced H2O2 production was suppressed by an NO donor, sodium nitroprusside (SNP), but enhanced by NO inhibitors, N (omega)-nitro-L-arginine (L-NNA) and 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (PTIO). In contrast, the MeJA-induced MDA, LOX and PAL were all enhanced by the NO donor but suppressed by the NO inhibitors. The NO inhibitors also suppressed MeJA-induced taxol accumulation. These results are suggestive of a role for NO as a signal element for activating the MeJA-induced defense responses and secondary metabolism activities of plant cells.
Wang
Jian Wen
JW
Department of Applied Biology & Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Wu
Jian Yong
JY
D000085:Acetates / Q000494:pharmacology*; D003497:Cyclic N-Oxides / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D008084:Lipoxygenase / Q000378:metabolism; D008954:Models, Biological; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019335:Nitroarginine / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D054883:Oxylipins; D017239:Paclitaxel / Q000096:biosynthesis; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D020946:Taxus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*
D000085:Acetates; D003497:Cyclic N-Oxides; D003517:Cyclopentanes; D016166:Free Radical Scavengers; D007093:Imidazoles; D020030:Nitric Oxide Donors; D054883:Oxylipins; D010937:Plant Growth Regulators; D009599:Nitroprusside; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D019335:Nitroarginine; D009569:Nitric Oxide; C072239:methyl jasmonate; D006861:Hydrogen Peroxide; D008084:Lipoxygenase; D010650:Phenylalanine Ammonia-Lyase; D017239:Paclitaxel