• Journal of Plant Biology
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• v.37 no.4
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• pp.445-452
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• 1994

Effects of methyl jasmonate (MeJA) on ethylene production in mungbean (Phaseolus radiatus L.) hypocotyl and leaf segments were studied. Ethylene production in mungbean hypocotyl segments was decreased in proportion to MeJA concentrations and $450\;\mu\textrm{M}$ of MeJA showed 50% inhibitory effect. This inhibitory effect appeared after 3 h of incubation period and continued for 24 h. Inhibition of ethylene production by MeJA was due to the decrease in 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase activity. However, MeJA treatment had no effect on ACC content and ACC synthase activity. MeJA also inhibited auxin-induced ethylene production in hypocotyls. To investigate the mechanisms of the inhibitory effect of MeJA on the auxin-induced ethylene production, ACC synthase and ACC oxidase activity were examined after MeJA treatment. MeJA decreased the ACC content and ACC synthase activity as weD as ACC oxidase activity in the auxin-treated tissue. These results suggest that the inhibition of MeJA on auxin-induced ethylene production is not due to the direct inhibitory effect of MeJA on the ACC synthase, but to the inhibition of the ability of IAA to promote the synthesis of ACC synthase. In contrast, ethylene production from the detached mungbean leaves was stimulated by MeJA. The rate of ethylene production increased approximately 65% over the control after 12 h of incubation period by $4.5\;\mu\textrm{M}$ MeJA. When MeJA was applied to detached leaves along with IAA, the effect of MeJA appeared to be additive. In an effort to elucidate mechanisms of MeJA action on auxin-induced ethylene production in the leaf tissue, enzyme activities of ACC synthase and ACC oxidase were examined. MeJA stimulated ACC oxidase activity but did not affect ACC synthase activity in leaf tissue. Together, these results suggest that MeJA plays different roles in the ethylene production in the different mungbean tissues.issues.

• Journal of Plant Biology
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• v.38 no.3
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• pp.235-242
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• 1995

Effects of methyl jasmonate (MeJA) on ethylene production in tomato(Lycopersicon esculentum Mill.) hypocotyl segments and fruits were studied. Ethylene production in tomato hypocotyl segments was inhibited by the increasing concentratons of MeJA, and 450 $\mu$M of MeJA showed 50% inhibitory effect. Time course data indicate that this inhibitory effect of MeJA appeared after 3 h of incubation period and continued until 24 h. Inhibition of ethylene producton by MeJA was due to the decrease in 1-aminocyclopropane-1-carboxylic acid(ACC) synthase activity. However, MeJA treatment had no effect on ACC oxidase activity and the accumulaton of ACC oxidase mRNAs. MeJA also inhibited auxin-induced ethylene production by decreasing in ACC synthase activity. In contrast, MeJA stimulated ethylene production in tomato fruits. When 30 $\mu$L/mL MeJA was treated in a gaseous state, ethylene production doubled and this stimulating effect continued until 4 days. To investigate the mechanisms of MeJA on ethylene production, ACC synthase and ACC oxidase activities were examined after MeJA treatment. MeJA increased the activities of both ACC synthase and ACC oxidase, and induced ACC oxidase mRNA accumulation. These data suggest that MeJA plays distinct roles in the ethylene production in different tomato tissues. It is possible that MeJA affects differently the mechanisms of signal transuction leading to the ethylene biosynthesis.

• Journal of Plant Biotechnology
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• v.2 no.2
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• pp.83-87
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• 2000

Carnation petals exhibit autocatalytic ethylene production and wilting during senescence. The autocatalytic ethylene production is induced by the expression of 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase genes, whereas the wilting of petals is related to expression of the cysteine proteinase (CP) gene. Until recently, it has been believed that these two phenomena, autocatalytic ethylene production and wilting, are regulated in concert in senescing carnation petals, since the two phenomena occurred closely in parallel. Our studies with petals of a transgenic carnation harboring a sense ACC oxidase transgene and petals of carnation flowers treated with 1,1-dimethyl-4-(phenylsulfonyl) semicarbazide showed that the expression of ACC synthase and ACC oxidase genes and that of CP are regulated differently in carnation psanetals. Interestingly, in the petals of transgenic carnation, the transcript for CP was accumulated but the transcripts for ACC synthase and ACC oxidase were not accumulated in response to exogenous ethylene. Based on these results, we hypothesized that two ethylene signaling pathways, one leading to the expression of ACC synthase and ACC oxidase genes and the other leading to the expression of CP gene, are functioning in senescing carnation petals.

• Journal of Plant Biology
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• v.39 no.1
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• pp.31-40
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• 1996

The physiological and biochemical characterizations of the ethylene-related mutants in Arabidopsis thaliana - ethylene overproducing mutant (eto1-l) and ethylene insensitive mutants (etrl-3, ein2-l) - were detailed in this studies. Two or three week.old mature rosette leaves (before bolting) were used as the plant materials. Ethylene productions of eto1-l, etrl-3, and ein2-l mutants were about 200%, 400%, and 450% compared to that of wild type, respectively. ACC synthase and ACC oxidase activities of eto1-l mutant were similar to those of wild type. ACC content and ACC N-malonyltransferase activity, however, were 4.5 times and 3 times higher than those of wild type, respectively. SAM synthetase activity increased by 50% in eto1-l mutant plant. These results indicated that the alteration in the eto1-l mutant occured before the step of the conversion of SAM to ACe. In etrl-3 and ein2-l mutants, ACC synthase activities increased, but ACC oxidase activities decreased. ACC content and ACC N-malonyltransfcrase activity were 2 times higher than those of wild type. SAM synthetase activity in etrl-3 is similar to those of wild type, while it increased by 73% in ein2-l. These results showed that the block in ethylene action affected the autoregulation of ethylene biosynthesis, so that ACC synthase activity was not autoinhibited and ACC oxidase activity was not auto stimulated by ethylene. When the leaf tissues were used for in vitro kinase assay, a cytosolic protein (approximately 36 kDa) was phosphorylated only in eto1-l and ein2-l mutants.utants.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.62.2-62.2
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• 2008

• Journal of Plant Biology
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• v.33 no.4
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• pp.309-314
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• 1990

Effect of mannose on auxin-induced ethylene production in corn (Zea mays L.) coleoptiles was studied. Auxin induced ethylene production decreased in proportion to mannose concentrations. The inhibitory effect of mannose appeared after 2 h of incubation. Ethylene production was significantly depressed by mannose at high concentration (10-5M-10-4M) of indole acetic acid (IAA), but not at low concentrations (10-8M-10-6M). The inhibition of auxin-induced ethylene production by mannose was specific, since other sugars such as galactose, glucose, sucrose and mannitol did not have an inhibitory effect. In an effort to elucidate mechanisms of mannose the effect on the auxin induced ethylene production, effect of the sugar on ACC synthase activity and ACC induced ethylene production was studied. Mannose failed to inhibit ACC mediated ethylene production, but decreased both the ACC content and ACC synthase activity in the tissue. These results suggest that the inhibitory effect of mannose on auxin induced ethylene production results from suppression of auxin induction of ACC synthase.

• Journal of Photoscience
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• v.10 no.2
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• pp.189-193
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• 2003

The effects of light on the regulation of ethylene biosynthesis during development of mung bean seedlings were investigated by monitoring the differential expression of seven 1-aminocyclopropane-l-carboxylate (ACC) synthase and two ACC oxidase genes. Among them, only the expression of VR-ACS1, VR-ACS6, VR-ACS7, VR-ACO1 and VR-AC02 was observable in etiolated mung bean hypocotyls. When the seedlings were de-etiolated for 1 d under a light/dark cycle of 16 h/8 h, the expression of VR-ACS6, VR-ACS7 and VR-ACO2 was controlled negatively by light. The expression of VR-ACS1 showed a tendency to increase until 6 h after a dark-to-light transition and then decreased at 12 h. On the other hand, the expression of VR-ACO1 was mostly constitutive up to 12 h after the dark-to-light transition. The opening of hypocotyl hooks during de-etiolation in the light was stimulated by the inhibition of the action of endogenous ethylene in the presence of 1-MCP. These results suggest that the negative regulation of light on the expression of ACC synthase and ACC oxidase genes eventually results in the inhibition of ethylene production with an acceleration of the opening of apical hooks.

• BMB Reports
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• v.38 no.3
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• pp.320-327
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• 2005

Five ripening-related ACC synthase cDNA isoforms were cloned from 80% ripe papaya cv. 'Sinta' by reverse transcription-PCR using gene-specific primers. Clone 2 had the longest transcript and contained all common exons and three alternative exons. Clones 3 and 4 contained common exons and one alternative exon each, while clone 1, the most common transcript, contained only the common exons. Clone 5 could be due to cloning artifacts and might not be a unique cDNA fragment. Thus, there are only four isoforms of ACC synthase mRNA. Southern blot analysis indicates that all five clones came from only one gene existing as a single copy in the 'Sinta' papaya genome. Multiple sequence alignment indicates that the four isoforms arise from a single gene, possibly through alternative splicing mechanisms. All the putative alternative exons were present at the 5'-end of the gene comprising the N-terminal region of the protein. 'Sinta' ACC synthase cDNAs were of the capacs 1 type and are most closely related to a 1.4 kb capacs 1-type DNA(AJ277160) from Eksotika papaya. No capacs 2-type cDNAs were cloned from 'Sinta' by RT-PCR. This is the first report of possible alternative splicing mechanism in ripening-related ACC synthase genes in hybrid papaya, possibly to modulate or fine-tune gene expression relevant to fruit ripening.

• BMB Reports
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• v.40 no.5
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• pp.791-800
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• 2007

Ethylene performs an important function in plant growth and development. 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS), the key enzyme involved in ethylene biosynthesis, has been the focus of most ethylene studies. Here, a cotton ACS gene referred to as Gossypium hirsutum ACS1 (GhACS1), was isolated. The full-length cDNA of GhACS1 encodes for a 476-amino acid protein which harbors seven conserved regions, 11 invariant amino acid residues, and the PLP binding active site, all of which characterize ACC synthases. Alignment analysis showed that GhACS1 shared a high degree of identity with other known ACC synthases from different species. Two introns were detected in the genomic DNA sequence, and the results of Southern blot analysis suggested that there might be a multi-gene family encoding for ACC synthase in cotton. From the phylogenetic tree constructed with 24 different kinds of ACC synthases, we determined that GhACS1 falls into group II, and was closely associated with the wound-inducible ACS of citrus. The analysis of the 5' flanking region of GhACS1 revealed a group of putative cis-acting elements. The results of expression analysis showed that GhACS1 displayed its transient expression nature after wounding, abscisic acid (ABA), and $CuCl_2$ treatments. These results indicate that GhACS1, which was transiently expressed in response to certain stimuli, may be involved in the production of ethylene for the transmission of stress signals.

• Journal of Life Science
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• v.20 no.5
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• pp.745-749
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• 2010

This study was conducted to examine the effect of cytokinin ($N^6$-benzyladenine; BA) and/or an IAA on ethylene production of maize (Zea mays) primary roots. When the two hormones were applied exogenously, both hormones synergistically increased ethylene production, which was greater than the sum of the level of each hormone's effect. For example, the ethylene production was stimulated between about 87% and 170% of the control by $10^{-4}\;M$ BA with $10^{-4}\;M$ IAA for 8 hours respectively, whereas the ethylene production was increased by about 480% of the control when the two hormones were treated simultaneously. Such a synergistic effect was also found in changes in the activity and gene expression level of ACC synthase. However, in the case of ACC oxidase did not show any observable effects. Based on our results, it is possible to conclude that BA and IAA stimulated the ethylene production synergistically by affecting the ACC synthase in maize roots.