• Journal of Plant Biology
• /
• v.22 no.4
• /
• pp.95-100
• /
• 1979

As a part of the studies on the regulatory mechanism of gene expression by $GA_{3}$ , the effects of $GA_{3}$ on the protein biosynthesis and phosphorylation in maize seedlings were investigated. 1. The optimum concentration of $GA_{3}$ for the stimulation of the protein biosynthesis was 0.3mM. 2. The protein biosynthesis was remarkably increase by $GA_{3}$ during the germination. The reason for the decrease in the protein biosynthesis by 48hrs. after germination seems to be a staggered gene expression, and/or increases in protease and RNase activities. 3. The ratio of the amount of the newly synthesized protein in germinating seeds treated with $GA_{3}$ to the amount of proteins secreted into the endosperm was similar to that ratio in control. According to this result, it seems that $GA_{3}$ stimulates only the expression of certain definite genes. 4. By the treatment with $GA_{3}$, the rates of biosynthesis and phosphorylation of proteins were increased up to about 1.5 times during germination and 6 times by 72hrs. after germination, respectively. The ratio of the total soluble proteins to the phosphorpoteins considerably increased in the early germination stage (24hrs.) but decreased after 24hrs. According to the above mentioned results, the stimulation of the phosphorylation of proteins of $GA_{3}$ seems to be attributed to the increases in the activities of protein kinases.

• Korean Journal of Weed Science
• /
• v.17 no.2
• /
• pp.207-213
• /
• 1997

This study was conducted to correlate changes in plant growth and flowering behavior with inhibition of gibberellin synthesis following application of GA biosynthesis inhibitor. Two sorghum genotypes, wild-type and phyB-1(phytochrome B mutant) which grow fast and flowers early relative to the wild-type, were used. Both growth and floral initiation of these two genotypes were greatly affected by ancymidol concentration increased. However, these growth inhibition and delayed flowering are almost completely overcome by simultaneous applications of 31.6ppm $GA_3$. The ability of $GA_3$ to reverse the effect of the inhibition on both growth and floral initiation in sorghum suggests a role for native GAs in sorghum flowering. This result was contrast to the fact that in some long day plants GA biosynthesis inhibitors will inhibit shoot elongation but not floral initiation. In sorghum, inhibition of vegetative growth by GA biosynthesis inhibitor is accompanied by a delay in flowering. Ten ppm of ancymidol treatments drastically reduced all early-13-hydroxylation pathway GAs($GA_{12}$, $GA_{53}$, $GA_{19}$, $GA_{20}$, $GA_3$, and $GA_8$) levels.

• Journal of Plant Biology
• /
• v.26 no.1
• /
• pp.1-6
• /
• 1983

In order to investigate the effects of GA3 on RNA biosynthesis, the amounts of rRNA and tRNA in germinating maize seeds were measured. The amount of rRNA in the endospermless seedlings was remarkably increased by GA3 tretment after 48 h of germination, but no effect was observed after 12 h of germination. While the amout of rRNA in 0.5 cm shoots in length was decreased by GA3 treatment, both of the amounts of rRNA and tRNA were increased in 1~1.5 cm shoots. According to the above mentioned results, it may be suggested that RNA biosynthesis is affected by GA3 treatment, and that GA3 participates in the biosynthesis of rRNA rather than tRNA in germinating maize seeds.

• Journal of Plant Biology
• /
• v.25 no.1
• /
• pp.3-8
• /
• 1982

As a part of the studies on the regulatory mechanism of gene expression by gibbrellic acid, the effects of $GA_3$ on the protein biosynthesis and phosphorylation in maize seedlings were investigated in the presence of actinomycin D. The activities of protein biosynthesis and phosphorylation in germinating seeds treated with $GA_3$ were greater than those of the control at the 3-day point after germination. It is assumed that the enhancement of protein biosynthesis by $GA_3$ in the presence of actinomycin D is due to the effects of $GA_3$ on the translational processes in which protein is produced from the mRNA synthesized previously.

• Korean Journal of Breeding Science
• /
• v.43 no.1
• /
• pp.1-13
• /
• 2011

Low temperature stress is one of the major negative factors affecting vegetative and reproductive growth of rice. To better understand responses of rice plants to low temperature we analyzed transcriptome expression patterns in glumous flower of cold-tolerant japonica rice variety, Stejaree45, and cold-susceptible variety, HR19621-AC6 at booting stage under cold water irrigation. A total of 2,411 probes were differentially expressed by low temperature in glumous flowers of the two varieties. Some important genes involved in hormone biosynthesis showed variety-specific regulation. Expression of GA20ox3 and GA2ox, among the genes involved in GA biosynthesis, was regulated differentially in the two varieties. Among the genes involved in IAA biosynthesis, YUCCA1 and TAA1:1 showed variety-specific regulation. Among the genes involved in cytokinin biosynthsis and signaling, expression of LOG, HK1 and HK3 was significantly down-regulated only in the cold-susceptible variety. Among the genes involved in ABA biosynthesis, NSY and AAO3 were down-regulated only in the cold-tolerant variety. In general, genes involved in GA, IAA and cytokinin biosynthesis responded to cold temperature in such a way that capacity of those bioactive hormones is maintained at relatively higher levels under cold temperature in the cold-tolerant variety, which can help minimize cold stress imposed to developing reproductive organs in the cold-tolerant variety.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.17 no.2
• /
• pp.115-124
• /
• 1988

This study was carried out to realize the effect of gibberllic acid$(GA_3)$, 1-naphthaleneacetic acid(NAA) and indole-3-acetic acid(IAA) on the biosynthesis of vitamin C. The relation between carbohydrate metabolism and vitamin C production in soybean sprouts was also investigated. Growth, vitamin C content, protein, galactonolactone dehydrogenase(GLD), ribulose diphosphate carboxylase(RuDpCO) and RNA level in the plastid and cytoplasm were determined. The effects of protein and respiratory inhibitors on the growth and vitamin C production were also examined. The most favourable growth of soybean sprouts was observed at the level of NAA $10^{-8}M,\;IAA10^{-6}M\;and\;GA_3\;10^{-5}M$ in the single treatment, respectively, and also favourable at levels of $GA_3\;10^{-5}M+NAA\;10^{-9}M\;and\;GA_3\;10^{-5}M+IAA\;10^{-9}M$ in the case of mixed treatment. The excellent growth was observed at the level IAA $10^{-6}M$ among all the single and mixed treatments. When the soybean sprouts were treated with NAA $10^{-8}M,\;IAA\;10^{-6}M\;GA_3\;10^{-5}M,\;GA_3\;10^{-8}M+IAA\;10^{-6}M,\;and\;GA_3\;10^{-5}M+IAA\;10^{-9}M$, the maximum growth rate was observed at the level of IAA $10^{-6}M$ and the conten of vitamin C was 24.26mg% which was 1.6 times higher than that of the control. RuDpCO was inhibited by the chloramphenicol at the concentration that did not inhibit the growth but the activities of NADP-GDH, GLD and vitamin C content were not affected. These results showed that the biosynthesis of viamin C had nothing to do with the activity of chloroplastic RNA but with cytoplasm. The highest vitamin C content was found at the the level of IAA $10^{-6}M$, where the GLD activity increased up 1.8 times of the control. The concentration of IAA $10^{-6}M$ promoted the biosynthesis of RNa and protein both in chloroplast and cytoplasm, especially in the cytoplasm. Thus it suggeted that IAA affected vitamin C biosynthesis by regulating RNA level in the cytoplasm. 2,4-Dinitrophenol as an uncoupler of oxidative phosphorylation did not inhibit the vitamin C biosynthesis, however, all of the respiratory inhibitors severely inhibited the growth and vitamin C biosynthesis.

• Journal of Plant Biology
• /
• v.35 no.4
• /
• pp.371-383
• /
• 1992

The effects of IAA $(10^{-3}M)\;an;GA_3\;(2{\times}10^{-8}\;M)$ on the biosynthesis of phospholipids and their fatty acid compositions in chloroplast isolated from Chlorella ellipsidea were analyzed. Growth ratio and the levels of total lipids and phospholipids in whole cell system and chloroplast treated with phytohormones were higher than those of control, and when treated with GAl. phosphatidylcholine content was predominantly higher than that of control. It was showed that in whole cell system the fatty acid utilized for biosynthesis of phopholipids was 27.43% for palmitic acid in control, while that was 20.25% for linolenic acid in treatment with 1M. In treatment with $GA_3$, 23.17% for linolenic acid was used in phospholipid formation. The major fatty acid in the chloroplst system was analyzed to be 35.67% for palmitic acid in control and in treatment with 1M, 24.91% for linolenic acid was used in phospholipid formation, while in treatment with $GA_3$, major fatty acid of phospholipids was 22.80% for linoleic acid.c acid.

• Horticultural Science & Technology
• /
• v.29 no.3
• /
• pp.165-171
• /
• 2011

Plant growth retardants reduce the plant height by inhibiting stem elongation in Lilium davuricum. To investigate the plant hormones related to stem elongation, we sprayed 50 $mg{\cdot}L^{-1}$ diniconazole to young plants of L. davuricum and quantified the contents of endogenous gibberellic acids (GA) and abscisic acid (ABA). In GA biosynthesis, L. davuricum had not only the early C-13 hydroxylation ($GA_{19}{\rightarrow}GA_{20}{\rightarrow}GA_1$) pathway resulting in $GA_1$ as the active form but also the non C-13 hydroxylation (NCH, $GA_{12}{\rightarrow}GA_{24}{\rightarrow}GA_9{\rightarrow}GA_4$) with $GA_4$ as the active form. However, the main pathway was NCH because $GA_4$ concentration of 55 $ng{\cdot}g^{-1}$ dry wt was much higher than $GA_1$ content of 0.23 $ng{\cdot}g^{-1}$ dry wt in control plant. Diniconazole inhibited GA biosynthesis through NCH pathway from its early stage. $GA_{12}$ content decreased by diniconazole up to 6% level of that of control and this effect continued to $GA_4$. Diniconazole reduced $GA_{12}$ content by 12.7 $ng{\cdot}g^{-1}$ dry wt, whereas that of control plant was 213.8 $ng{\cdot}g^{-1}$ dry wt. ABA content decreased up to one third of control by diniconazole application. From the contents of endogenous $GA_4$, $GA_1$, and ABA in this study, we could conclude that diniconazole reduces the plant height by inhibiting $GA_4$ biosynthesis in L. davuricum.

• Journal of Radiation Industry
• /
• v.6 no.3
• /
• pp.281-287
• /
• 2012

The model plant, Arabidopsis thaliana is the subject of an international genome research project. Massive doses of ionizing radiation have been shown to induce physiological changes in plants. The wild-type (Ler) Arabidopsis plants were irradiated with 100 Gy and 800 Gy of gamma-ray. Gibberellin (GA) affects developmental processes and responses according to the various environment conditions in diverse plant. The 13 GA isomers were analyzed at vegetative (VE) and reproductive (RE) stages by HPLC. Total GA contents were reduced with the increase in radiation doses at VE and RE stages. Specifically, levels of GA3, GA4, GA12, and GA34 were significantly reduced with the increase of radiation doses. Oligonucleotide microarrays analysis was performed with Arabidopsis plants at different developmental stages and doses of gamma-ray. Through the microarray data, we isolated 41 genes related to GA biosynthesis and signaling transduction. Expression of these genes was also decreased as the reduction of GA contents. Interestingly, in GA signaling related gene expression, gibberellin-responsive protein, putative (At2g18420) was down-regulated at VE and RE stages. Myb21 (At3g27810), Myb24 (At5g40350), and Myb57 (At3g01530) was down-regulated at RE stage. In GA biosynthesis related gene expression, YAP169 (At5g07200) and GA20ox2 (At5g51810) were down-regulated at 100 Gy treatment of VE stage and 800 Gy treatment of RE stage in cytoplasm, respectively. However, exceptively, GA3ox2 (At1g80340) was up-regulated at 100 Gy treatment of RE stage in cytoplasm. In this study, the wild type (Ler) Arabidopsis plants showed differences in response with development stage at the various doses of gamma-rays. GA contents change was reported in gamma irradiated plant.

• Journal of Plant Biotechnology
• /
• v.48 no.3
• /
• pp.186-192
• /
• 2021

The roots of Korean ginseng (Panax ginseng) have a long history of usage as a medicinal drug. Ginsenosides, a group of triterpenioid saponins in ginseng, have been reported to show important pharmacological effects. Many studies have attempted to identify the ginsenoside synthesis pathways of P. ginseng and to increase crop productivity. Recent studies have shown that exogenous gibberellin (GA) treatments promote storage root secondary growth by integration of the modulating cambium stem cell homeostasis with a secondary cell wall-related gene network. However, the dynamic regulation of ginsenoside synthesis-related genes and their contents by external signaling cues has been rarely evaluated. In this study, we confirmed that GA treatment not only enhanced the secondary growth of P. ginseng storage roots, but also significantly enriched the terpenoid biosynthesis process in RNA-seq analysis. Consistently, we also found that the expression of most genes involved in the ginsenoside synthesis pathways, including those encoding methylerythritol-4-phosphate (MEP) and mevalonate (MVA), and the saponin content in both leaves and roots was increased by exogenous GA application. These results can be used in future development of biotechnology for ginseng breeding and enhancement of saponin content.