• Journal of Life Science
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• v.13 no.1
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• pp.83-89
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• 2003

To investigate the function of chloroplast small heat shock protein (HSP), transgenic tobacco plants (Nicotiana tabacum L, cv. SR-1) that constitutively overexpress the rice chloroplast small HSP (Oshsp26) were generated. Effects of constitutive expression of the Oshsp26 on thermotolerance were investigated with the chlorophyll fluorescence. After 5-min incubation of leaf discs at high temperatures, an increase in the Fo level, indication of separation of LHCII from PSII, was mitigated by constitutive expression of the chloroplast small HSP When tobacco plantlets grown in Petri dishes were incubated at $20^{\circ}C$/TEX> for 45 min and subsequently incubated at $20^{\circ}C$/TEX> leaf color of wild-type plant became gradually white and all plantlets were finally died. Under the conditions in which all the wild-type plants died, more than 80% of the transformants remained green and survived. It was also found that the levels of Oshsp26 protein accumulated in transgenic plants were correlated with the degree of thermotolerance. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery, as a results, increases thermotolerance of whole plant during heat stress.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.15-20
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• 1999

To investigate the function of the chloroplast small heat shock protein (small HSP), transgenic tobacco plants (Nicotiana tabacum L., cv. SRI) that show constitutive expression of the chloroplast small HSP were generated. Effects of constitutive expression of the introduced gene on thermotolerance were first probed with the chlorophyll fluorescence. After a 5-min incubation of leaf discs at high temperatures, an increase in the Fo level and a decrease in the Fv level, indications of separation of LHCII from PSII and inactivation of electron transport reactions in PSII, were mitigated by constitutive expression of the small HSP. When tobacco plantlets grown in Petri dishes were incubated at $52^{\circ}C$ for 45 min and subsequently incubated at $25^{\circ}C$, leaf color of nontransformants was gradually became white and all plantlets finally were died. Under conditions in which all nontransformants were dying, more than 80% of the transformants remained green and survived. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery during heat stress.

• Journal of Plant Biology
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• v.29 no.1
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• pp.41-51
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• 1986

The plants of Nicotiana tabacum L. cv. NC2326 were germinated in 10 cm D$\times$20 cm H polyethylene pot, and sand-cultured with Hoagland solution near by the window of laboratory room(26$\pm$5$^{\circ}C$). The growing plants were sprayed with various concentrations of ABA around 9 : 00 a.m. once in every two days for 12 weeks in summer. As the results, frequency of stomatal number, stomatal opening, chlorophyll content, respiration rate, and protein content in the leaves were decreased with the increasing of concentrations of ABA, respectively. The plant growth was inhibited by exogenous ABA, but leaf abscission was not found during the experimental period. The ratio of three to one in chlorophyll a to b was not altered by exogenous ABA. All the stomata were closed within three minutes by 100 $\mu\textrm{g}$ ml-1 ABA and within seven minutes by 1-10 $\mu\textrm{g}$ ml-1 ABA after the spraying of ABA, and then reopended after a few hours in 1-10 $\mu\textrm{g}$ ml-1 ABA and after 24 hours in 100 $\mu\textrm{g}$ ml-1 ABA. The polar movement of chloroplast within the guard cells was found in the higher concentrations of 10 and 100 $\mu\textrm{g}$ ml-1 ABA, but not found in the lower concentrations than 1 $\mu\textrm{g}$ ml-1 ABA. During the night and weak light, it was fond that the inhibition of respiration rate by the higher concentration of ABA was owing to firstly the stomatal closure by the spraying of ABA and secondly the decrease of stomatal frequency by the inhibition of stomatal development with exogenous ABA for the long period of 12 weeks. In the band number of leaf protein by the electrophoresis, most of the protein bands were disappeared by the higher concentration of 100 $\mu\textrm{g}$ ml-1 ABA, but were not altered by the lower concentration of ABA in comparison with control.

• Journal of Plant Biology
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• v.35 no.1
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• pp.1-8
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• 1992

The characteristic of Cyanophyte genus SG63 is similar to that of Aphanot hece sp. The optimal growth was found with the concentration of NaCI and $MgSO_4{\cdot}7H_2O$ on the culture medium. The most optimal condition is 56%0 of NaCl (S4 medium) and 20%0 of $MgSO_4{\cdot}7H_2O$ (M2 medium). The synthesis of chlorophyll a, phycocyanin and soluble proteins is affected by the concentration of the two mineral elements in culture. Especially, the content of chlorophyll a and phycocyanin decreases on the most highly saline medium. The identified principal carotenoids are ${\beta}-carotene$, echinenone, zeaxanthin and myxoxanthophyll. The rates of concentration of protein/chlorophyll a and phycocyanin/chlorophyll a are low on the S4 medium. Inversely, these rates are the highest on the M2 medium. Accordingly, the high concentration of $MgSO_4{\cdot}7H_2O$ provoke the synthesis of phycocyanin and total proteins.oteins.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.646-651
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• 2007

This investigation was performed to study the influence of Cd and nitrate on growth, and chlorophyll and photosynthetic enzymes in seedling of tobacco. Growth inhibition by Cd was not recovered by nitrate. Chlorophyll levels were reduced by Cd. The combination of Cd and low concentration of nitrate decreased the chlorophyll content compared to that in plants exposed only to Cd. Activity and content of rubisco at Cd treatment was significantly lesser than in plants receiving no treatment, These data suggest that rubisco activity was associated with an amount of rubisco protein, and that the activation and synthesis of rubisco is inhibited by Cd. Both the activity and content of rubisco decreased by Cd were more decreased by nitrate. A similar change pattern was also observed in activity and content of rubisco activase. These results suggest that Cd- and nitrate-induced changes of rubisco could be correlated with rubisco activase, and that nitrate was concerned in not only the activation and synthesis of rubisco directly, but also rubisco activase leading to a large change in rubisco.

• Animal cells and systems
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• v.7 no.4
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• pp.337-343
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• 2003

Methyl jasmonate (MeJA) is a signal molecule in the activation of defense responses in plants. In this study, we isolated 15 MeJA-inducible genes by subtractive hybridization. These genes encode two myrosinase-binding proteins, five lipase-like proteins, a polygalacturonase inhibitor, a putative chlorophyll-associated protein, a terpene synthase, a dehydroascorbate reductase, an ascorbate oxidase, a cysteine protease, an O-methyltransferase, and an epithiospecifier protein. Northern analysis showed that most of the Chinese cabbage genes are barely expressed in healthy leaves, but are strongly induced by MeJA treatment. We also examined whether these MeJA-inducible genes were activated by ethethon, BTH, and Pseudomonas syringae pv. tomato (Pst), a nonhost pathogen of Chinese cabbage. The results showed that none of the MeJA-inducible genes was strongly induced by ethephon or by BTH. The genes encoding lipase-like proteins and a myrosinase-binding protein were weakly induced by Pst. Other MeJA-inducible genes were not activated at all by the pathogen.

• Journal of Photoscience
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• v.8 no.2
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• pp.43-53
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• 2001

a, a parameter that describes how effectively photoinactivated PS II units protect their functional neighbours; car, carotenoids; ΔpH, transthylakoid pH difference; D1 protein, psbA gene product in the PS II reaction centre; f, functional fraction of PS II: F$\_$v//F$\_$m/, the ratio of variable to maximum chlorophyll a fluorescence; k$\_$d/, rate coefficient for degradation of D1 protein; k$\_$i/ and k$\_$r/, rate coefficient for photoinactivation and repair of PS II, respectively; NADP+, oxidized nicontinamide adenine dinucleotide phosphate; P680, the primary electron donor in the PSII reaction centre; Ph, pheophytin; PS, photosystem; Q$\_$A/, first quinone acceptor of an electron in PS II; R$\_$s/, the gross rate of D1 protein synthesis.

• Journal of Plant Biology
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• v.29 no.4
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• pp.255-262
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• 1986

Developmental changes of chlorophyll-protein (CP)-complex and plastid membrane proteins during the greening of rape (Brassica napus L.) cotyledons were examined in order to investigate the effect of benzymladenine (BA) on plastid development. The formation of CP-complexes was slightly promoted by BA treatment in early greening stage, at 24 h and 48 h after illumination. However, BA inhibited the development of CP-complexes at 72 h after illumination. On the profiles of plastid membrane proteins with greening time, it was found that the 24 kd protein was increased and the 56 kd protein was decreased in both water control and BA-treated cotyledons. However, the above two traits were retarded under BA treatment, respectively. From the obtained result, plastid development of rape cotyledon during greening was partially affected by interaction between light and BA dependent on its physiological age.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.124-124
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• 2003

In order to study gene expression in a reproductive organ, we constructed a cDNA library of immature flower buds in Korean ginseng and generated expressed sequence tags (ESTs) of 3,360 clones randomly selected. The ESTs could be clustered into 1,844 non-redundant groups. Similarity search of the non-redundant ESTs against public non-redundant databases of both protein and DNA indicated that 1,254 groups show similarity to genes of known function. These ESTs clones were divided into sixteen categories depending upon gene function. The most abundant transcripts were unknown protein (72), chlorophyll a/b-binding protein (48), and stylar glycoprotein. There are no useful informations of gene expression during the development of flower bud in Korean ginseng. These results could help to understand the development of flower bud in Korean ginseng.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.180-185
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• 2006

We investigated relations between physiological damages and gene expression and enzyme activities of superoxide dismutase(SOD) isoenzymes in leaves of rice (Oriza sativa L. cv. Ilpoombyeo) plants irradiated with a high-dose gamma-ray. Gamma-irradiation with 500 Gy caused significant decreases in the contents of protein, chlorophyll and carotenoid in the rice leaves by 24 h, especially reducing the chlorophyll contents up to 26% relative to the control. In contrast, gene expressions of SOD isoenzymes were kept higher in the irradiated leaves until 24 h after the irradiation than in the control and they started to noticeably decrease at 48 h, finally being lower in the irradiated leaves at 72 h than in the control. In the case of enzyme activities of SOD isoenzymes, some CuZn-SOD isoenzymes showed slightly increased activities until 48 h after the irradiation but at 72 h, all isoenzyme activities markedly decreased in the irradiated leaves below the control levels. In conclusion, 500 Gy gamma-irradiation used in the current study caused decreases in the contents of protein, chlorophyll and carotenoid as symptoms for physiological damages. Although such physiological damages were not directly related to the gene expressions and enzyme activities of SOD isoenzymes until 24 h after the irradiation, the damages at 72 h were reasonably attributable to their reduction.