• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.90-90
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• 2017

Regulation of seed dormancy is important in many grains to prevent pre-harvest sprouting. To identify and understand the gene related to seed dormancy regulation, we have screened for viviparous phenotypes of rice mutant lines generated by insertion of Ds transposon in a Korean Japonica cultivar (Dongjin) background. One of the mutants, which represented viviparous phenotype, was selected for further seed dormancy regulation studies and designated dor1. The dor1 mutant has single Ds insertion in the second exon of OsDor1 gene encoding glycine-rich protein. The seeds of dor1 mutant showed a higher germination potential and reduced abscisic acid (ABA) sensitivity compared to wild type Dongjin. Over-expression of Dor1 complements the viviparous phenotype of dor1 mutant, indicating that Dor1 function in seed dormancy regulation. Subcellular localization assay of Dor1-GFP fusion protein revealed that the OsDor1 protein mainly localized to membrane and the localization of OsDOR1 was influenced by presence of a giberelin (GA) receptor OsGID1. Further bimolecular fluorescence complementation (BiFC) analysis indicated that OsDOR1 interact with OsGID1. The combined results suggested that OsDOR1 regulates seed dormancy by interacting with OsGID1 in GA response. Additionally, expression of OsDOR1 partially complemented the cold sensitivity of Escherichia coli BX04 mutant lacking four cold shock proteins, indicating that OsDOR1 possessed RNA chaperone activity.

• BMB Reports
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• v.42 no.8
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• pp.486-492
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• 2009

OsDREB1D, a special DREB (dehydration responsive element binding protein) homologous gene, whose transcripts cannot be detected in rice (Oryza sativa L), either with or without stress treatments, was amplified from the rice genome DNA. The yeast one-hybrid assay revealed that OsDREB1D was able to form a complex with the dehydration responsive element/C-repeat motif. It can also bind with a sequence of LTRE (low temperature responsive element). To analyze the function of OsDREB1D, the gene was transformed and over-expressed in Arabidopsis thaliana cv. Columbia. Results indicated that the over-expression of OsDREB1D conferred cold and high-salt tolerance in transgenic plants, and that transgenic plants were also insensitive to ABA (abscisic acid). From these data, we deduced that this OsDREB1D gene functions similarly as other DREB transcription factors. The expression of OsDREB1D in rice may be controlled by a special mechanism for the redundancy of function.

• The Plant Pathology Journal
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• v.35 no.2
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• pp.178-187
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• 2019

Plants are exposed to biotic stresses caused by pathogen attack and complex abiotic stresses including heat and drought by dynamic climate changes. To alleviate these stresses, we investigated two bacterial stains, H26-2 and H30-3 in two cultivars ('Ryeokkwang' and 'Buram-3-ho') of Chinese cabbage in plastic pots in a greenhouse. We evaluated effects of bacterial strains on plant growth-promotion and mitigation of heat and drought stresses; the role of exopolysaccharides as one of bacterial determinants on alleviating stresses; biocontrol activity against soft rot caused by Pectobacterium carotovorum subsp. carotovorum PCC21. Strains H26-2 and H30-3 significantly increased fresh weights compared to a $MgSO_4$ solution; reduced leaf wilting and promoted recovery after re-watering under heat and drought stresses. Chinese cabbages treated with H26-2 and H30-3 increased leaf abscisic acid (ABA) content and reduced stomatal opening after stresses treatments, in addition, these strains stably colonized and maintained their populations in rhizosphere during heat and drought stresses. As well as tested bacterial cells, exopolysaccharides (EPS) of H30-3 could be one of bacterial determinants for alleviation of tested stresses in Chinese cabbages, however, the effects were different to cultivars of Chinese cabbages. In addition to bacterial activity to abiotic stresses, H30-3 could suppress incidence (%) of soft rot in 'Buram-3-ho'. The tested strains were identified as Bacillus aryabhattai H26-2 and B. siamensis H30-3 based on 16S rRNA gene sequence analysis. Taken together, H26-2 and H30-3 could be candidates for both plant growth promotion and mitigation of heat and drought stresses in Chinese cabbage.

• Molecules and Cells
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• v.27 no.4
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• pp.423-428
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• 2009

Superoxide dismutases (SODs) constitute the first line of cellular defense against oxidative stress in plants. SODs generally occur in three different forms with Cu/Zn, Fe, or Mn as prosthetic metals. We cloned the full-length cDNA of the Thellungiella halophila Cu/Zn-SOD gene ThCSD using degenerate RT-PCR and rapid amplification of cDNA ends (RACE). Sequence analysis indicated that the ThCSD gene (GenBank accession number EF405867) had an open reading frame of 456 bp. The deduced 152-amino acid polypeptide had a predicted molecular weight of 15.1 kDa, an estimated pI of 5.4, and a putative Cu/Zn-binding site. Recombinant ThCSD protein was expressed in Escherichia coli and assayed for SOD enzymatic activity in a native polyacrylamide gel. The SOD activity of ThCSD was inactivated by potassium cyanide and hydrogen peroxide but not by sodium azide, confirming that ThCSD is a Cu/Zn-SOD. Northern blotting demonstrated that ThCSD is expressed in roots, stems, and leaves. ThCSD mRNA levels increased by about 30-fold when plants were treated with sodium chloride (NaCl), abscisic acid (ABA), and indole-acetic acid (IAA) and by about 50-fold when treated with UVB light. These results indicate that ThCSD is involved in physiological pathways activated by a variety of environmental conditions.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.69-75
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• 2017

Dormancy-associated protein (DRM) is involved in the dormancy physiology of plants and is conserved in almost all plant species. Recent studies found that DRM genes are involved in the abiotic stress response, and characterization studies of these genes have been conducted in several plants. However, few studies have focused on DRM genes in woody plants. Therefore, in this study, cDNA coding for DRM (PagDRM1) was isolated from poplar (Populus alba ${\times}$ P. glandulosa), and its structure and expression characteristics were investigated. PagDRM1 encodes a putative protein composed of 123 amino acids, and the protein contains two conserved domains (Domain I and Domain II). PagDRM1 is present as one or two copies in the poplar genome. Its expression level was highest in the stem, followed by mature leaves, roots, and flowers. During the growth of cultured cells in suspension, PagDRM1 was highly expressed from the late-exponential phase to the stationary phase. In addition, PagDRM1 expression increased in response to drought, salt stress, and treatment with plant hormones (e.g., abscisic acid and gibberellic acid). Therefore, we suggested that PagDRM1 not only plays an important role in the induction of dormancy, but also contributes to stress tolerance in plants.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.46-50
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• 2013

Some rhizobacteria producing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase can make plant to continue growth under the stress conditions through lowering the level of phytohormone, ethylene which inhibits the plant growth and accelerates plant aging. In this study, some rhizobacteria producing ACC deaminase have been isolated from the rhizosphere of plants grown at sand beaches, and identified as Escherichia hermannii m-2, Enterobacter asburiae m-4, Pseudomonas thivervalensis BD2-26 and Pseudomonas brassicacearum subsp. neoaurantiaca BD3-35 through sequencing of 16S rRNA genes. Strain BD3-35 showed the highest activity of ACC deaminase among the isolates, 20.26 ${\alpha}$-ketobutyrate ${\mu}M/mg$ protein/h. Strains BD3-35 and BD2-26 secreted a phytohormone cytokinin, and strains m-4 and m-2 could produce auxin and abscisic acid, respectively. When these bacteria were applied to the 7-day old tomato plant under drought stress for 7 days, strains BD3-35, m-2, and m-4 increased the length of tomato root by 14, 15, and 35%, respectively, and strains m-2, BD2-26 and BD3-35 increased the dry weight of tomato plant by 22, 33, and 68%, respectively compared to the uninoculated control tomatoes. Therefore, these rhizobacteria may be utilized as a microbial fertilizer for the plants under drought stress.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.388-398
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• 2020

Watermelon yield mainly depends on soil water content controlled by irrigation in a plastic greenhouse. In this study, we investigated the effect of different soil moisture contents affected by irrigation starting point on growth, yield, and physiological responses of small-sized watermelons. Irrigation was initiated at 5 different levels of soil water content as a starting point with soil moisture detecting sensor after 14 days of transplanting, and stopped at 7 ~ 10 days before harvest. These treatments were compared with the conventional periodic irrigation as control. When soil had the lowest moisture content (-50 kPa), the overall shoot growth was retarded, but the root length and root dry weight increased. The photosynthetic parameters (photosynthetic rate, stomatal conductance, and transpiration rate) of watermelon leaves decreased significantly in the lowest soil moisture content (-50 kPa). On the other hand, the photosynthetic rates of watermelon leaves grown with irrigation starting point between -20 and -40 kPa were observed to be higher than those of other treatments. Fruit set rate and marketable fruit yield increased significantly at -30 kPa and -40 kPa. Proline, abscisic acid (ABA), total phenol and citrulline, which are known to contribute to stress tolerance under drought condition, increased as soil water content decreased, particularly, the largest increases were recorded at -50 kPa. From these results, it was found that an appropriate water supply adjusted with an irrigation starting point between -30 and -40 kPa could help to keep favorable soil water content during the cultivation of small-sized watermelons, promoting the marketable fruit production as well as inducing the vigorous plant growth and reproductive development.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.1
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• pp.37-71
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• 2021

Rapeseed is a typical winter crop, and its freezing stress tolerance is a major feature for winter survival. Therefore, it is important to comprehend clearly the physical and molecular mechanisms of rapeseed under freezing stress conditions. This study investigates the physical and transcriptome changes of two rapeseed lines, 'J8634-B-30' and 'EMS26', under cold acclimation and freezing temperature treatments. The proline content of 'J8634-B-30' at 5 ℃ increased 8.7-fold compared to that before treatment, and there was no significant change in that of 'EMS26' RNA-sequencing analysis revealed 5,083 differentially expressed genes (DEGs) of 'J8634-B-30' under cold acclimation condition. Among the genes, 2,784 (54.8%) were up-regulated and 2,299 (45.2%) were down-regulated. The DEGs of 'EMS26' under cold acclimation condition were 5,831 genes, and contained 2,199 up-regulated genes (37.7%) and 3,632 down-regulated genes (62.3%). Among them, only DEGs annotated in the cold response-related signaling pathways were selected, and their expression in the two rapeseed lines was compared. Comparative DEGs analysis indicated that cold response related signaling pathways are proline metabolism and ABA (Abscisic acid) signaling. And ICE (Inducer of CBF expression) - CBF (C-repeat-binding factor) - COR (Cold-regulated) signaling were the significantly differentially expressed transcripts in the two rapeseed lines. The major induced transcripts of 'J8634-B-30' induced P5CS (Δ'-pyrroline-5-carboxylate synthetase), which is related to proline biosynthesis, PYL (pyrabactin resistance-like protein, ABA receptor) and COR413 (cold-regulated 413 plasma membrane 1). In conclusion, these result provide a foundation for understanding the mechanisms of freezing stress tolerance in rapeseeds. Further functional studies should be performed on the freezing stress-related genes identified in this study, which can contribute to the transgenic and molecular breeding for freezing stress tolerance in rapeseed.

• Korean Journal of Weed Science
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• v.18 no.2
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• pp.136-145
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• 1998

This study was conducted to determine the growth characteristics, and the effect of plant growth regulators on the sprouting and growth of purple nutsedge(Cyperus rotundus L.) in order to establish effective control system in lawn ground. The flowering of purple nutsedge was initiated 30 days after transplanting regardless of the transplanting time. Low temperature less than $10^{\circ}C$ after flowering was required for tuber formation, showing that the tuberization was related to air temperature. Shoot number and dry weight of underground portion of purple nutsedge was slightly affected by plant growth regulators such as benzylamino purine, abscisic acid, brassinosteroid and jasmonate. Imazaquin applied at 1, 2 and 3 weeks after transplanting induced multi-shooting and inhibited shoot growth indicating that the herbicide played a role as plant growth regulator at a concentration of 30 and 60g ai/10a. The greatest inhibition of purple nutsedge was obtained by pyrazosulfuron-ethyl as applied 1 weeks after transplanting, showing almost 100% control of purple nutsedge. Tuber of purple nutsedge composed of 61.83% of moisture, 31.60% of carbohydrates, 4.03% of crude protein, 1.57% of crude fat and 0.97% of crude ash.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.320-327
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• 2021

Freezing damage to fruit trees is frequently occurring due to cold in winter and low temperature in spring to abnormal weather caused by global warming. In particular, the freezing injury of deciduous fruit trees is highly dependent on the developmental stages of the flower buds. And the cold resistance is weakened as the growth progresses, so it is most vulnerable period from flowering to petal fall(post-bloom). Therefore, this study was conducted to analyze the cause of the freezing injury caused by severe low temperature to 'Fuji', which has a late flowering period more than 'Hongro' in April 2020. We investigated freezing injury rate in 'Fuji' and 'Hongro' apple trees damaged by natural low temperature at Boeun-gun, Chungbuk province in Korea. In addition, flower buds in the same developmental stage (tight cluster) were treated artificially low temperature to investigate the injury rate for accurate comparative analysis between varieties, and to analyze the soluble sugar and hormone contents in the flower buds. As a result of survey in natural low temperature, 'Fuji' had a higher injury rate than 'Hongro' in both orchards, and in particular, B orchard 'Fuji' had the highest injury rate of 60.5%. Also there were significantly difference in the freezing injury rate between 'Fuji' and 'Hongro' in artificially low temperature treatments. As a result of analyzing the soluble sugar contents in 'Hongro' was higher than 'Fuji'. Also ABA, IAA and SA contents were more increased in the damaged tissue than in the normal flower buds by low temperature treatments. Consequently, it was assumed that the freezing injury was closely related to soluble sugar contents in the flower buds. In particular, the freezing injury rate was negatively correlated with the sorbitol contents.