• Journal of Life Science
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• v.30 no.6
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• pp.570-579
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• 2020

Pre-mRNA splicing is a crucial step for the expression of information encoded in eukaryotic genomes. Alternative splicing occurs when splice sites are differentially recognized and more than one transcript and potentially multiple proteins are generated from the same pre-mRNA. The decision on which splice sites are selected under particular cellular conditions is determined by the interaction of proteins, globally designated as splicing factors, that guide spliceosomal components, and thereby the spliceosome, to their respective splice sites. Abiotic stresses such as heat, cold, salt, drought, and hypoxia markedly alter alternative splicing patterns in plants, and these splicing events implement changes in gene expression for adaptive responses to adverse environments. Alteration of the expression or activity of splicing factors results in alternative splicing under cold, heat, salt, or drought conditions, and alternatively spliced isoforms respond distinctly in several aspects such as expression in different tissues or degradation via nonsense-mediated decay. Spliced isoforms may vary in their subcellular localization or have different biological functions under stress conditions. Despite numerous studies, functional analyses of alternative splicing have been limited to particular abiotic stresses; the molecular mechanism of alternative splicing in abiotic stress response remains uncovered which suggests that further studies are needed in this area.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.180-188
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• 2019

Auxin plays a crucial regulatory role in plant growth and development processes. Three major classes of auxin-responsive transcription factors controlled by the Auxin/indole-3-acetic acid (Aux/IAA), Gretchen Hagen 3 (GH3), and small auxin up RNA (SAUR) genes regulate auxin signaling. Aux/IAA, in particular, encodes short-lived nuclear proteins that accumulate rapidly in response to auxin signaling. In this study, we isolated a PagAux/IAA1 gene from poplar (Populus alba ${\times}$ P. glandulosa) and investigated its expression characteristics. The PagAux/IAA1 cDNA codes for putative 200 amino acids polypeptide containing four conserved domains and two nuclear localization signals (NLSs). Utilizing Southern blot analysis, we confirmed that a single copy of the PagAux/IAA1 gene was present in the poplar genome. The expression of this gene is specific to leaves and flowers of the poplar. PagAux/IAA1 expressed in the early exponential growth phase of cell-cultured in suspension. PagAux/IAA1 expression level reduced in drought and salt stress conditions, and the presence of plant hormones such as abscisic acid. However, expression enhanced in cold stress, cambial cell division, and presence of plant hormones such as gibberellic acid and jasmonic acid. Thus, these results suggest that PagAux/IAA1 participates in cold stress response as well as developmental processes in the poplar.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.684-693
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• 2014

Abiotic stress conditions such as cold, drought, and salinity trigger physiological and morphological changes and yield loss in plants. Hence, plants adapt to adverse environments by developing tolerance through complex regulation of genes related to various metabolic processes. This study was conducted to construct a coexpression network for multidirectional analysis of salt-stress response genes in Brassica rapa (Chinese cabbage). To construct the coexpression network, we collected KBGP-24K microarray data from the B. rapa EST and microarray database (BrEMD) and performed time-based expression analyses of B. rapa plants. The constructed coexpression network model showed 1,853 nodes, 5,740 edges, and 142 connected components (correlation coefficient > 0.85). On the basis of the significantly expressed genes in the network, we concluded that the development of salt tolerance is closely related to the activation of $Na^+$ transport by reactive oxygen species signaling and the accumulation of proline in Chinese cabbage.

• BMB Reports
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• v.41 no.10
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• pp.693-698
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• 2008

The full-length cDNA of LebZIP2 (Lycopersicon esculentum bZIP2) encodes a protein of 164 amino acids and contains a N-terminal basic-region leucine zipper domain. Analysis of the deduced tomato LebZIP2 amino acid sequence revealed that it shares 85% sequence identity with both tobacco bZIP and pepper CcbZIP. LebZIP2 mRNA is expressed at a high level exclusively in flowers. Presently, LebZIP2 was strongly increased also following NaCl and mannitol treatments. No significant LebZIP2 expression was evident following cold treatment. Transient LebZIP2 overexpression resulted in increased NbNOA1 and NbNR transcript levels in Nicotiana benthamiana leaves. Our results indicate that LebZIP2 might play roles as an abiotic stress-signaling pathway and as a transcriptional regulator of the NbNOA1 or NbNR genes.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.7-7
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• 2017

Unfavorable weather and soil conditions reduce rice yield and land and water productivity, aggravating existing encounters of poverty and food insecurity. These conditions are foreseen to worsen with climate change and with the unceasing irrational human practices that progressively debilitate productivity despite global appeals for more food. Our understanding of plant responses to abiotic stresses is advancing and is complex, involving numerous critical processes - each controlled by several genetic factors. Knowledge of the physiological and molecular mechanisms involved in signaling, response and adaptation, and in some cases the genes involved, is advancing. Moreover, the genetic diversity being unveiled within cultivated rice and its wild relatives is providing ample resources for trait and gene discovery, and this is being scouted for rice improvement using modern genomics and molecular tools. Development of stress tolerant varieties is now being fast-tracked through the use of DNA markers and advanced breeding strategies. Large numbers of drought, submergence and salt tolerant varieties were commercialized over recent years in South and Southeast Asia and more recently in Africa. These varieties are making significant changes in less favorable areas, transforming lives of smallholder farmers - progress considered incredulous in the past. The stress tolerant varieties are providing assurance to farmers to invest in better management of their crops and the ability to adjust their cropping systems for even higher productivity and more income, sparking changes analogous to that of the first green revolution, which previously benefited only favorable irrigated and rainfed areas. New breeding tools using markers for multiple stresses made it possible to develop more resilient, higher yielding varieties to replace the aging and obsolete varieties still dominating these areas. Varieties with multiple stress tolerances are now becoming available, providing even better security for farmers and lessening their production risks even in areas affected by complex and overlapping stresses. The progress made in these less favorable areas triggered numerous favorable changes at the national and regional levels in several countries in Asia, including adjusting breeding and dissemination strategies to accelerate outreach and enabling changes at higher policy levels, creating a positive environment for faster progress. Exploiting the potential of these less productive areas for food production is inevitable, to meet the escalating global needs for more food and sustained production systems, at times when national resources are shrinking while demand for food is mounting. However, the success in these areas requires concerted efforts to make use of existing genetic resources for crop improvement and establishing effective evaluation networks, seed production systems, and seed delivery systems to ensure faster outreach and transformation.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.347-358
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• 2016

Brassinosteroid (BR), a plant steroid hormone, plays key roles in numerous growth and developmental processes as well as tolerance to both abiotic and biotic stress. To understand the biological networks involved in BR-mediated signaling pathways and stress tolerance, we performed comparative genome-wide transcriptome analysis of a constitutively activated BR bes1-D mutant with an Agilent Arabidopsis $4{\times}44K$ oligo chip. As a result, we newly identified 1,091 (562 up-regulated and 529 down-regulated) significant differentially expressed genes (DEGs). The combination of GO enrichment and protein network analysis revealed that stress-related processes, such as metabolism, development, abiotic/biotic stress, immunity, and defense, were critically linked to BR signaling pathways. Among the identified gene sets, we confirmed more than a 6-fold up-regulation of NB-ARC and FLS2 in bes1-D plants. However, some genes, including TIR1, TSA1 and OCP3, were down-regulated. Consistently, BR-activated plants showed higher tolerance to drought stress and pathogen infection compared to wild-type controls. In this study, we newly developed a useful, comprehensive method for large-scale identification of critical network and gene sets with global transcriptome analysis using a microarray. This study also showed that gain of function in the bes1-D gene can regulate the adaptive response of plants to various stressful conditions.

• Korean Journal of Plant Tissue Culture
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• v.27 no.5
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• pp.415-421
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• 2000

The disaccharide trehalose ($\alpha$-D-glucopyranosyl-$\alpha$-D-glucopyranoside) is found in variety of organ-isms that are able to withstand almost complete desiccation. In order to identify the function of trehalose in plants, we isolated Arabidopsis trehalase (AtTRE) gene that encodes the enzyme able to hydrolyze trehalose to glucose, and trehalose-6-phosphate synthase isolog, TPS3 gene by RT-PCR. The AtTRE had the substrate specificity to hydrolyze only trehalose, and a broad pH range of enzyme activity. The AtTRE promoter/GUS reporter gene was expressed in cotyledons, mature leaf tissues including guard cells, and developing siliques. The GUS expression driven by AtTPS3 promoter was significant in root tissues, and the level of GUS activity was much higher than that of the pBll 21 control seedlings. The knockout of AtTPS3 gene in Arabidopsis resulted in the retarded root development, whereas the overexpression of AtTPS3 increased the root elongation in the presence of sucrose in MS medium. Possible functions of AtTRE and AtTPS3 in plant will be discussed. In addition, ectopic expression of yeast TPS1 driven by the inducible promoters in tobacco and potato conferred the plants on the drought and freezing tolerances.

• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.189-195
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• 2014

Basic leucine zipper (bZIP) protein is a regulatory transcription factor that plays crucial roles in growth, development and stress response of plant. In this study, we isolated a PagbZIP1 gene that belonged to Group SE3 of bZIP from Populus alba ${\times}$ P. glandulosa, and investigated its expressional characteristics. The PagbZIP1 is 844 base pairs long and encodes a putative 144-amino-acid protein with an expected molecular mass of 16.6 kDa. The PagbZIP1 has two conserved domains including the basic and leucine zipper portions. Southern blot analysis revealed that two copies of the gene are presented in the poplar genome. PagbZIP1 was specifically expressed in the root and suspension cells. Moreover, the expression of PagbZIP1 was induced by drought, salt, cold and ABA. Therefore, our results indicated that PagbZIP1 might be expressed in response to abiotic stress through the ABA-mediated signaling pathway in poplar.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.194-200
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• 2014

Monodehydroascorbate reductase (MDHAR) is an important enzyme that plays a role in the detoxification of reactive oxygen species (ROS) by maintaining reduced pool of ascorbate through recycling the oxidized form of ascorbate. In this study, we isolated a PagMDHAR1 gene from Populus alba ${\times}$ P. glandulosa, and investigated its expression characteristics. The PagMDHAR1 cDNA encodes a putative 434 amino acids containing FAD- and NAD(P)H-binding domains. Southern blot analysis indicated that a single nuclear gene encodes this enzyme. Northern hybridization analysis revealed that PagMDHAR1 is highly expressed in both suspension cells and flower tissues, while its expression levels were enhanced by drought, salt, cold, wounding and ABA. Therefore, PagMDHAR1 might be expressed in response to abiotic stress through the ABA-mediated signaling pathway in this poplar species, suggesting that the PagMDHAR1 plays an important role in the defense mechanisms against oxidative stress.