Publications by authors named "Hyo-Jun Lee"

49 Publications

Catalyzing Initial Responses to Environmental Stresses.

Trends Plant Sci 2021 Mar 8. Epub 2021 Mar 8.

Department of Chemistry, Seoul National University, Seoul 08826, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea. Electronic address:

Plants have evolved stress-sensing machineries that initiate rapid adaptive environmental stress responses. Cytosolic calcium ion (Ca) is the most prominent second messenger that couples extracellular signals with specific intracellular responses. Essential early events that generate a cytosolic Ca spike in response to environmental stress are starting to emerge. We review sensory machineries, including ion channels and transporters, which perceive various stress stimuli and allow cytosolic Ca influx. We highlight integrative roles of Ca channels in plant responses to various environmental stresses, as well as possible interplay of Ca with other early signaling components, which facilitates signal propagation for systemic spread and spatiotemporal variations in respect to external cues. The early Ca signaling schemes inspire the identification of additional stress sensors.
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http://dx.doi.org/10.1016/j.tplants.2021.02.007DOI Listing
March 2021

Complete genome sequence of artemisia virus B, a new polerovirus infecting Artemisia princeps in South Korea.

Arch Virol 2021 May 1;166(5):1495-1499. Epub 2021 Mar 1.

Plant Systems Engineering Research Center, Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea.

The complete genome sequence of a new polerovirus found naturally infecting Artemisia princeps, artemisia virus B (ArtVB), was determined using high-throughput sequencing. The ArtVB genome comprises 6,141 nucleotides and contains six putative open reading frames (ORF0 to ORF5) with a genome structure typical of poleroviruses. A multiple sequence alignment showed that the complete ArtVB genome shares 50.98% nucleotide sequence identity with ixeridium yellow mottle virus 1 (IxYMaV-1, GenBank accession no. KT868949). ArtVB shares the highest amino acid sequence identity in P0 and P3-P5 (21.54%-51.69%) with other known poleroviruses. Phylogenetic analysis indicated that ArtVB should be considered a member of a new species within the genus Polerovirus, family Luteoviridae.
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http://dx.doi.org/10.1007/s00705-021-05004-2DOI Listing
May 2021

Genome-wide identification of major genes and genomic prediction using high-density and text-mined gene-based SNP panels in Hanwoo (Korean cattle).

PLoS One 2020 2;15(12):e0241848. Epub 2020 Dec 2.

Division of Animal and Dairy Science, Chungnam National University, Daejeon, Korea.

It was hypothesized that single-nucleotide polymorphisms (SNPs) extracted from text-mined genes could be more tightly related to causal variant for each trait and that differentially weighting of this SNP panel in the GBLUP model could improve the performance of genomic prediction in cattle. Fitting two GRMs constructed by text-mined SNPs and SNPs except text-mined SNPs from 777k SNPs set (exp_777K) as different random effects showed better accuracy than fitting one GRM (Im_777K) for six traits (e.g. backfat thickness: + 0.002, eye muscle area: + 0.014, Warner-Bratzler Shear Force of semimembranosus and longissimus dorsi: + 0.024 and + 0.068, intramuscular fat content of semimembranosus and longissimus dorsi: + 0.008 and + 0.018). These results can suggest that attempts to incorporate text mining into genomic predictions seem valuable, and further study using text mining can be expected to present the significant results.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0241848PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710051PMC
January 2021

Development of New Radical-mediated Selective Reactions Promoted by Hypervalent Iodine(III) Reagents.

Chem Rec 2020 Nov 19. Epub 2020 Nov 19.

Graduate School of Pharmaceutical Sciences, Kyoto University Sakyo, Kyoto, 606-8501, Japan.

In this account, we describe our recent developments on the four-types of hypervalent iodine(III)-mediated radical reactions in organic synthesis. Firstly, the activation of aldehydic C-H bonds can be successfully effected with hypervalent iodine(III) reagents, thereby allowing the synthesis of various ketones with high efficiency. Secondly, the site-selective oxidation of unactivated C(sp )-H bonds of hydrocarbon substrates was realized with designer hypervalent iodine(III) reagents. Thirdly, various perfluoroalkyl and α-aminoalkyl radicals can be generated from sodium perfluoroalkanesulfinates and sodium α-aminoalkanesulfinates, respectively, under the influence of hypervalent iodine(III) reagents. Finally, the efficient generation of difluoromethyl radical from hypervalent difluoroacetoxyliodine(III) reagent was realized by photolysis. These four different strategies are illustrated by using various selective radical approaches.
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http://dx.doi.org/10.1002/tcr.202000132DOI Listing
November 2020

Submergence deactivates wound-induced plant defence against herbivores.

Commun Biol 2020 Nov 6;3(1):651. Epub 2020 Nov 6.

Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Korea.

Flooding is a common and critical disaster in agriculture, because it causes defects in plant growth and even crop loss. An increase in herbivore populations is often observed after floods, which leads to additional damage to the plants. Although molecular mechanisms underlying the plant responses to flooding have been identified, how plant defence systems are affected by flooding remains poorly understood. Herein, we show that submergence deactivates wound-induced defence against herbivore attack in Arabidopsis thaliana. Submergence rapidly suppressed the wound-induced expression of jasmonic acid (JA) biosynthesis genes, resulting in reduced JA accumulation. While plants exposed to hypoxia in argon gas exhibited similar reduced wound responses, the inhibitory effects were initiated after short-term submergence without signs for lack of oxygen. Instead, expression of ethylene-responsive genes was increased after short-term submergence. Blocking ethylene signalling by ein2-1 mutation partially restored suppressed expression of several wound-responsive genes by submergence. In addition, submergence rapidly removed active markers of histone modifications at a gene locus involved in JA biosynthesis. Our findings suggest that submergence inactivates defence systems of plants, which would explain the proliferation of herbivores after flooding.
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http://dx.doi.org/10.1038/s42003-020-01376-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7648080PMC
November 2020

Complete genome sequence and genome organization of achyranthes virus A, a novel member of the genus Potyvirus.

Arch Virol 2020 Nov 26;165(11):2695-2698. Epub 2020 Aug 26.

Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea.

The complete genomic sequence of achyranthes virus A (AcVA), from an Achyranthes bidentata Blume plant in South Korea, was determined. The genomic RNA has 9491 nucleotides (nt), excluding the 3'-terminal poly(A) tail and contains an open reading frame typical of members of the genus Potyvirus, family Potyviridae, encoding a large putative polyprotein of 3103 amino acids (aa). Pairwise comparisons showed that the AcVA sequence shares 47.81-57.78% nt sequence identity at the complete genome level, 41.89-56.41% aa sequence identity at the polyprotein level, and 50-63.8% aa sequence identity at the coat protein level with other members of genus Potyvirus. These pairwise comparison values are below the species demarcation cutoff for the family Potyviridae. Our results therefore suggest that this virus should be regarded as a novel member of the genus Potyvirus, tentatively named "achyranthes virus A".
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http://dx.doi.org/10.1007/s00705-020-04778-1DOI Listing
November 2020

Production of Flavonoids in Callus Cultures of Aiton.

Plants (Basel) 2020 May 28;9(6). Epub 2020 May 28.

Plant Systems Engineering Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea.

Flavonoids, including maackiain (Maac) from Aiton roots, have many pharmacological properties, such as antitumor, antimicrobial, and antifungal activities. This research aimed to develop an in vitro plant and callus culture system for for the purpose of generating an alternative production system for enhancing Maac production, as Maac is usually present in very small amounts in roots. We arranged the optimal conditions of different tissues of and supplemented the medium with various plant growth regulators (PGRs). The highest induction and proliferation rates of callus was shown in combination treatments of all concentrations of thidiazuron (TDZ) and picloram. In addition, calli induced with leaf explants cultured on 2.0 mg/L picloram and 0.5 mg/L 6-benzyladenine (BA) in Murashige and Skoog (MS) medium had the highest accumulation of the active metabolite Maac. In vitro shoots were regenerated on medium containing combinations of TDZ and α-Naphthalene acetic acid (NAA). A reliable protocol for the mass production of secondary metabolites using a callus culture of was successfully established.
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http://dx.doi.org/10.3390/plants9060688DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356026PMC
May 2020

Genomic partitioning of growth traits using a high-density single nucleotide polymorphism array in Hanwoo (Korean cattle).

Asian-Australas J Anim Sci 2020 Oct 13;33(10):1558-1565. Epub 2020 Jan 13.

Division of Animal and Dairy Science, Chungnam National University, Daejeon 34134, Korea.

Objective: The objective of this study was to characterize the number of loci affecting growth traits and the distribution of single nucleotide polymorphism (SNP) effects on growth traits, and to understand the genetic architecture for growth traits in Hanwoo (Korean cattle) using genome-wide association study (GWAS), genomic partitioning, and hierarchical Bayesian mixture models.

Methods: GWAS: A single-marker regression-based mixed model was used to test the association between SNPs and causal variants. A genotype relationship matrix was fitted as a random effect in this linear mixed model to correct the genetic structure of a sire family. Genomic restricted maximum likelihood and BayesR: A priori information included setting the fixed additive genetic variance to a pre-specified value; the first mixture component was set to zero, the second to 0.0001×σ_g^2, the third 0.001 × σ_g^2, d the fourth to 0.01 × σ_g^2. BayesR fixed a priori information was not more than 1% of the genetic variance for each of the SNPs affecting the mixed distribution.

Results: The GWAS revealed common genomic regions of 2 Mb on bovine chromosome 14 (BTA14) and 3 had a moderate effect that may contain causal variants for body weight at 6, 12, 18, and 24 months. This genomic region explained approximately 10% of the variance against total additive genetic variance and body weight heritability at 12, 18, and 24 months. BayesR identified the exact genomic region containing causal SNPs on BTA14, 3, and 22. However, the genetic variance explained by each chromosome or SNP was estimated to be very small compared to the total additive genetic variance. Causal SNPs for growth trait on BTA14 explained only 0.04% to 0.5% of the genetic variance.

Conclusion: Segregating mutations have a moderate effect on BTA14, 3, and 19; many other loci with small effects on growth traits at different ages were also identified.
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http://dx.doi.org/10.5713/ajas.19.0699DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7463090PMC
October 2020

OsFKBP20-1b interacts with the splicing factor OsSR45 and participates in the environmental stress response at the post-transcriptional level in rice.

Plant J 2020 06 13;102(5):992-1007. Epub 2020 Feb 13.

Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Korea.

Sessile plants have evolved distinct mechanisms to respond and adapt to adverse environmental conditions through diverse mechanisms including RNA processing. While the role of RNA processing in the stress response is well understood for Arabidopsis thaliana, limited information is available for rice (Oryza sativa). Here, we show that OsFKBP20-1b, belonging to the immunophilin family, interacts with the splicing factor OsSR45 in both nuclear speckles and cytoplasmic foci, and plays an essential role in post-transcriptional regulation of abiotic stress response. The expression of OsFKBP20-1b was highly upregulated under various abiotic stresses. Moreover genetic analysis revealed that OsFKBP20-1b positively affected transcription and pre-mRNA splicing of stress-responsive genes under abiotic stress conditions. In osfkbp20-1b loss-of-function mutants, the expression of stress-responsive genes was downregulated, while that of their splicing variants was increased. Conversely, in plants overexpressing OsFKBP20-1b, the expression of the same stress-responsive genes was strikingly upregulated under abiotic stress. In vivo experiments demonstrated that OsFKBP20-1b directly maintains protein stability of OsSR45 splicing factor. Furthermore, we found that the plant-specific OsFKBP20-1b gene has uniquely evolved as a paralogue only in some Poaceae species. Together, our findings suggest that OsFKBP20-1b-mediated RNA processing contributes to stress adaptation in rice.
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http://dx.doi.org/10.1111/tpj.14682DOI Listing
June 2020

Development of Systems for the Production of Plant-Derived Biopharmaceuticals.

Plants (Basel) 2019 Dec 24;9(1). Epub 2019 Dec 24.

Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea.

Over the last several decades, plants have been developed as a platform for the production of useful recombinant proteins due to a number of advantages, including rapid production and scalability, the ability to produce unique glycoforms, and the intrinsic safety of food crops. The expression methods used to produce target proteins are divided into stable and transient systems depending on applications that use whole plants or minimally processed forms. In the early stages of research, stable expression systems were mostly used; however, in recent years, transient expression systems have been preferred. The production of the plant itself, which produces recombinant proteins, is currently divided into two major approaches, open-field cultivation and closed-indoor systems. The latter encompasses such regimes as greenhouses, vertical farming units, cell bioreactors, and hydroponic systems. Various aspects of each system will be discussed in this review, which focuses mainly on practical examples and commercially feasible approaches.
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http://dx.doi.org/10.3390/plants9010030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7020158PMC
December 2019

Golgi-localized cyclophilin 21 proteins negatively regulate ABA signalling via the peptidyl prolyl isomerase activity during early seedling development.

Plant Mol Biol 2020 Jan 30;102(1-2):19-38. Epub 2019 Nov 30.

Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon, 34141, South Korea.

Key Message: Plant possesses particular Golgi-resident cyclophilin 21 proteins (CYP21s) and the catalytic isomerase activities have a negative effect on ABA signalling gene expression during early seedling development. Cyclophilins (CYPs) are essential for diverse cellular process, as these catalyse a rate-limiting step in protein folding. Although Golgi proteomics in Arabidopsis thaliana suggests the existence of several CYPs in the Golgi apparatus, only one putative Golgi-resident CYP protein has been reported in rice (Oryza sativa L.; OsCYP21-4). Here, we identified the Golgi-resident CYP21 family genes and analysed their molecular characteristics in Arabidopsis and rice. The CYP family genes (CYP21-1, CYP21-2, CYP21-3, and CYP21-4) are plant-specific, and their appearance and copy numbers differ among plant species. CYP21-1 and CYP21-4 are common to all angiosperms, whereas CYP21-2 and CYP21-3 evolved in the Malvidae subclass. Furthermore, all CYP21 proteins localize to cis-Golgi, trans-Golgi or both cis- and trans-Golgi membranes in plant cells. Additionally, based on the structure, enzymatic function, and topological orientation in Golgi membranes, CYP21 proteins are divided into two groups. Genetic analysis revealed that Group I proteins (CYP21-1 and CYP21-2) exhibit peptidyl prolyl cis-trans isomerase (PPIase) activity and regulate seed germination and seedling growth and development by affecting the expression levels of abscisic acid signalling genes. Thus, we identified the Golgi-resident CYPs and demonstrated that their PPIase activities are required for early seedling growth and development in higher plants.
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http://dx.doi.org/10.1007/s11103-019-00928-5DOI Listing
January 2020

Validation Study of SNPs in CAPN1-CAST Genes on the Tenderness of Muscles ( and ) in Hanwoo (Korean Cattle).

Animals (Basel) 2019 Sep 17;9(9). Epub 2019 Sep 17.

Division of Animal and Dairy Science, Chungnam National University, Daejeon 305-764, Korea.

Previous studies demonstrated that polymorphisms in the μ-calpain () and calpastatin () genes had significant effects on meat tenderness in different cattle populations. The aim of this study was to validate the potential association of seven single nucleotide polymorphisms (SNPs) harbored in these two candidate genes with meat tenderness in the (LT) and (SM) muscles. A total of 1000 animals were genotyped using TaqMan SNP genotyping arrays, and the meat tenderness of two muscle (LT and SM at 7 days post-slaughter) was assessed based on Warner-Bratzler WBSF (WBSF) testing. We observed significant associations of the :c.580T>C, :c.658T>C and :c.1985G>C polymorphisms ( < 0.05) with the WBSF values in the LT and SM muscles. Additive effects of the C allele in :c.580T>C and :c.1985G>C were associated with an increase of 0.16 and 0.15 kg, and 0.08 and 0.26 kg WBSF in the LT and SM, respectively; :c.658T>C had negative effects on the WBSFs. Furthermore, six reconstructed haplotypes demonstrated significant associations with WBSF values ( < 0.05). In conclusion, the significant associations identified between the SNPs in , and WBSF values could be utilized in marker-assisted selection programs in order to improve the beef tenderness of Hanwoo cattle.
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http://dx.doi.org/10.3390/ani9090691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770136PMC
September 2019

PIN-mediated polar auxin transport facilitates root-obstacle avoidance.

New Phytol 2020 02 16;225(3):1285-1296. Epub 2019 Aug 16.

Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Korea.

Plants sense mechanical stimuli to recognise nearby obstacles and change their growth patterns to adapt to the surrounding environment. When roots encounter an obstacle, they rapidly bend away from the impenetrable surface and find the edge of the barrier. However, the molecular mechanisms underlying root-obstacle avoidance are largely unknown. Here, we demonstrate that PIN-FORMED (PIN)-mediated polar auxin transport facilitates root bending during obstacle avoidance. We analysed two types of bending after roots touched barriers. In auxin receptor mutants, the rate of root movement during first bending was largely delayed. Gravity-oriented second bending was also disturbed in these mutants. The reporter assays showed that asymmetrical auxin responses occurred in the roots during obstacle avoidance. Pharmacological analysis suggested that polar auxin transport mediates local auxin accumulation. We found that PINs are required for auxin-assisted root bending during obstacle avoidance. We propose that rapid root movement during obstacle avoidance is not just a passive but an active bending completed through polar auxin transport. Our findings suggest that auxin plays a role in thigmotropism during plant-obstacle interactions.
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http://dx.doi.org/10.1111/nph.16076DOI Listing
February 2020

Developmental Programming of Thermonastic Leaf Movement.

Plant Physiol 2019 06 4;180(2):1185-1197. Epub 2019 Apr 4.

Department of Chemistry, Seoul National University, Seoul 08826, Korea

Plants exhibit diverse polar behaviors in response to directional and nondirectional environmental signals, termed tropic and nastic movements, respectively. The ways in which plants incorporate directional information into tropic behaviors is well understood, but it is less well understood how nondirectional stimuli, such as ambient temperatures, specify the polarity of nastic behaviors. Here, we demonstrate that a developmentally programmed polarity of auxin flow underlies thermo-induced leaf hyponasty in Arabidopsis (). In warm environments, PHYTOCHROME-INTERACTING FACTOR4 (PIF4) stimulates auxin production in the leaf. This results in the accumulation of auxin in leaf petioles, where PIF4 directly activates a gene encoding the PINOID (PID) protein kinase. PID is involved in polarization of the auxin transporter PIN-FORMED3 to the outer membranes of petiole cells. Notably, the leaf polarity-determining ASYMMETRIC LEAVES1 (AS1) directs the induction of to occur predominantly in the abaxial petiole region. These observations indicate that the integration of PIF4-mediated auxin biosynthesis and polar transport, and the AS1-mediated developmental shaping of polar auxin flow, coordinate leaf thermonasty, which facilitates leaf cooling in warm environments. We believe that leaf thermonasty is a suitable model system for studying the developmental programming of environmental adaptation in plants.
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http://dx.doi.org/10.1104/pp.19.00139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548248PMC
June 2019

Role of exercise on molecular mechanisms in the regulation of antidepressant effects.

J Exerc Rehabil 2017 Dec 27;13(6):617-620. Epub 2017 Dec 27.

Department of Sport & Health Science, College of Natural Science, Sangmyung University, Seoul, Korea.

Regular exercise reduces depressive-like behavior activation. In this study, we look for exact roles of exercise on molecular and neuronal mechanisms for antidepressant action by studying the hippocampal neuroplasticity and proliferation. Increased hippocampal neurogenesis with exercise has potential significance for depression. Exercise promotes brain health in the molecular levels in the hippocampus and also affects behavior in a similar way to chronic antidepressant treatment. Wingless (Wnt) and frizzled signaling system plays an important role in cell proliferation, growth, and differentiation during development. Our results demonstrate complicated, differential effects of antidepressants on Wnt signaling system, and assume a role for selected signaling molecules in the neurogenic activity of antidepressant care. Our review suggests that exercise may preserve brain function by increasing neurogenesis through activating Wnt signaling pathway in the psychiatric disorders, such as depression.
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http://dx.doi.org/10.12965/jer.1735188.594DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5747194PMC
December 2017

Catalytic enantioselective synthesis of carboxy-substituted 2-isoxazolines by cascade oxa-Michael-cyclization.

Org Biomol Chem 2018 01;16(4):657-664

Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu 41566, Republic of Korea.

An efficient quinidine-based phase-transfer-catalyzed enantioselective cascade oxa-Michael-cyclization reaction of hydroxylamine with various β-carboxy-substituted α,β-unsaturated ketones has been achieved for the preparation of chiral carboxy-substituted 2-isoxazolines. This cascade reaction provided the desired products in good yields (up to 98%) with excellent enantioselectivities (91-96% ee). In addition, the cascade reaction was effectively applied to the first catalytic asymmetric synthesis of the herbicide (S)-methiozolin.
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http://dx.doi.org/10.1039/c7ob02722bDOI Listing
January 2018

ZEITLUPE Contributes to a Thermoresponsive Protein Quality Control System in Arabidopsis.

Plant Cell 2017 Nov 23;29(11):2882-2894. Epub 2017 Oct 23.

Department of Chemistry, Seoul National University, Seoul 08825, Korea

Cellular proteins undergo denaturation and oxidative damage under heat stress, forming insoluble aggregates that are toxic to cells. Plants possess versatile mechanisms to deal with insoluble protein aggregates. Denatured proteins are either renatured to their native conformations or removed from cellular compartments; these processes are often referred to as protein quality control. Heat shock proteins (HSPs) act as molecular chaperones that assist in the renaturation-degradation process. However, how protein aggregates are cleared from cells in plants is largely unknown. Here, we demonstrate that heat-induced protein aggregates are removed by a protein quality control system that includes the ZEITLUPE (ZTL) E3 ubiquitin ligase, a central circadian clock component in ZTL mediates the polyubiquitination of aggregated proteins, which leads to proteasomal degradation and enhances the thermotolerance of plants growing at high temperatures. The ZTL-defective mutant exhibited reduced thermotolerance, which was accompanied by a decline in polyubiquitination but an increase in protein aggregate formation. ZTL and its interacting partner HSP90 were cofractionated with insoluble aggregates under heat stress, indicating that ZTL contributes to the thermoresponsive protein quality control machinery. Notably, the circadian clock was hypersensitive to heat in We propose that ZTL-mediated protein quality control contributes to the thermal stability of the circadian clock.
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http://dx.doi.org/10.1105/tpc.17.00612DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5728135PMC
November 2017

Multiple Routes of Light Signaling during Root Photomorphogenesis.

Trends Plant Sci 2017 09 10;22(9):803-812. Epub 2017 Jul 10.

Department of Chemistry, Seoul National University, Seoul 08826, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea. Electronic address:

Plants dynamically adjust their architecture to optimize growth and performance under fluctuating light environments, a process termed photomorphogenesis. A variety of photomorphogenic responses have been studied extensively in the shoots, where diverse photoreceptors and signaling molecules have been functionally characterized. Notably, accumulating evidence demonstrates that the underground roots also undergo photomorphogenesis, raising the question of how roots perceive and respond to aboveground light. Recent findings indicate that root photomorphogenesis is mediated by multiple signaling routes, including shoot-to-root transmission of mobile signaling molecules, direct sensing of light by the roots, and light channeling through the plant body. In this review we discuss recent advances in how light signals are transmitted to the roots to trigger photomorphogenic responses.
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http://dx.doi.org/10.1016/j.tplants.2017.06.009DOI Listing
September 2017

An FCA-mediated epigenetic route towards thermal adaptation of autotrophic development in plants.

BMB Rep 2017 Jul;50(7):343-344

Department of Chemistry, Seoul National University, and Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea.

Plants are able to recognize even small changes in surrounding temperatures to optimize their growth and development. At warm temperatures, plants exhibit diverse architectural adjustments, including hypocotyl and petiole elongation, leaf hyponasty, and reduced stomatal density. However, it was previously unknown how such warm temperatures affected the early stages of seedling development. In our recent study, we demonstrated that the RNA-binding protein, FCA, is critical for sustaining chlorophyll biosynthesis during early seedling development, which is a prerequisite for autotrophic transition at warm temperatures. FCA plays a dual role in this thermal response. It inhibits the rapid degradation of protochlorophyllide oxidoreductases (PORs) that mediate chlorophyll biosynthesis. In addition, it induces the expression of POR genes at the chromatin level, which contributes to maintaining functional enzyme levels. Our findings provide molecular basis for the thermal adaptation of chlorophyll biosynthesis during the early stages of seedling development in nature. [BMB Reports 2017; 50(7): 343-344].
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5584740PMC
http://dx.doi.org/10.5483/bmbrep.2017.50.7.070DOI Listing
July 2017

HOS1 acts as a key modulator of hypocotyl photomorphogenesis.

Plant Signal Behav 2017 05 20;12(5):e1315497. Epub 2017 Apr 20.

a Department of Chemistry , Seoul National University , Seoul , South Korea.

Plants recognize light as an environmental signal to determine the proper timing of growth and development. In Arabidopsis seedlings, hypocotyl growth is promoted in the dark but suppressed in the light. It is known that the red/far-red light-sensing receptor phytochrome B (phyB) suppresses the function of PHYTOCHROME INTERACTING FACTOR (PIF) transcription factors, which act as photomorphogenic repressors. However, molecular mechanisms underlying the phyB-mediated inhibition of PIF functioning remain unclear. We recently demonstrated that HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1) facilitates the phyB-mediated suppression of PIF4 during the light period to achieve hypocotyl photomorphogenesis. HOS1 inhibits the transcriptional activation activity of PIF4 by forming protein complexes. Notably, phyB-mediated light signals induce HOS1 activity, thus promoting hypocotyl photomorphogenesis. While HOS1 is known to act as an E3 ubiquitin ligase or a chromatin remodeling factor, our data illustrate a novel role of HOS1: it acts as a component of phyB-mediated light signaling in hypocotyl photomorphogenesis.
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http://dx.doi.org/10.1080/15592324.2017.1315497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5501242PMC
May 2017

COP1 conveys warm temperature information to hypocotyl thermomorphogenesis.

New Phytol 2017 Jul 18;215(1):269-280. Epub 2017 Apr 18.

Department of Chemistry, Seoul National University, Seoul, 151-742, Korea.

Plants adjust their architecture to optimize growth and reproductive success under changing climates. Hypocotyl elongation is a pivotal morphogenic trait that is profoundly influenced by light and temperature conditions. While hypocotyl photomorphogenesis has been well characterized at the molecular level, molecular mechanisms underlying hypocotyl thermomorphogenesis remains elusive. Here, we demonstrate that the E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) conveys warm temperature signals to hypocotyl thermomorphogenesis. To investigate the roles of COP1 and its target ELONGATED HYPOCOTYL 5 (HY5) during hypocotyl thermomorphogenesis, we employed Arabidopsis mutants that are defective in their genes. Transgenic plants overexpressing the genes were also produced. We examined hypocotyl growth and thermoresponsive turnover rate of HY5 protein at warm temperatures under both light and dark conditions. Elevated temperatures trigger the nuclear import of COP1, thereby alleviating the suppression of hypocotyl growth by HY5. While the thermal induction of hypocotyl growth is circadian-gated, the degradation of HY5 by COP1 is uncoupled from light responses and timing information. We propose that thermal activation of COP1 enables coincidence between warm temperature signaling and circadian rhythms, which allows plants to gate hypocotyl thermomorphogenesis at the most profitable time at warm temperatures.
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http://dx.doi.org/10.1111/nph.14581DOI Listing
July 2017

Thermo-Induced Maintenance of Photo-oxidoreductases Underlies Plant Autotrophic Development.

Dev Cell 2017 04 6;41(2):170-179.e4. Epub 2017 Apr 6.

Department of Chemistry, Seoul National University, Seoul 151-742, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea. Electronic address:

Chlorophyll biosynthesis enables autotrophic development of developing seedlings. Upon light exposure, the chlorophyll precursor protochlorophyllide produces reactive oxygen species (ROS). Developing seedlings acquire photosynthetic competence through the action of protochlorophyllide oxidoreductases (PORs) that convert protochlorophyllide to chlorophyllide, reducing ROS production that would otherwise induce cellular damage and chlorophyll bleaching. Here, we show that FCA mediates the thermostabilization of PORs to trigger the conversion of protochlorophyllide to chlorophyllide in developing seedlings. FCA also facilitates the thermal induction of POR genes through histone acetylation that promotes the accessibility of RNA polymerases to the gene promoters. The combined action of FCA maintains PORs at warm temperatures, shifting the chlorophyll-ROS balance toward autotrophic development. We propose that the FCA-mediated thermal adaptation of autotrophic development allows developing seedlings to cope with the heat-absorbing soil surface layer under natural conditions. The thermal adaptive mechanism would provide a potential basis for studying crop performance at warm temperatures.
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http://dx.doi.org/10.1016/j.devcel.2017.03.005DOI Listing
April 2017

Underground roots monitor aboveground environment by sensing stem-piped light.

Commun Integr Biol 2016 9;9(6):e1261769. Epub 2016 Dec 9.

Department of Chemistry, Seoul National University, Seoul, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul, Korea.

Light is a critical environmental cue for plant growth and development. Plants actively monitor surrounding environments by sensing changes in light wavelength and intensity. Therefore, plants have evolved a series of photoreceptors to perceive a broad wavelength range of light. Phytochrome photoreceptors sense red and far-red light, which serves as a major photomorphogenic signal in shoot growth and morphogenesis. Notably, plants also express phytochromes in the roots, obscuring whether and how they perceive light in the soil. We have recently demonstrated that plants directly channel light to the roots through plant body to activate root phytochrome B (phyB). Stem light facilitates the nuclear import of phyB in the roots, and the photoactivated phyB triggers the accumulation of the photomorphogenic regulator ELONGATED HYPOCOTYL 5 in modulating root growth and gravitropism. Optical experiments revealed that red to far-red light is efficiently transduced through plant body. Our findings provide physical and molecular evidence, supporting that photoreceptors expressed in the underground roots directly sense light. We propose that the roots are not a passive organ but a central organ that actively monitors changes in the aboveground environment by perceiving light information from the shoots.
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http://dx.doi.org/10.1080/19420889.2016.1261769DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5193042PMC
December 2016

HOS1 Facilitates the Phytochrome B-Mediated Inhibition of PIF4 Function during Hypocotyl Growth in Arabidopsis.

Mol Plant 2017 02 25;10(2):274-284. Epub 2016 Nov 25.

Department of Chemistry, Seoul National University, Seoul 08826, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 08826, Korea. Electronic address:

Upon exposure to light, developing seedlings undergo photomorphogenesis, as illustrated by inhibition of hypocotyl elongation, cotyledon opening, and leaf greening. During hypocotyl photomorphogenesis, light signals are sensed by multiple photoreceptors, among which the red/far-red light-sensing phytochromes have been extensively studied. However, it is not fully understood how the phytochromes modulate hypocotyl growth. Here, we demonstrated that HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES 1 (HOS1), which is known to either act as E3 ubiquitin ligase or affect chromatin organization, inhibits the transcriptional activation activity of PHYTOCHROME INTERACTING FACTOR 4 (PIF4), a key transcription factor that promotes hypocotyl growth. Consistent with the negative regulatory role of HOS1 in hypocotyl growth, HOS1-defective mutants exhibited elongated hypocotyls in the light. Notably, phyB induces HOS1 activity in inhibiting PIF4 function. Taken together, these observations provide a molecular basis for the phyB-mediated suppression of hypocotyl growth in Arabidopsis.
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http://dx.doi.org/10.1016/j.molp.2016.11.009DOI Listing
February 2017

SPL3/4/5 Integrate Developmental Aging and Photoperiodic Signals into the FT-FD Module in Arabidopsis Flowering.

Mol Plant 2016 12 1;9(12):1647-1659. Epub 2016 Nov 1.

Department of Chemistry, Seoul National University, Seoul 151-742, Korea; Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea. Electronic address:

Environmental sensitivity varies across developmental phases in flowering plants. In the juvenile phase, microRNA156 (miR156)-mediated repression of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) transcription factors renders Arabidopsis plants incompetent to floral inductive signals, including long-day (LD) photoperiod. During the vegetative phase transition, which accompanies a reduction of miR156 and a concomitant elevation of its targets, plants acquire reproductive competence such that LD signals promote flowering. However, it remains largely unknown how developmental signals are associated with photoperiodic flowering. Here, we show that SPL3, SPL4, and SPL5 (SPL3/4/5) potentiate the FLOWERING LOCUS T (FT)-FD module in photoperiodic flowering. SPL3/4/5 function as transcriptional activators through the interaction with FD, a basic leucine zipper transcription factor which plays a critical role in photoperiodic flowering. SPL3/4/5 can directly bind to the promoters of APETALA1, LEAFY, and FRUITFULL, thus mediating their activation by the FT-FD complex. Our findings demonstrate that SPL3/4/5 act synergistically with the FT-FD module to induce flowering under LDs, providing a long-sought molecular knob that links developmental aging and photoperiodic flowering.
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http://dx.doi.org/10.1016/j.molp.2016.10.014DOI Listing
December 2016

Stem-piped light activates phytochrome B to trigger light responses in Arabidopsis thaliana roots.

Sci Signal 2016 11 1;9(452):ra106. Epub 2016 Nov 1.

Department of Chemistry, Seoul National University, Seoul 08826, Korea.

The roles of photoreceptors and their associated signaling mechanisms have been extensively studied in plant photomorphogenesis with a major focus on the photoresponses of the shoot system. Accumulating evidence indicates that light also influences root growth and development through the light-induced release of signaling molecules that travel from the shoot to the root. We explored whether aboveground light directly influences the root system of Arabidopsis thaliana Light was efficiently conducted through the stems to the roots, where photoactivated phytochrome B (phyB) triggered expression of ELONGATED HYPOCOTYL 5 (HY5) and accumulation of HY5 protein, a transcription factor that promotes root growth in response to light. Stimulation of HY5 in response to illumination of only the shoot was reduced when root tissues carried a loss-of-function mutation in PHYB, and HY5 mutant roots exhibited alterations in root growth and gravitropism in response to shoot illumination. These findings demonstrate that the underground roots directly sense stem-piped light to monitor the aboveground light environment during plant environmental adaptation.
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http://dx.doi.org/10.1126/scisignal.aaf6530DOI Listing
November 2016

Alternative splicing provides a proactive mechanism for the diurnal CONSTANS dynamics in Arabidopsis photoperiodic flowering.

Plant J 2017 01 5;89(1):128-140. Epub 2016 Dec 5.

Department of Chemistry, Seoul National University, Seoul, 08826, Korea.

The circadian clock control of CONSTANS (CO) transcription and the light-mediated stabilization of its encoded protein coordinately adjust photoperiodic flowering by triggering rhythmic expression of the floral integrator flowering locus T (FT). Diurnal accumulation of CO is modulated sequentially by distinct E3 ubiquitin ligases, allowing peak CO to occur in the late afternoon under long days. Here we show that CO abundance is not simply targeted by E3 enzymes but is also actively self-adjusted through dynamic interactions between two CO isoforms. Alternative splicing of CO produces two protein variants, the full-size COα and the truncated COβ lacking DNA-binding affinity. Notably, COβ, which is resistant to E3 enzymes, induces the interaction of COα with CO-destabilizing E3 enzymes but inhibits the association of COα with CO-stabilizing E3 ligase. These observations demonstrate that CO plays an active role in sustaining its diurnal accumulation dynamics during Arabidopsis photoperiodic flowering.
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http://dx.doi.org/10.1111/tpj.13351DOI Listing
January 2017

Systemic Immunity Requires SnRK2.8-Mediated Nuclear Import of NPR1 in Arabidopsis.

Plant Cell 2015 Dec 15;27(12):3425-38. Epub 2015 Dec 15.

Department of Chemistry, Seoul National University, Seoul 151-742, Korea Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-742, Korea

In plants, necrotic lesions occur at the site of pathogen infection through the hypersensitive response, which is followed by induction of systemic acquired resistance (SAR) in distal tissues. Salicylic acid (SA) induces SAR by activating NONEXPRESSER OF PATHOGENESIS-RELATED GENES1 (NPR1) through an oligomer-to-monomer reaction. However, SA biosynthesis is elevated only slightly in distal tissues during SAR, implying that SA-mediated induction of SAR requires additional factors. Here, we demonstrated that SA-independent systemic signals induce a gene encoding SNF1-RELATED PROTEIN KINASE 2.8 (SnRK2.8), which phosphorylates NPR1 during SAR. The SnRK2.8-mediated phosphorylation of NPR1 is necessary for its nuclear import. Notably, although SnRK2.8 transcription and SnRK2.8 activation are independent of SA signaling, the SnRK2.8-mediated induction of SAR requires SA. Together with the SA-mediated monomerization of NPR1, these observations indicate that SA signals and SnRK2.8-mediated phosphorylation coordinately function to activate NPR1 via a dual-step process in developing systemic immunity in Arabidopsis thaliana.
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http://dx.doi.org/10.1105/tpc.15.00371DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4707448PMC
December 2015

Enantioselective Phase-Transfer-Catalyzed Synthesis of Chiral N-Substituted 3,3-Dinitroazetidines by Aza-Michael Reaction.

J Org Chem 2015 Nov 11;80(22):11435-40. Epub 2015 Nov 11.

Department of Chemistry, Kyungpook National University , Daegu 702-701, Republic of Korea.

An efficient and highly enantioselective phase-transfer-catalyzed aza-Michael reaction of 3,3-dinitroazetidine, as N-centered nucleophile, to α,β-unsaturated ketones has been achieved using a quinidine-based phase-transfer catalyst (0.5-1 mol %), providing chiral N-substituted 3,3-dinitroazetidines in good yields (up to 99%) and excellent enantioselectivities (90-95% ee). This is the first example of the use of azetidines as N-centered nucleophiles in catalytic enantioselective aza-Michael reactions.
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http://dx.doi.org/10.1021/acs.joc.5b02124DOI Listing
November 2015

A two-photon fluorescent probe for lysosomal zinc ions.

Chem Commun (Camb) 2016 Jan;52(1):124-7

Department of Chemistry, POSTECH, Pohang 790-784, Republic of Korea.

The selective detection of zinc ions in lysosomes over that in cytosol is achieved with a fluorescent probe, which enabled the fluorescence imaging of endogenous zinc ions in lysosomes of NIH 3T3 cells as well as mouse hippocampal tissues by two-photon microscopy under excitation at 900 nm.
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http://dx.doi.org/10.1039/c5cc06976aDOI Listing
January 2016