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Microbial electrosynthesis (MES) is a promising technology platform for the production of chemicals and fuels from CO2 and external conducting materials (i.e., electrodes). In this system, electroactive microorganisms, called electrotrophs, serve as biocatalysts for cathodic reaction. While several CO2-fixing microorganisms can reduce CO2 to a variety of organic compounds by utilizing electricity as reducing energy, direct extracellular electron uptake is indispensable to achieve highly energy-efficient reaction. In the work reported here, Rhodobacter sphaeroides, a CO2-fixing chemoautotroph and a potential electroactive bacterium, was adopted to perform a cathodic CO2 reduction reaction via MES. To promote direct electron uptake, the graphite felt cathode was modified with a combination of chitosan and carbodiimide compound. Robust biofilm formation promoted by amide functionality between R. sphaeroides and a graphite felt cathode showed significantly higher faradaic efficiency (98.0%) for coulomb to biomass and succinic acid production than those of the bare (34%) and chitosan-modified graphite cathode (77.8%), respectively. The results suggest that cathode modification using a chitosan/carbodiimide composite may facilitate electron utilization by improving direct contact between an electrode and R. sphaeroides.
Hana Nur Fitriana; Jiye Lee; Sangmin Lee; Myounghoon Moon; Yu Rim Lee; You-Kwan Oh; Myeonghwa Park; Jin-Suk Lee; Jinju Song; Soo Youn Lee. Surface Modification of a Graphite Felt Cathode with Amide-Coupling Enhances the Electron Uptake of Rhodobacter sphaeroides. Applied Sciences 2021, 11, 7585 .
AMA StyleHana Nur Fitriana, Jiye Lee, Sangmin Lee, Myounghoon Moon, Yu Rim Lee, You-Kwan Oh, Myeonghwa Park, Jin-Suk Lee, Jinju Song, Soo Youn Lee. Surface Modification of a Graphite Felt Cathode with Amide-Coupling Enhances the Electron Uptake of Rhodobacter sphaeroides. Applied Sciences. 2021; 11 (16):7585.
Chicago/Turabian StyleHana Nur Fitriana; Jiye Lee; Sangmin Lee; Myounghoon Moon; Yu Rim Lee; You-Kwan Oh; Myeonghwa Park; Jin-Suk Lee; Jinju Song; Soo Youn Lee. 2021. "Surface Modification of a Graphite Felt Cathode with Amide-Coupling Enhances the Electron Uptake of Rhodobacter sphaeroides." Applied Sciences 11, no. 16: 7585.
In the recent climate change regime, industrial demand for renewable materials to replace petroleum-derived polymers continues to rise. Of particular interest is polyhydroxybutyrate (PHB) as a substitute for polypropylene. Accumulating evidence indicates that PHB is highly produced as a carbon storage material in various microorganisms. The effects of growth conditions on PHB production have been widely studied in chemolithotrophs, particularly in Rhodobacter. However, the results on PHB production in Rhodobacter have been somewhat inconsistent due to different strains and experimental conditions, and it is currently unclear how diverse environmental factors are linked with PHB production. Here, we report optimized growth conditions for PHB production and show that the growth conditions are closely related to reactive oxygen species (ROS) regulation. PHB accumulates in cells up to approximately 50% at the highest level under dark-aerobic conditions as opposed to light aerobic/anaerobic conditions. According to the time-course, PHB contents increased at 48 h and then gradually decreased. When observing the effect of temperature and medium composition on PHB production, 30 °C and a carbon/nitrogen ratio of 9:1 or more were found to be most effective. Among PHB biosynthetic genes, PhaA and PhaB are highly correlated with PHB production, whereas PhaC and PhaZ showed little change in overall expression levels. We found that, while the amount of hydrogen peroxide in cells under dark conditions was relatively low compared to the light conditions, peroxidase activities and expression levels of antioxidant-related genes were high. These observations suggest optimal culture conditions for growth and PHB production and the importance of ROS-scavenging signaling with regard to PHB production.
Yu Rim Lee; Hana Nur Fitriana; Soo Youn Lee; Min-Sik Kim; Myounghoon Moon; Won-Heong Lee; Jin-Suk Lee; Sangmin Lee. Molecular Profiling and Optimization Studies for Growth and PHB Production Conditions in Rhodobacter sphaeroides. Energies 2020, 13, 6471 .
AMA StyleYu Rim Lee, Hana Nur Fitriana, Soo Youn Lee, Min-Sik Kim, Myounghoon Moon, Won-Heong Lee, Jin-Suk Lee, Sangmin Lee. Molecular Profiling and Optimization Studies for Growth and PHB Production Conditions in Rhodobacter sphaeroides. Energies. 2020; 13 (23):6471.
Chicago/Turabian StyleYu Rim Lee; Hana Nur Fitriana; Soo Youn Lee; Min-Sik Kim; Myounghoon Moon; Won-Heong Lee; Jin-Suk Lee; Sangmin Lee. 2020. "Molecular Profiling and Optimization Studies for Growth and PHB Production Conditions in Rhodobacter sphaeroides." Energies 13, no. 23: 6471.
The electrochemical conversion of CO2 can include renewable surplus electricity storage and CO2 utilisation. This review focuses on the microbial CO2 electrobiorefinery based on microbial electrosynthesis (MES) which merges electrochemical and microbial conversion to produce biofuels and higher-value chemicals. In this review, recent developments are discussed about bioelectrochemical conversion of CO2 into biofuels and chemicals in MES via microbial CO2-fixation and electricity utilisation reactions. In addition, this review examines technical approaches to overcome the current limitations of MES including the following: engineering of the biocathode, application of electron mediators, and reactor optimisation, among others. An in-depth discussion of strategies for the CO2 electrobiorefinery is presented, including the integration of the biocathode with inorganic catalysts, screening of novel electroactive microorganisms, and metabolic engineering to improve target productivity from CO2.
Soo Youn Lee; You-Kwan Oh; Sangmin Lee; Hana Nur Fitriana; Myounghoon Moon; Min-Sik Kim; Jiye Lee; Kyoungseon Min; Gwon Woo Park; Joon-Pyo Lee; Jin-Suk Lee. Recent developments and key barriers to microbial CO2 electrobiorefinery. Bioresource Technology 2020, 320, 124350 .
AMA StyleSoo Youn Lee, You-Kwan Oh, Sangmin Lee, Hana Nur Fitriana, Myounghoon Moon, Min-Sik Kim, Jiye Lee, Kyoungseon Min, Gwon Woo Park, Joon-Pyo Lee, Jin-Suk Lee. Recent developments and key barriers to microbial CO2 electrobiorefinery. Bioresource Technology. 2020; 320 ():124350.
Chicago/Turabian StyleSoo Youn Lee; You-Kwan Oh; Sangmin Lee; Hana Nur Fitriana; Myounghoon Moon; Min-Sik Kim; Jiye Lee; Kyoungseon Min; Gwon Woo Park; Joon-Pyo Lee; Jin-Suk Lee. 2020. "Recent developments and key barriers to microbial CO2 electrobiorefinery." Bioresource Technology 320, no. : 124350.
To alleviate carbon dioxide (CO2) emission, alternative approaches have been considered, such as employing microorganisms capable of CO2-fixation using their own metabolic pathways.
Soo Youn Lee; Young Su Kim; Woo-Ri Shin; Jaeyoung Yu; Jiye Lee; Sangmin Lee; Yang-Hoon Kim; Jiho Min. Non-photosynthetic CO2bio-mitigation byEscherichia coliharbouring CBB genes. Green Chemistry 2020, 22, 6889 -6896.
AMA StyleSoo Youn Lee, Young Su Kim, Woo-Ri Shin, Jaeyoung Yu, Jiye Lee, Sangmin Lee, Yang-Hoon Kim, Jiho Min. Non-photosynthetic CO2bio-mitigation byEscherichia coliharbouring CBB genes. Green Chemistry. 2020; 22 (20):6889-6896.
Chicago/Turabian StyleSoo Youn Lee; Young Su Kim; Woo-Ri Shin; Jaeyoung Yu; Jiye Lee; Sangmin Lee; Yang-Hoon Kim; Jiho Min. 2020. "Non-photosynthetic CO2bio-mitigation byEscherichia coliharbouring CBB genes." Green Chemistry 22, no. 20: 6889-6896.
This work studied Gram-positive and weak electricigen Corynebacterium glutamicum for its ability to transfer electrons and to produce bioelectricity in microbial fuel cells (MFCs). The electrochemical and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) results revealed that C. glutamicum had the potential to mediate electron transfer to an electrode by emitting its own extracellular electron shuttles such as flavins. To enhance the current collection from C. glutamicum, a carbon cloth anode was modified with ferrocene-branched chitosan hydrogel (redox-hydrogel). The maximum current density of the ferrocene-branched chitosan redox hydrogel anode with C. glutamicum was drastically increased to 120 µA cm−2 relative to a bare carbon cloth electrode with C. glutamicum (261 nA cm−2). The power density and polarization curves for the MFC operation with the redox-hydrogel-modified anode showed that C. glutamicum effectively generated bioelectricity by means of the redox-hydrogel anode. The results suggest that, in such an electro-fermentation process, ferrocene-branched chitosan hydrogel grafted onto an anode surface would also facilitate both electron transfer from C. glutamicum to the anode and bioelectricity generation.
Soo Youn Lee; Jiho Min; Sangmin Lee; Hana Nur Fitriana; Min-Sik Kim; Gwon Woo Park; Jin-Suk Lee. Bioelectricity Generation by Corynebacterium glutamicum with Redox-Hydrogel-Modified Carbon Electrode. Applied Sciences 2019, 9, 4251 .
AMA StyleSoo Youn Lee, Jiho Min, Sangmin Lee, Hana Nur Fitriana, Min-Sik Kim, Gwon Woo Park, Jin-Suk Lee. Bioelectricity Generation by Corynebacterium glutamicum with Redox-Hydrogel-Modified Carbon Electrode. Applied Sciences. 2019; 9 (20):4251.
Chicago/Turabian StyleSoo Youn Lee; Jiho Min; Sangmin Lee; Hana Nur Fitriana; Min-Sik Kim; Gwon Woo Park; Jin-Suk Lee. 2019. "Bioelectricity Generation by Corynebacterium glutamicum with Redox-Hydrogel-Modified Carbon Electrode." Applied Sciences 9, no. 20: 4251.
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.
Ju-Heon Kim; Hyo-Jun Lee; Jae-Hoon Jung; Sangmin Lee; Chung-Mo Park. HOS1 Facilitates the Phytochrome B-Mediated Inhibition of PIF4 Function during Hypocotyl Growth in Arabidopsis. Molecular Plant 2017, 10, 274 -284.
AMA StyleJu-Heon Kim, Hyo-Jun Lee, Jae-Hoon Jung, Sangmin Lee, Chung-Mo Park. HOS1 Facilitates the Phytochrome B-Mediated Inhibition of PIF4 Function during Hypocotyl Growth in Arabidopsis. Molecular Plant. 2017; 10 (2):274-284.
Chicago/Turabian StyleJu-Heon Kim; Hyo-Jun Lee; Jae-Hoon Jung; Sangmin Lee; Chung-Mo Park. 2017. "HOS1 Facilitates the Phytochrome B-Mediated Inhibition of PIF4 Function during Hypocotyl Growth in Arabidopsis." Molecular Plant 10, no. 2: 274-284.
Isoprene is a naturally produced hydrocarbon emitted into the atmosphere by green plants. It is also a constituent of synthetic rubber and a potential biofuel. Microbial production of isoprene can become a sustainable alternative to the prevailing chemical production of isoprene from petroleum. In this work, sequence homology searches were conducted to find novel isoprene synthases. Candidate sequences were functionally expressed in Escherichia coli and the desired enzymes were identified based on an isoprene production assay. The activity of three enzymes was shown for the first time: expression of the candidate genes from Ipomoea batatas, Mangifera indica, and Elaeocarpus photiniifolius resulted in isoprene formation. The Ipomoea batatas isoprene synthase produced the highest amounts of isoprene in all experiments, exceeding the isoprene levels obtained by the previously known Populus alba and Pueraria montana isoprene synthases that were studied in parallel as controls.
Marja Ilmén; Merja Oja; Anne Huuskonen; Sangmin Lee; Laura Ruohonen; Simon Jung. Identification of novel isoprene synthases through genome mining and expression in Escherichia coli. Metabolic Engineering 2015, 31, 153 -162.
AMA StyleMarja Ilmén, Merja Oja, Anne Huuskonen, Sangmin Lee, Laura Ruohonen, Simon Jung. Identification of novel isoprene synthases through genome mining and expression in Escherichia coli. Metabolic Engineering. 2015; 31 ():153-162.
Chicago/Turabian StyleMarja Ilmén; Merja Oja; Anne Huuskonen; Sangmin Lee; Laura Ruohonen; Simon Jung. 2015. "Identification of novel isoprene synthases through genome mining and expression in Escherichia coli." Metabolic Engineering 31, no. : 153-162.
Global warming is predicted to profoundly affect plant distribution and crop yield in the near future. Higher ambient temperature can influence diverse aspects of plant growth and development. In Arabidopsis, the basic helix-loop-helix transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) regulates temperature-induced adaptive responses by modulating auxin biosynthesis. At high temperature, PIF4 directly activates expression of YUCCA8 (YUC8), a gene encoding an auxin biosynthetic enzyme, resulting in auxin accumulation. Here we demonstrate that the RNA-binding protein FCA attenuates PIF4 activity by inducing its dissociation from the YUC8 promoter at high temperature. At 28 °C, auxin content is elevated in FCA-deficient mutants that exhibit elongated stems but reduced in FCA-overexpressing plants that exhibit reduced stem growth. We propose that the FCA-mediated regulation of YUC8 expression tunes down PIF4-induced architectural changes to achieve thermal adaptation of stem growth at high ambient temperature.
Hyo-Jun Lee; Jae-Hoon Jung; Lucas Cortes Llorca; Sang-Gyu Kim; Sangmin Lee; Ian Baldwin; Chung-Mo Park. FCA mediates thermal adaptation of stem growth by attenuating auxin action in Arabidopsis. Nature Communications 2014, 5, 5473 .
AMA StyleHyo-Jun Lee, Jae-Hoon Jung, Lucas Cortes Llorca, Sang-Gyu Kim, Sangmin Lee, Ian Baldwin, Chung-Mo Park. FCA mediates thermal adaptation of stem growth by attenuating auxin action in Arabidopsis. Nature Communications. 2014; 5 (1):5473.
Chicago/Turabian StyleHyo-Jun Lee; Jae-Hoon Jung; Lucas Cortes Llorca; Sang-Gyu Kim; Sangmin Lee; Ian Baldwin; Chung-Mo Park. 2014. "FCA mediates thermal adaptation of stem growth by attenuating auxin action in Arabidopsis." Nature Communications 5, no. 1: 5473.
Programmed cell death (PCD) is an integral component of plant development and adaptation under adverse environmental conditions. Reactive oxygen species (ROS) are one of the most important players that trigger PCD in plants, and ROS-generating machinery is activated in plant cells undergoing PCD. The membrane-bound NAC transcription factor NTL4 has recently been proven to facilitate ROS production in response to drought stress in Arabidopsis. In this work, we show that NTL4 participates in a positive feedback loop that bursts ROS accumulation to modulate PCD under heat stress conditions. Heat stress induces NTL4 gene transcription and NTL4 protein processing. The level of hydrogen peroxide (H2O2) was elevated in 35S:4ΔC transgenic plants that overexpress a transcriptionally active nuclear NTL4 form but significantly reduced in NTL4-deficient ntl4 mutants under heat stress conditions. In addition, heat stress-induced cell death was accelerated in the 35S:4ΔC transgenic plants but decreased in the ntl4 mutants. Notably, H2O2 triggers NTL4 gene transcription and NTL4 protein processing under heat stress conditions. On the basis of these findings, we conclude that NTL4 modulates PCD through a ROS-mediated positive feedback control under heat stress conditions, possibly providing an adaptation strategy by which plants ensure their survival under extreme heat stress conditions.
Sangmin Lee; Hyo-Jun Lee; Sung Un Huh; Kyung-Hee Paek; Jun-Ho Ha; Chung-Mo Park. The Arabidopsis NAC transcription factor NTL4 participates in a positive feedback loop that induces programmed cell death under heat stress conditions. Plant Science 2014, 227, 76 -83.
AMA StyleSangmin Lee, Hyo-Jun Lee, Sung Un Huh, Kyung-Hee Paek, Jun-Ho Ha, Chung-Mo Park. The Arabidopsis NAC transcription factor NTL4 participates in a positive feedback loop that induces programmed cell death under heat stress conditions. Plant Science. 2014; 227 ():76-83.
Chicago/Turabian StyleSangmin Lee; Hyo-Jun Lee; Sung Un Huh; Kyung-Hee Paek; Jun-Ho Ha; Chung-Mo Park. 2014. "The Arabidopsis NAC transcription factor NTL4 participates in a positive feedback loop that induces programmed cell death under heat stress conditions." Plant Science 227, no. : 76-83.
Heat stress affects various aspects of plant growth and development by generating reactive oxygen species (ROS) which cause oxidative damage to cellular components. However, the mechanisms by which plants cope with ROS accumulation during their thermotolerance response remain largely unknown. Here, we demonstrate that the RNA-binding protein FCA, a key component of flowering pathways in Arabidopsis thaliana, is required for the acquisition of thermotolerance. Transgenic plants overexpressing the FCA gene (35S:FCA) were resistant to heat stress; the FCA-defective fca-9 mutant was sensitive to heat stress, consistent with induction of the FCA gene by heat. Furthermore, total antioxidant capacity was higher in the 35S:FCA transgenic plants but lower in the fca-9 mutant compared with wild-type controls. FCA interacts with the ABA-INSENSITIVE 5 (ABI5) transcription factor, which regulates the expression of genes encoding antioxidants, including 1-CYSTEINE PEROXIREDOXIN 1 (PER1). We found that FCA is needed for proper expression of the PER1 gene by ABI5. Our observations indicate that FCA plays a role in the induction of thermotolerance by triggering antioxidant accumulation under heat stress conditions, thus providing a novel role for FCA in heat stress responses in plants.
Sangmin Lee; Hyo‐Jun Lee; Jae‐Hoon Jung; Chung‐Mo Park. The A rabidopsis thaliana RNA ‐binding protein FCA regulates thermotolerance by modulating the detoxification of reactive oxygen species. New Phytologist 2014, 205, 555 -569.
AMA StyleSangmin Lee, Hyo‐Jun Lee, Jae‐Hoon Jung, Chung‐Mo Park. The A rabidopsis thaliana RNA ‐binding protein FCA regulates thermotolerance by modulating the detoxification of reactive oxygen species. New Phytologist. 2014; 205 (2):555-569.
Chicago/Turabian StyleSangmin Lee; Hyo‐Jun Lee; Jae‐Hoon Jung; Chung‐Mo Park. 2014. "The A rabidopsis thaliana RNA ‐binding protein FCA regulates thermotolerance by modulating the detoxification of reactive oxygen species." New Phytologist 205, no. 2: 555-569.
MicroRNA172 (miR172) regulates phase transition and floral patterning in Arabidopsis by repressing targets that encode the APETALA2 (AP2) and AP2-like transcription factors. The miR172-mediated repression of the AP2 gene restricts AGAMOUS (AG) expression. In addition, most miR172 targets, including AP2, redundantly act as floral repressors, and the overexpression of the target genes causes delayed flowering. However, how miR172 targets other than AP2 regulate both of the developmental processes remains unclear. Here, we demonstrate that miR172-mediated repression of the TARGET OF EAT 3 (TOE3) gene is critical for floral patterning in Arabidopsis. Transgenic plants that overexpress a miR172-resistant TOE3 gene (rTOE3-ox) exhibit indeterminate flowers with numerous stamens and carpelloid organs, which is consistent with previous observations in transgenic plants that overexpress a miR172-resistant AP2 gene. TOE3 binds to the second intron of the AG gene. Accordingly, AG expression is significantly reduced in rTOE3-ox plants. TOE3 also interacts with AP2 in the nucleus. Given the major role of AP2 in floral patterning, miR172 likely regulates TOE3 in floral patterning, at least in part via AP2. In addition, a miR156 target SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 3 directly activates TOE3 expression, revealing a novel signaling interaction between miR156 and miR172 in floral patterning.
Jae-Hoon Jung; Sangmin Lee; Ju Yun; Minyoung Lee; Chung-Mo Park. The miR172 target TOE3 represses AGAMOUS expression during Arabidopsis floral patterning. Plant Science 2014, 215-216, 29 -38.
AMA StyleJae-Hoon Jung, Sangmin Lee, Ju Yun, Minyoung Lee, Chung-Mo Park. The miR172 target TOE3 represses AGAMOUS expression during Arabidopsis floral patterning. Plant Science. 2014; 215-216 ():29-38.
Chicago/Turabian StyleJae-Hoon Jung; Sangmin Lee; Ju Yun; Minyoung Lee; Chung-Mo Park. 2014. "The miR172 target TOE3 represses AGAMOUS expression during Arabidopsis floral patterning." Plant Science 215-216, no. : 29-38.
Adverse environmental conditions severely influence various aspects of plant growth and developmental processes, causing worldwide reduction of crop yields. The C-repeat binding factors (CBFs) are critical transcription factors constituting the gene regulatory network that mediates the acclimation process to low temperatures. They regulate a large number of cold-responsive genes, including COLD-REGULATED (COR) genes, via the CBF-COR regulon. Recent studies have shown that the CBF transcription factors also play a role in plant responses to drought and salt stresses. Putative CBF gene homologues and their downstream genes are also present in the genome of Brachypodium distachyon, which is perceived as a monocot model in recent years. However, they have not been functionally characterized at the molecular level. Three CBF genes that are responsive to cold were identified from Brachypodium, designated BdCBF1, BdCBF2, and BdCBF3, and they were functionally characterized by molecular biological and transgenic approaches in Brachypodium and Arabidopsis thaliana. Our results demonstrate that the BdCBF genes contribute to the tolerance response of Brachypodium to cold, drought, and salt stresses by regulating downstream targets, such as DEHYDRIN5.1 (Dhn5.1) and COR genes. The BdCBF genes are induced under the environmental stress conditions. The BdCBF proteins possess transcriptional activation activity and bind directly to the promoters of the target genes. Transgenic Brachypodium plants overexpressing the BdCBF genes exhibited enhanced resistance to drought and salt stresses as well as low temperatures, and accordingly endogenous contents of proline and soluble sugars were significantly elevated in the transgenic plants. The BdCBF transcription factors are also functional in the heterologous system Arabidopsis. Transgenic Arabidopsis plants overexpressing the BdCBF genes were also tolerant to freezing, drought, and salt stresses, and a set of stress-responsive genes was upregulated in the transgenic Arabidopsis plants. Taken together, our results strongly support that the BdCBF transcription factors are key regulators of cold stress responses in Brachypodium and the CBF-mediated cold stress signaling pathway is conserved in this plant species. We believe that this study would confer great impact on stress biology in monocot species and could be applied to engineer abiotic stress tolerance of bioenergy grass species.
Jae Yong Ryu; Shin-Young Hong; Sin-Hye Jo; Je-Chang Woo; Sangmin Lee; Chung-Mo Park. Molecular and functional characterization of cold-responsive C-repeat binding factors from Brachypodium distachyon. BMC Plant Biology 2014, 14, 15 -15.
AMA StyleJae Yong Ryu, Shin-Young Hong, Sin-Hye Jo, Je-Chang Woo, Sangmin Lee, Chung-Mo Park. Molecular and functional characterization of cold-responsive C-repeat binding factors from Brachypodium distachyon. BMC Plant Biology. 2014; 14 (1):15-15.
Chicago/Turabian StyleJae Yong Ryu; Shin-Young Hong; Sin-Hye Jo; Je-Chang Woo; Sangmin Lee; Chung-Mo Park. 2014. "Molecular and functional characterization of cold-responsive C-repeat binding factors from Brachypodium distachyon." BMC Plant Biology 14, no. 1: 15-15.
Exposure to short-term cold stress delays flowering by activating the floral repressor FLOWERING LOCUS C (FLC) in Arabidopsis thaliana. The cold signaling attenuator HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1 (HOS1) negatively regulates cold responses. Notably, HOS1-deficient mutants exhibit early flowering, and FLC expression is suppressed in the mutants. However, it remains unknown how HOS1 regulates FLC expression. Here, we show that HOS1 induces FLC expression by antagonizing the actions of FVE and its interacting partner histone deacetylase 6 (HDA6) under short-term cold stress. HOS1 binds to FLC chromatin in an FVE-dependent manner, and FVE is essential for the HOS1-mediated activation of FLC transcription. HOS1 also interacts with HDA6 and inhibits the binding of HDA6 to FLC chromatin. Intermittent cold treatments induce FLC expression by activating HOS1, which attenuates the activity of HDA6 in silencing FLC chromatin, and the effects of intermittent cold are diminished in hos1 and fve mutants. These observations indicate that HOS1 acts as a chromatin remodeling factor for FLC regulation under short-term cold stress.
Jae-Hoon Jung; Ju-Hyung Park; Sangmin Lee; Taiko Kim To; Jong-Myong Kim; Motoaki Seki; Chung-Mo Park. The Cold Signaling Attenuator HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1 Activates FLOWERING LOCUS C Transcription via Chromatin Remodeling under Short-Term Cold Stress in Arabidopsis. The Plant Cell 2013, 25, 4378 -4390.
AMA StyleJae-Hoon Jung, Ju-Hyung Park, Sangmin Lee, Taiko Kim To, Jong-Myong Kim, Motoaki Seki, Chung-Mo Park. The Cold Signaling Attenuator HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1 Activates FLOWERING LOCUS C Transcription via Chromatin Remodeling under Short-Term Cold Stress in Arabidopsis. The Plant Cell. 2013; 25 (11):4378-4390.
Chicago/Turabian StyleJae-Hoon Jung; Ju-Hyung Park; Sangmin Lee; Taiko Kim To; Jong-Myong Kim; Motoaki Seki; Chung-Mo Park. 2013. "The Cold Signaling Attenuator HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1 Activates FLOWERING LOCUS C Transcription via Chromatin Remodeling under Short-Term Cold Stress in Arabidopsis." The Plant Cell 25, no. 11: 4378-4390.
Reactive oxygen species (ROS) are produced when plants are exposed to environmental stresses, such as drought and heat conditions. Oxidative stress imposed by ROS under drought conditions profoundly affects plant growth and development. However, ROS production and scavenging mechanisms under adverse environmental conditions are largely unknown. We have recently reported that a NAM/ATAF1/2/CUC2 (NAC) transcription factor NTL4 is required for generation of ROS under drought conditions in Arabidopsis. 35S:4ΔC transgenic plants overexpressing a truncated NTL4 form (4ΔC) lacking the C‑terminal transmembrane (TM) motif were hypersensitive to drought stress, and ROS accumulated to a high level in the transgenic plants. In contrast, NTL4-deficient ntl4 mutants were less sensitive to drought stress and contained reduced levels of ROS. Furthermore, the plasma membrane-associated NTL4 transcription factor is proteolytically activated by treatments with drought and abscisic acid (ABA) and nuclear-localized, where it induces expression of NADPH oxidase genes involved in ROS biosynthesis. Notably, the 35S:4ΔC transgenic plants showed accelerated leaf senescence and cell death under drought conditions. Taken together, these observations indicate that NTL4 regulation of ROS generation underlies the drought-induced leaf senescence.
Sangmin Lee; Chung-Mo Park. Regulation of reactive oxygen species generation under drought conditions in Arabidopsis. Plant Signaling & Behavior 2012, 7, 599 -601.
AMA StyleSangmin Lee, Chung-Mo Park. Regulation of reactive oxygen species generation under drought conditions in Arabidopsis. Plant Signaling & Behavior. 2012; 7 (6):599-601.
Chicago/Turabian StyleSangmin Lee; Chung-Mo Park. 2012. "Regulation of reactive oxygen species generation under drought conditions in Arabidopsis." Plant Signaling & Behavior 7, no. 6: 599-601.
Reactive oxygen species (ROS) are produced in plant cells primarily as by‐products of aerobic energy metabolism. They are also generated during plant adaptation responses to environmental stresses, such as drought and high salinity. Therefore, plants have evolved ROS‐detoxifying enzymes and antioxidants to cope with ROS accumulation. However, if stress conditions are prolonged, the level of ROS will surpass the capacity of the detoxifying machinery, causing oxidative damage to cellular constituents. It is known that ROS act in abscisic acid‐mediated stress responses to sustain plant survival under adverse growth conditions. However, it is largely unknown how ROS metabolism is linked to stress responses. Here, we show that a drought‐responsive NAC transcription factor NTL4 promotes ROS production by binding directly to the promoters of genes encoding ROS biosynthetic enzymes during drought‐induced leaf senescence. Leaf senescence was accelerated in 35S:4ΔC transgenic plants over‐expressing an active form of NTL4 under drought conditions. The 35S:4ΔC transgenic plants were hypersensitive to drought, and ROS accumulated in the leaves. In contrast, ROS levels were reduced in NTL4‐deficient ntl4 mutants, which exhibited delayed leaf senescence and enhanced drought resistance. These observations indicate that NTL4 acts as a molecular switch that couples ROS metabolism to drought‐induced leaf senescence in Arabidopsis.
Sangmin Lee; Pil Joon Seo; Hyo-Jun Lee; Chung-Mo Park. A NAC transcription factor NTL4 promotes reactive oxygen species production during drought-induced leaf senescence in Arabidopsis. The Plant Journal 2012, 70, 831 -844.
AMA StyleSangmin Lee, Pil Joon Seo, Hyo-Jun Lee, Chung-Mo Park. A NAC transcription factor NTL4 promotes reactive oxygen species production during drought-induced leaf senescence in Arabidopsis. The Plant Journal. 2012; 70 (5):831-844.
Chicago/Turabian StyleSangmin Lee; Pil Joon Seo; Hyo-Jun Lee; Chung-Mo Park. 2012. "A NAC transcription factor NTL4 promotes reactive oxygen species production during drought-induced leaf senescence in Arabidopsis." The Plant Journal 70, no. 5: 831-844.
Potential roles of salicylic acid (SA) on seed germination have been explored in many plant species. However, it is still controversial how SA regulates seed germination, mainly because the results have been somewhat variable, depending on plant genotypes used and experimental conditions employed. We found that SA promotes seed germination under high salinity in Arabidopsis. Seed germination of the sid2 mutant, which has a defect in SA biosynthesis, is hypersensitive to high salinity, but the inhibitory effects are reduced in the presence of physiological concentrations of SA. Abiotic stresses, including high salinity, impose oxidative stress on plants. Endogenous contents of H(2)O(2) are higher in the sid2 mutant seeds. However, exogenous application of SA reduces endogenous level of reactive oxygen species (ROS), indicating that SA is involved in plant responses to ROS-mediated damage under abiotic stress conditions. Gibberellic acid (GA), a plant hormone closely associated with seed germination, also reverses the inhibitory effects of high salinity on seed germination and seedling establishment. Under high salinity, GA stimulates SA biosynthesis by inducing the SID2 gene. Notably, SA also induces genes encoding GA biosynthetic enzymes. These observations indicate that SA promotes seed germination under high salinity by modulating antioxidant activity through signaling crosstalks with GA.
Sangmin Lee; Chung-Mo Park. Modulation of reactive oxygen species by salicylic acid in Arabidopsis seed germination under high salinity. Plant Signaling & Behavior 2010, 5, 1534 -1536.
AMA StyleSangmin Lee, Chung-Mo Park. Modulation of reactive oxygen species by salicylic acid in Arabidopsis seed germination under high salinity. Plant Signaling & Behavior. 2010; 5 (12):1534-1536.
Chicago/Turabian StyleSangmin Lee; Chung-Mo Park. 2010. "Modulation of reactive oxygen species by salicylic acid in Arabidopsis seed germination under high salinity." Plant Signaling & Behavior 5, no. 12: 1534-1536.
The tapetum is a layer of cells covering the inner surface of pollen sac wall. It contributes to anther development by providing enzymes and materials for pollen coat biosynthesis and nutrients for pollen development. At the end of anther development, the tapetum is degenerated, and the anther is dehisced, releasing mature pollen grains. In Arabidopsis, several genes are known to regulate tapetum formation and pollen development. However, little is known about how tapetum degeneration and anther dehiscence are regulated. Here, we show that an activation-tagged mutant of the S HI-R ELATED S EQUENCE 7 (SRS7) gene exhibits disrupted anther dehiscence and abnormal floral organ development in addition to its dwarfed growth with small, curled leaves. In the mutant hypocotyls, cell elongation was reduced, and gibberellic acid sensitivity was diminished. Whereas anther development was normal, its dehiscence was suppressed in the dominant srs7-1D mutant. In wild-type anthers, the tapetum disappeared at anther development stages 11 and 12. In contrast, tapetum degeneration was not completed at these stages, and anther dehiscence was inhibited, causing male sterility in the mutant. The SRS7 gene was expressed mainly in the filaments of flowers, where the DEFECTIVE-IN-ANTHER-DEHISCENCE 1 (DAD1) enzyme catalyzing jasmonic acid (JA) biosynthesis is accumulated immediately before flower opening. The DAD1 gene was induced in the srs7-1D floral buds. In fully open flowers, the SRS7 gene was also expressed in pollen grains. It is therefore possible that the abnormal anther dehiscence and floral development of the srs7-1D mutant would be related with JA.
Sang-Gyu Kim; Sangmin Lee; Youn-Sung Kim; Dae-Jin Yun; Je-Chang Woo; Chung-Mo Park. Activation tagging of an Arabidopsis SHI-RELATED SEQUENCE gene produces abnormal anther dehiscence and floral development. Plant Molecular Biology 2010, 74, 337 -351.
AMA StyleSang-Gyu Kim, Sangmin Lee, Youn-Sung Kim, Dae-Jin Yun, Je-Chang Woo, Chung-Mo Park. Activation tagging of an Arabidopsis SHI-RELATED SEQUENCE gene produces abnormal anther dehiscence and floral development. Plant Molecular Biology. 2010; 74 (4-5):337-351.
Chicago/Turabian StyleSang-Gyu Kim; Sangmin Lee; Youn-Sung Kim; Dae-Jin Yun; Je-Chang Woo; Chung-Mo Park. 2010. "Activation tagging of an Arabidopsis SHI-RELATED SEQUENCE gene produces abnormal anther dehiscence and floral development." Plant Molecular Biology 74, no. 4-5: 337-351.
• Findings regarding the role of salicylic acid (SA) in seed germination are somewhat variable, depending on the plant genotypes and experimental conditions used, and thus the molecular mechanisms underlying SA regulation of germination are still unclear. Here, we report that physiological concentrations of SA promote germination under high salinity by modulating antioxidant activity in Arabidopsis. • Germination of SA induction deficient 2 (sid2) seeds was hypersensitive to high salinity. While the inhibitory effect of high salinity was exaggerated in the presence of higher concentrations of SA (> 100 μM), it was significantly reduced in the presence of lower concentrations of SA (< 50 μM). Under high salinity, the endogenous contents of H(2) O(2) were elevated in wild-type and sid2 seeds but reduced to original concentrations after treatment with 1 μM SA. • Germination of NahG transgenic plants was influenced to a lesser degree by high salinity (NahG is a bacterial gene encoding salicylate hydroxylase that converts salicylic acid to catechol). We found that catechol, an SA degradation product accumulated in the transgenic plants, acts as an antioxidant that compromises the inhibitory effects of high salinity. • Our observations indicate that, although SA is not essential for germination under normal growth conditions, it plays a promotive role in seed germination under high salinity by reducing oxidative damage.
Sangmin Lee; Sang‐Gyu Kim; Chung‐Mo Park. Salicylic acid promotes seed germination under high salinity by modulating antioxidant activity in Arabidopsis. New Phytologist 2010, 188, 626 -637.
AMA StyleSangmin Lee, Sang‐Gyu Kim, Chung‐Mo Park. Salicylic acid promotes seed germination under high salinity by modulating antioxidant activity in Arabidopsis. New Phytologist. 2010; 188 (2):626-637.
Chicago/Turabian StyleSangmin Lee; Sang‐Gyu Kim; Chung‐Mo Park. 2010. "Salicylic acid promotes seed germination under high salinity by modulating antioxidant activity in Arabidopsis." New Phytologist 188, no. 2: 626-637.
Many transcription factors are stored in a dormant state through association with the cellular membranes in plants. Upon stimulation by internal and environmental signals, they are activated through proteolytic cleavage events either by membrane-associated proteases or by ubiquitination-dependent proteasome activities. Controlled proteolytic activation of the dormant, membrane-bound transcription factors (MTFs) is an intriguing way of ensuring rapid transcriptional responses to abrupt environmental changes. However, the underlying activation mechanisms and protein structural requirements are largely unknown in most cases. Here, we analyzed the primary and secondary structures of the NAC MTFs, particularly of the amino acid sequences surrounding the putative cleavage sites. Interestingly, the putative biologically active forms have strong hydrophilic motifs at their C-termini. Accordingly, transgenic Arabidopsis plants overexpressing the truncated forms having the C-terminal hydrophilic motifs exhibited distinct phenotypes. The finding was also applicable to rice NAC MTFs. Among the full-size OsNTL2 protein and a series of truncated OsNTL2 forms lacking the C-terminal transmembrane motif, only the OsNTL2 form (Os2ΔC4) having a strong hydrophilic peak at the C-terminus exhibited a high transcriptional activation activity when assayed in yeast cells. Our findings will provide insights into how plant MTFs are activated to release the biologically active forms.
Sang-Gyu Kim; Sangmin Lee; Jaeyong Ryu; Chung-Mo Park. Probing protein structural requirements for activation of membrane-bound NAC transcription factors in Arabidopsis and rice. Plant Science 2010, 178, 239 -244.
AMA StyleSang-Gyu Kim, Sangmin Lee, Jaeyong Ryu, Chung-Mo Park. Probing protein structural requirements for activation of membrane-bound NAC transcription factors in Arabidopsis and rice. Plant Science. 2010; 178 (3):239-244.
Chicago/Turabian StyleSang-Gyu Kim; Sangmin Lee; Jaeyong Ryu; Chung-Mo Park. 2010. "Probing protein structural requirements for activation of membrane-bound NAC transcription factors in Arabidopsis and rice." Plant Science 178, no. 3: 239-244.
Controlled proteolytic activation of membrane-bound transcription factors (MTFs) is recently emerging as a versatile way of rapid transcriptional responses to environmental changes in plants. Here, we report genome-scale identification of putative MTFs in the Arabidopsis and rice genomes. The Arabidopsis and rice genomes have at least 85 and 45 MTFs, respectively, in virtually all major transcription factor families. Of particular interest is the NAC MTFs (designated NTLs): there are at least 18 NTLs in Arabidopsis and 5 NTL members (OsNTLs) in rice. While the full-size OsNTL forms are associated with the membranes, truncated forms lacking the transmembrane domains are detected exclusively in the nucleus. Furthermore, transcript levels of the OsNTL genes were elevated after treatments with abiotic stresses, supporting their roles in plant stress responses. We propose that membrane-mediated transcriptional control is a critical component of gene regulatory network that serves as an adaptive strategy under unfavorable growth conditions.
Sang-Gyu Kim; Sangmin Lee; Pil Joon Seo; Soon-Kap Kim; Jeong-Kook Kim; Chung-Mo Park. Genome-scale screening and molecular characterization of membrane-bound transcription factors in Arabidopsis and rice. Genomics 2010, 95, 56 -65.
AMA StyleSang-Gyu Kim, Sangmin Lee, Pil Joon Seo, Soon-Kap Kim, Jeong-Kook Kim, Chung-Mo Park. Genome-scale screening and molecular characterization of membrane-bound transcription factors in Arabidopsis and rice. Genomics. 2010; 95 (1):56-65.
Chicago/Turabian StyleSang-Gyu Kim; Sangmin Lee; Pil Joon Seo; Soon-Kap Kim; Jeong-Kook Kim; Chung-Mo Park. 2010. "Genome-scale screening and molecular characterization of membrane-bound transcription factors in Arabidopsis and rice." Genomics 95, no. 1: 56-65.