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RISS 인기검색어
- 검색키워드
- 저자 : Laila Khaleda (검색결과 9 건)
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Khaleda, Laila,Park, Hee Jin,Yun, Dae-Jin,Jeon, Jong-Rok,Kim, Min Gab,Cha, Joon-Yung,Kim, Woe-Yeon Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.12
Excessive salt disrupts intracellular ion homeostasis and inhibits plant growth, which poses a serious threat to global food security. Plants have adapted various strategies to survive in unfavorable saline soil conditions. Here, we show that humic acid (HA) is a good soil amendment that can be used to help overcome salinity stress because it markedly reduces the adverse effects of salinity on Arabidopsis thaliana seedlings. To identify the molecular mechanisms of HA-induced salt stress tolerance in Arabidopsis, we examined possible roles of a sodium influx transporter HIGH-AFFINITY $K^+$ TRANSPORTER 1 (HKT1). Salt-induced root growth inhibition in HKT1 overexpressor transgenic plants (HKT1-OX) was rescued by application of HA, but not in wild-type and other plants. Moreover, salt-induced degradation of HKT1 protein was blocked by HA treatment. In addition, the application of HA to HKT1-OX seedlings led to increased distribution of $Na^+$ in roots up to the elongation zone and caused the reabsorption of $Na^+$ by xylem and parenchyma cells. Both the influx of the secondary messenger calcium and its cytosolic release appear to function in the destabilization of HKT1 protein under salt stress. Taken together, these results suggest that HA could be applied to the field to enhance plant growth and salt stress tolerance via post-transcriptional control of the HKT1 transporter gene under saline conditions.
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Laila Khaleda,차준영,김민갑,김외연 한국식물학회 2017 Journal of Plant Biology Vol.60 No.6
Arabidopsis GIGANTEA (GI) is encoded by asingle gene and highly conserved among vascular plants andits mutants display pleiotropic phenotypes involved indiverse biological processes such as light signaling, circadianclock, and sucrose metabolism as well as abiotic stressresponses. However, molecular mechanisms of GI arelargely unknown due to the lack of useful antibody. To date,the epitope tags have been widely used to detect GI in plants,but it needs to generate the transgenic plants which take afew months. Here, we produced polyclonal α-GI antibodyusing truncated variants of GI having amino-terminal (1-858aa) and carboxyl-terminal (920-1173) regions as antigens. Both recombinant His-GI1-858 and His-GI920-1173 proteins wereindividually and successfully expressed in E. coli andimmunized into rabbit. Anti-serum was purified by antigenspecificaffinity purification method using both recombinantHis-GI1-858 and His-GI920-1173 proteins. Purified polyclonal α-GI antibody not only detected endogenous GI proteins inwild-type Arabidopsis plants, but also reenacted its dieloscillations. Furthermore, the antibody showed cross-reactivitywith the GI orthologs in other plants such as Chinesecabbage, rape and tomato. Our polyclonal GI antibody couldhelp to determine the molecular mechanisms of GI involvedin largely unknown pleiotropic responses in plants.
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Humic Acid and Synthesized Humic Mimic Promote the Growth of Italian Ryegrass
Khaleda, Laila,Kim, Min Gab,Kim, Woe-Yeon,Jeon, Jong-Rok,Cha, Joon-Yung The Korean Society of Grassland and Forage Science 2017 한국초지조사료학회지 Vol.37 No.3
Humic acid (HA) is a complex organic matter found in the environments, especially in grassland soils with a high density. The bioactivity of HA to promote plant growth depends largely on its extraction sources. The quality-control of HA and the quality improvements via an artificial synthesis are thus challenging. We recently reported that a polymeric product from fungal laccase-mediated oxidation of catechol and vanillic acid (CAVA) displays a HA-like activity to enhance seed germination and salt stress tolerance in a model plant, Arabidopsis. Here, we examined whether HA or CAVA enhances the growth of Italian ryegrass seedling. Height and fresh weight of the plant with foliar application of HA or CAVA were bigger than those with only water. Interestingly, enhanced root developments were also observed in spite of the foliar treatments of HA or CAVA. Finally, we proved that HA or CAVA promotes the regrowth of Italian ryegrass after cutting. Collectively, CAVA acts as a HA mimic in Italian ryegrass cultivation, and both as a biostimulant enhanced the early growth and regrowth after cutting of Italian ryegrass, which could improve the productivity of forage crops.
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Humic Acid Confers HIGH-AFFINITY K+ TRANSPORTER 1-Mediated Salinity Stress Tolerance in Arabidopsis
Laila Khaleda,박희진,윤대진,전종록,김민갑,차준영,김외연 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.12
Excessive salt disrupts intracellular ion homeostasis and inhibits plant growth, which poses a serious threat to global food security. Plants have adapted various strategies to survive in unfavorable saline soil conditions. Here, we show that humic acid (HA) is a good soil amendment that can be used to help overcome salinity stress because it markedly reduces the adverse effects of salinity on Arabidopsis thaliana seedlings. To identify the molecular mechanisms of HA-induced salt stress tolerance in Arabidopsis, we examined possible roles of a sodium influx transporter HIGH-AFFINITY K+ TRANSPORTER 1 (HKT1). Salt-induced root growth inhibition in HKT1 overexpressor transgenic plants (HKT1-OX) was rescued by application of HA, but not in wild-type and other plants. Moreover, salt-induced degradation of HKT1 protein was blocked by HA treatment. In addition, the application of HA to HKT1-OX seedlings led to increased distribution of Na+ in roots up to the elongation zone and caused the reabsorption of Na+ by xylem and parenchyma cells. Both the influx of the secondary messenger calcium and its cytosolic release appear to func-tion in the destabilization of HKT1 protein under salt stress. Taken together, these results suggest that HA could be applied to the field to enhance plant growth and salt stress tolerance via post-transcriptional control of the HKT1 transporter gene under saline conditions.
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Khaleda, Laila,Cha, Joon-Yung,Kim, Min Gab,Kim, Woe-Yeon Botanical Society of Korea 2017 Journal of plant biology Vol.60 No.6
<P>Arabidopsis GIGANTEA (GI) is encoded by a single gene and highly conserved among vascular plants and its mutants display pleiotropic phenotypes involved in diverse biological processes such as light signaling, circadian clock, and sucrose metabolism as well as abiotic stress responses. However, molecular mechanisms of GI are largely unknown due to the lack of useful antibody. To date, the epitope tags have been widely used to detect GI in plants, but it needs to generate the transgenic plants which take a few months. Here, we produced polyclonal alpha-GI antibody using truncated variants of GI having amino-terminal (1-858 aa) and carboxyl-terminal (920-1173) regions as antigens. Both recombinant His-GI(1-858) and His-GI(920-1173) proteins were individually and successfully expressed in E. coli and immunized into rabbit. Anti-serum was purified by antigenspecific affinity purification method using both recombinant His-GI(1-858) and His-GI(920-1173) proteins. Purified polyclonal alpha-GI antibody not only detected endogenous GI proteins in wild-type Arabidopsis plants, but also reenacted its diel oscillations. Furthermore, the antibody showed cross-reactivity with the GI orthologs in other plants such as Chinese cabbage, rape and tomato. Our polyclonal GI antibody could help to determine the molecular mechanisms of GI involved in largely unknown pleiotropic responses in plants.</P>
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Khaleda, Laila,Kim, Min Gab,Jeon, Jong-Rok,Cha, Joon-Yung,Kim, Woe-Yeon The Korean Society of Grassland and Forage Science 2017 한국초지조사료학회지 Vol.37 No.3
Humic acid (HA) is known to consist of various kinds of polymeric organics, their detailed structures can vary depend on sample sources such as organic manure, composts, peat, and lignite brown coal, and largely exists in grassland soils. HA possesses diverse positive effects that not only increase plant growth but also improve soil fertility. Recently, we have manufactured a co-polymeric product of catechol and vanillic acid (CAVA) synthesized artificially, and found that CAVA as a HA mimic increases seed germination and salt tolerance in Arabidopsis. In this study, we examined whether HA or CAVA affects to seedling growth in alfalfa. Foliar application of HA or CAVA increased alfalfa seedling growth including aerial and in root parts. HA or CAVA dramatically enhanced size of leaf and root, whereas HA significantly displayed higher bioactivity than CAVA. Taken together, CAVA acts like as a HA mimic in alfalfa that could apply as an alternation supplement to enhance plant growth and productivity.
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김미리,Laila Khaleda,정인정,김주연,이상열,차준영,김외연 한국식물학회 2017 Journal of Plant Biology Vol.60 No.2
Chloroplast is a major organelle that conducts photosynthesis to produce ATP and NADPH via conversion of water to oxygen in plant. While the photosynthesis occurs, molecular oxygen easily changes to reactive oxygen species (ROS) consisting of toxic oxygen radicals resulting in oxidative stress. NADPH-dependent thioredoxin reductases (NTRs) play a pivotal role to regulate the redox state of the thioredoxin system providing reducing power to peroxidase. Here, we identify whether chloroplast NTRC confers stress tolerance through maintenance of ROS in Arabidopsis. NTRC transcripts were two-fold induced at 1 h treatment exposed to a photooxidative agent, methyl viologen (MV). The enhanced NTRC transcripts conferred oxidative stress tolerance displaying that NTRC overexpressing plants (NTRCOX) were tolerant compared to Col-0 and knock-out (ntrc-ko) plants on MVcontaining media. MV-mediated ROS induction was not detected in NTRCOX whereas that was highly accumulated in Col-0 and ntrc-ko. We further examined that NTRCOX showed extreme drought tolerance with lower water loss compared to Col-0 and ntrc-ko. Drought-responsive genes such as RD29A and DREB2A were enhanced in NTRCOX by drought compared to Col-0 and ntrc-ko. The results suggest that NTRC overexpression contributes to maintaining ROS homeostasis under stress conditions and confers the tolerance to photo-oxidative and drought stresses.
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A chaperone surveillance system in plant circadian rhythms
( Joon-yung Cha ),( Laila Khaleda ),( Hee Jin Park ),( Woe-yeon Kim ) 생화학분자생물학회(구 한국생화학분자생물학회) 2017 BMB Reports Vol.50 No.5
The circadian clock is an internal system that is synchronized by external stimuli, such as light and temperature, and influences various physiological and developmental processes in living organisms. In the model plant Arabidopsis, trans-criptional, translational and post-translational processes are interlocked by feedback loops among morning- and evening-phased genes. In a post-translational loop, plant-specific singlegene encoded GIGANTEA (GI) stabilize the F-box protein ZEITLUPE (ZTL), driving the targeted-proteasomal degradation of TIMING OF CAB EXPRESSION 1 (TOC1) and PSEUDO-RESPONSE REGULATOR 5 (PRR5). Inherent to this, we demonstrate the novel biochemical function of GI as a chaperone and/or co-chaperone of Heat-Shock Protein 90 (HSP90). GI prevents ZTL degradation as a chaperone and facilitates ZTL maturation together with HSP90/HSP70, enhancing ZTL activity in vitro and in planta. GI is known to be involved in a wide range of physiology and development as well as abiotic stress responses in plants, but it could also interact with diverse client proteins to increase protein maturation. Our results provide evidence that GI helps pro-teostasis of ZTL by acting as a chaperone and a co-chaperone of HSP90 for proper functioning of the Arabidopsis circadian clock. [BMB Reports 2017; 50(5): 235-236]
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Cha, Joon-Yung,Kim, Tae-Wan,Choi, Jung Hoon,Jang, Kyoung-Soon,Khaleda, Laila,Kim, Woe-Yeon,Jeon, Jong-Rok American Chemical Society 2017 Journal of agricultural and food chemistry Vol.65 No.6
<P>Fungal laccases have been highlighted as a catalytic tool for transforming phenols. Here we demonstrate that fungal laccase-catalyzed oxidations can transform naturally occurring phenols into plant fertilizers with properties very similar to those of commercial humic acids. Treatments of Arabidopsis thaliana with highly cross-linked polyphenolic products obtained from a mixture of catechol and vanillic acid were able to enhance the germination and salt tolerance of this plant. These results revealed that humic-like organic fertilizers can be produced via in vitro enzymatic oxidation reactions. In particular, the root elongation pattern resulting from the laccase products was comparable to that resulting from an auxin-like compound. A detailed structural comparison of the phenol variants and commercial humic acids revealed their similarities and differences. Analyses based on SEM, EFM, ERP, and zeta-potential measurement showed that they both formed globular granules bearing various hydrophilic/polar groups in aqueous and solid conditions. Solid-phase C-13 NMR, FT-IR-ATR, and elemental analyses showed that more nitrogen-based functional and aliphatic groups were present in the commercial humic acids. Significant differences were also identifiable with respect to particle size and specific surface area. High-resolution (15 T) FT-ICR mass spectrometry based van Krevelen diagrams showed the compositional features of the variants to be a subset of those of the humic acids. Overall, our study unraveled essential structural features of polyaromatics that affect the growth of plants, and also provided novel bottom-up ecofriendly and finely tunable pathways for synthesizing humic-like fertilizers.</P>
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