• The Plant Pathology Journal
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• 제29권4호
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• pp.427-434
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• 2013

2R,3R-Butanediol, a volatile compound produced by certain rhizobacteria, is involved in induced drought tolerance in Arabidopsis thaliana through mechanisms involving stomatal closure. In this study, we examined the involvement of nitric oxide and hydrogen peroxide in induced drought tolerance, because these are signaling agents in drought stress responses mediated by abscisic acid (ABA). Fluorescence-based assays showed that systemic nitric oxide and hydrogen peroxide production was induced by 2R,3R-butanediol and correlated with expression of genes encoding nitrate reductase and nitric oxide synthase. Co-treatment of 2R,3R-butanediol with an inhibitor of nitrate reductase or an inhibitor of nitric oxide synthase lowered nitric oxide production and lessened induced drought tolerance. Increases in hydrogen peroxide were negated by co-treatment of 2R,3R-butanediol with inhibitors of NADPH oxidase, or peroxidase. These findings support the volatile 2R,3R-butanediol synthesized by certain rhizobacteria is an active player in induction of drought tolerance through mechanisms involving nitric oxide and hydrogen peroxide production.

• The Plant Pathology Journal
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• 제29권4호
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• pp.471-476
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• 2013

Plants are frequently exposed to numerous environmental stresses such as dehydration and high salinity, and have developed elaborate mechanisms to counteract the deleterious effects of stress. The phytohormone abscisic acid (ABA) plays a critical role as an integrator of plant responses to water-limited condition to activate ABA signal transduction pathway. Although perception of ABA has been suggested to be important, the function of each ABA receptor remains elusive in dehydration condition. Here, we show that ABA receptor, pyrabactin resistance-like protein 8 (PYL8), functions in dehydration conditions. Transgenic plants overexpressing PYL8 exhibited hypersensitive phenotype to ABA in seed germination, seedling growth and establishment. We found that hypersensitivity to ABA of transgenic plants results in high degrees of stomatal closure in response to ABA leading to low transpiration rates and ultimately more vulnerable to drought than the wild-type plants. In addition, high expression of ABA maker genes also contributes to altered drought tolerance phenotype. Overall, this work emphasizes the importance of ABA signaling by ABA receptor in stomata during defense response to drought stress.

• Molecules and Cells
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• 제41권5호
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• pp.413-422
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• 2018

Soybean transgenic plants with ectopically expressed AtABF3 were produced by Agrobacterium-mediated transformation and investigated the effects of AtABF3 expression on drought and salt tolerance. Stable Agrobacterium-mediated soybean transformation was carried based on the half-seed method (Paz et al. 2006). The integration of the transgene was confirmed from the genomic DNA of transformed soybean plants using PCR and the copy number of transgene was determined by Southern blotting using leaf samples from $T_2$ seedlings. In addition to genomic integration, the expression of the transgenes was analyzed by RT-PCR and most of the transgenic lines expressed the transgenes introduced. The chosen two transgenic lines (line #2 and #9) for further experiment showed the substantial drought stress tolerance by surviving even at the end of the 20-day of drought treatment. And the positive relationship between the levels of AtABF3 gene expression and drought-tolerance was confirmed by qRT-PCR and drought tolerance test. The stronger drought tolerance of transgenic lines seemed to be resulted from physiological changes. Transgenic lines #2 and #9 showed ion leakage at a significantly lower level (P < 0.01) than ${\underline{n}}on-{\underline{t}}ransgenic$ (NT) control. In addition, the chlorophyll contents of the leaves of transgenic lines were significantly higher (P < 0.01). The results indicated that their enhanced drought tolerance was due to the prevention of cell membrane damage and maintenance of chlorophyll content. Water loss by transpiration also slowly proceeded in transgenic plants. In microscopic observation, higher stomata closure was confirmed in transgenic lines. Especially, line #9 had 56% of completely closed stomata whereas only 16% were completely open. In subsequent salt tolerance test, the apparently enhanced salt tolerance of transgenic lines was measured in ion leakage rate and chlorophyll contents. Finally, the agronomic characteristics of ectopically expressed AtABF3 transgenic plants ($T_2$) compared to NT plants under regular watering (every 4 days) or low rate of watering condition (every 10 days) was investigated. When watered regularly, the plant height of drought-tolerant line (#9) was shorter than NT plants. However, under the drought condition, total seed weight of line #9 was significantly higher than in NT plants (P < 0.01). Moreover, the pods of NT plants showed severe withering, and most of the pods failed to set normal seeds. All the evidences in the study clearly suggested that overexpression of the AtABF3 gene conferred drought and salt tolerance in major crop soybean, especially under the growth condition of low watering.

• 한국작물학회지
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• 제44권3호
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• pp.282-287
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• 1999

The object of this study was to determine the difference of the time course changes of transpiration, diffusion resistance and photosynthetic rate of rice at several different growth stages subjected to soil moisture stress (SMS) and recovery by irrigation. A japonica rice cultivar 'Dongjinbyeo', was grown under flooded condition in a plastic container filled with silty loam soil. At 5 main growth stages, the container was treated by SMS until initial wilting point (IWP) and then reirrigated. The duration of SMS until IWP were the longest, 13 days for tillering stage, and the shortest, 7 days for panicle initiation and meiosis stage. The transpiration rate rapidly decreased during SMS and the transpiration rate at IWP of the stressed plant showed 10∼20% compared with control, and the transpiration rate of stressed plant at most growth stages also recovered rapidly after irrigation and then reached 100% of control within a week. The shoot photosynthetic rate in all growth stages rapidly decreased by SMS, and the rates at IWP of stressed plants were de-creased nearly to 0%, beside the treatment at tillering stage. The recovery degree of photosynthetic rate by irrigation ranged from 20 to 90%, showed higher at early growth stages of SMS treatment than that of later stages. At all growth stages the leaf diffusion resistance of stressed plants was over 3 times that of the control resulting from a rapid increase at 3 to 5 days after draining for SMS, and showed quick recovery by irrigation within 3 days after drainage. The above physiological parameters changed in close relation with the decrease of the soil matric potential after SMS. These results indicate that at all main growth stages of rice plants the transpiration and photosynthesis reduction by stomatal closure reponded sensitively to the first stage of SMS closely related with decrease of soil water potential, while those recovery pattern and recovered degree by irrigation are little different by growth stage of rice.

• The Plant Pathology Journal
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• 제34권3호
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• pp.236-240
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• 2018

Crop yield is critically related to the physiological responses and disease resistance of the crop, which could be strongly affected by high temperature conditions. We observed the changes in the growth of barley under higher than ambient air-temperature conditions using a temperature gradient field chamber (TGFC) during winter and spring. Before the stem extension stage of barley growth, Cladosporium sp. spontaneously appeared in the TGFC. The severity of disease became serious under warmer temperature conditions. Further, the stomata closed as the severity of the disease increased; however, stomatal conductance at the initial stage of disease was higher than that of the normal leaves. This was likely due to the Iwanov effect, which explains that stressed plants rapidly and transiently open their stomata before longer-term closure. In this study, we tested three optical methods: soil-plant analysis development (SPAD) chlorophyll index, photochemical reflectance index (PRI), and maximum quantum yield (Fv/Fm). These rapid evaluation methods have not been used in studies focusing on disease stress, although some studies have used these methods to monitor other stresses. These three indicative parameters revealed that diseased barley exhibited lower values of these parameters than normal, and with the increase in disease severity, these values declined further. Our results will be useful in efficient monitoring and evaluation of crop diseases under future warming conditions.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.149-149
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• 2017

The RING (Really Interesting New Gene) finger proteins are known to play crucial roles in various abiotic stresses in plants. In this study, we report on RING finger E3 ligase, ${\underline{O}ryza}$ ${\underline{s}ativa}$ ${\underline{s}alt$-, ${\underline{A}BA}$- and ${\underline{d}rounght}$ stress-${\underline{i}nduced}$ RING finger ${\underline{p}}rotein{\underline{1}}$ gene (OsSAD1). In vitro ubiquitination assay demonstrated that unlike OsSAD1, a single amino acid substitution ($OsSAD1^{C168A}$) of the RING domain showed no E3 ligase activity, supporting the notion that the activity of most E3s is specified by a RING domain. Result of Yeast-Two hybridization, In vivo protein degradation assay supports that OsSAD1 interacting with 3 substrate, OsSNAC2, OsGRAS44 and OsPIRIN1, and mediates proteolysis of 3 substrates via the 26S proteasome pathway. Subcellular localizations of OsSAD1 while approximately 62% of transient signals were detected in cytosol, 38% of signals were showed nucleus. However, transiently expression of OsSAD1 was detected in cytosol 30% while as 70% of nucleus under 200 mM salt treated rice protoplasts. Results of bimolecular fluorescence complementation (BiFC) showed that two nucleus-localized proteins (OsSNAC2 and OsGRAS44) interacted with OsSAD1 in the both cytosol and nucleus. Heterogeneous overexpression of OsSAD1 Heterogeneous overexpresssion of OsSAD1 in Arabidopsis exhibited sensitive phenotypes with respect to Salt-, mannitol-responsive seed germination, seedling growth. In ABA conditions, OsSAD1 overexpression plants showed highly tolerance phenotypes, such as root length and stomatal closure. Our findings suggest that the OsSAD1 may play a negative regulator in salt stress response by modulating levels of its target proteins.

• 생명과학회지
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• 제22권11호
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• pp.1515-1522
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• 2012

식물호르몬인 abscisic acid (ABA)는 식물의 비생물학적 스트레스의 적응과정에서 중요한 역할을 수행하고 있다. 또한 ABA는 종자휴면, 발아, 세포분열의 저해, 기공개폐와 같은 중요한 과정에 관여하고 있다. OsABF2(Oryza sativa ABRE Binding Factor2)는 벼에서 비생물학적 스트레스와 ABA 신호전달 과정에 양성적으로 관여하는 bZIP 형태의 전사인자이다. OsABF2 유전자의 발현은 ABA와 다양한 스트레스 처리에 의해 유도된다. 본 논문에서는 OsABF2 유전자를 과발현한 애기장대가 가뭄, 고염, 고온 상태에서의 생존율이 야생형보다 증가하는 것을 확인하였다. 또한 ABA가 존재하는 상황에서 OsABF2 유전자를 과발현한 애기장대의 발아율이 감소하는 것을 확인하였다. 이러한 결과로 미루어 OsABF2 유전자를 과발현한 애기장대는 비생물학적 스트레스에 대한 내성이 증가하고 ABA 감수성은 증가하는 것으로 확인되었다.

• Genes and Genomics
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• 제40권12호
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• pp.1287-1300
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• 2018

Hydrogen sulfide ($H_2S$), a small bioactive gas, has been proved functioning in plant growth and development as well as alleviation of abiotic stresses, which including promoting seed germination, accelerating embryonic root growth, regulating flower senescence, inducing stomatal closure, and defending drought, heat, heavy metals and osmotic stresses etc. However, the molecular functioning mechanism of $H_2S$ was still unclear. The primary objective of this research was to analyze the transcriptional differences and functional genes involved in the $H_2S$ responses. In details, 4-week-old plantlets in tissue culture of grapevine (Vitis vinifera L.) cultivar 'Zuoyouhong' were sprayed with 0.1 mM NaHS for 12 h, and then transcriptome sequencing and qRT-PCR analysis were used to study the transcriptional differences and functional genes involved in the $H_2S$ responses. Our results indicated that 650 genes were differentially expressed after $H_2S$ treatment, in which 224 genes were up-regulated and 426 genes were down-regulated. The GO enrichment analysis and KEGG enrichment analysis results indicated that the up-regulated genes after $H_2S$ treatment focused on carbon metabolism, biosynthesis of amino acids, and glycolysis/gluconeogenesis, and the down-regulated genes were mainly in metabolic pathways, biosynthesis of secondary metabolites, and plant hormone signal transduction. Analyzing the transcription factor coding genes in details, it was indicated that 10 AP2/EREBPs, 5 NACs, 3 WRKYs, 3 MYBs, and 2 bHLHs etc. transcription factor coding genes were up-regulated, while 4 MYBs, 3 OFPs, 3 bHLHs, 2 AP2/EREBPs, 2 HBs etc. transcription factor coding genes were down-regulated. Taken together, $H_2S$ increased the productions in secondary metabolites and a variety of defensive compounds to improve plant development and abiotic resistance, and extend fruits postharvest shelf life by regulating the expression of AP2/EREBPs, WRKYs, MYBs, CABs, GRIP22, FERRITINs, TPSs, UGTs, and GHs etc.

• 한국잡초학회지
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• 제1권1호
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• pp.57-68
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• 1981

수도묘(水稻苗)의 Butachlor(2-chloro-2',6'-diethyl-N-(carboxymethyl) acetanilide) 흡수특성(吸收特性)과 약해발생가구(藥害發生機構)를 밝히어 Butachlor의 안전사용(安全使用)에 도움을 주고자 시도(試圖)되었다. 수도품종(水稻品種) '만석(萬石)'(수원(水原)264호(號))을 사용(使用)하여 제(第)6, 7여기(葉期)까지 수경재배(水耕栽培)한 후 Butachlor를 0, 1.8, 3.6, 7.2, 10.8 또는 14.4ppm 되도록 처리(處理한) 수경액(水耕液)으로 1, 2, 4일간(日間) 생육(生育)시킨 경우와 Butachlor 처리(處理) 후(後) 정상수경액(正常水耕液)으로 교체(交替)하고 6일간(間生) 생장(生長)시킬 경우 약해(藥害)의 진전(進展) 또는 회복과정중(恢復過程中)에 일어나는 수도(水稻)의 Butachlor 흡수(吸收)에 따른 생장반응(生長反應), 수분흡수(水分吸收), 양분흡수(養分吸收), 기공(氣孔) 개폐(開閉), 질산환원효소(窒酸還元酵素)(Nitrate reductase)의 생합성(生合成) 및 분해작용(分解作用)의 변화(變化)를 검정(檢定)했고 Butachlor의 세포구성물질(細胞構成物質)들에 대한 흡착특성(吸着特性)을 비교(比較)하였으며 그 결과(結結)는 다음과 같이 요약(要約)된다. 1. 수도묘(水稻苗)의 Butachlor의 흡수(吸收)는 처리농도(處理濃度) 및 기간(期間)에 비례(比例)하여 거의 직선적(直線的)으로 증가(增加)하였다. 2. Butachlor는 지상부(地上部) 생육(生育)보다는 뿌리생육(生育)을, 지상부(地上部) 생체중(生體重) 및 출엽(出葉)보다는 초장(草長)의 생육(生育)을 더욱 저해(沮害)하였으며, 처리종료(處理終了) 후(後) 지상부(地上部) 생체중(生體重)과 출엽(出葉)은 조속(早速)히 회복(恢復)되었으나 초장(草長) 및 뿌리생체중(生體重) 생장(生長)은 4일(日) 이후(以後) 회복세(恢復勢)를 보였다. 3. Butachlor는 뿌리의 수분흡수(水分吸收)를 처리농도(處理濃度) 비례(比例)하여 곧 저해(沮害)하였고, 그 결과(結果) 엽면(葉面) 기공(氣孔)의 저항(低抗)을 증가(增加)시켰으며, 처리종료(處理終了) 후(後)에는 수분흡수력(水分吸收力)은 곧 회복(恢復)되었으나 기공(氣孔)의 개도(開度)는 서서히 회복(恢復)되었다. 4. Butachlor는 처리(處理) 전(前) 후(後) 수도묘(水稻苗)의 $NH_4^+$, $K^+$ 및 $Ca^{++}$ 같은 양(陽)이온의 흡수(吸收)에는 영향(影響)하지 않았으나 $NO_3^-$의 흡수(吸收)를 뚜렷이 저해(沮害)했고, 7.2 ppm의 고종도(高濃度)에서는 인산(燐酸)의 흡수(吸收)도 저해(沮害)했다.

• 한국산림과학회지
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• 제111권3호
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• pp.405-417
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• 2022

본 연구는 건조 스트레스에 따른 Prunus maximowiczii(산개벚나무) 및 Prunus serrulate Lindl. var. pubescens(Makino)Nakai(잔털벚나무)의 광합성 특성 및 광계II 활성에 미치는 영향을 알아보고자 수행하였으며, 건조 스트레스(drought stress, DS)는 30일간의 단수처리를 통해 유도하였다. 건조 스트레스가 진행됨에 따라 토양 수분함량은 감소하였으며, DS 10~12일 사이에 두 수종모두 10% 이하로 건조한 상태가 되고, DS 15일 이후부터는 5% 이하로 나타나 위조가 시작되는 조건에 해당되었다. DS 10일부터 최대광합성 속도, 광보상점의 감소가 두드러졌고, 암호흡 및 순양자수율은 DS 15일에 크게 감소하다가 DS 20일 이후부터 증가하는 경향을 보였다. 또한 산개벚나무의 기공증산속도는 DS 15일에 크게 감소한 뒤 DS 20일 이후부터 증가하였으며, 수분이용효율은 DS 15일에 증가한 뒤 DS 20일 이후부터 감소하였다. 잔털벚나무의 경우 기공증산속도는 DS 20일에 크게 감소한 뒤 이후부터 증가하였으며, 수분이용효율은 DS 20일에 증가한 뒤 이후부터 감소하는 경향을 보였다. 이는 수분 손실을 막기 위해 기공을 닫게 되어 수분이용효율이 일시적으로 증가한 것을 의미한다. 엽록소 형광분석을 통해 산개벚나무는 DS 15일, 잔털벚나무는 DS 20일 이후에 기능지수(PI_ABS) 및 에너지전달 효율의 감소가 두드려졌으며, 광계II의 활성이 감소되었다. 특히, Ts-Ta, PI_ABS, DI_O/RC, ET_O/RC는 토양수분함량의 감소와 광합성 특성과도 유사하게 나타나, 수목의 건조 스트레스를 평가하는데 있어서 유용한 변수로 활용될 수 있을 것으로 보인다.