• Journal of Plant Biotechnology
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• 제49권4호
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• pp.271-291
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• 2022

Pectin methylesterase (PME) plays an important role in vegetative and reproductive development and biotic/abiotic stress responses by regulating the degree of methyl-esterification of pectic polysaccharides in the plant cell wall. PMEs are encoded by a large multigene family in higher land plant genomes. In general, the expression of plant PME genes shows tissue- or cell-specific patterns and is induced by endogenous and exogenous stimuli. In this study, we identified PME multigene family members (CsPMEs) from the sweet orange genome and report detailed molecular characterization and expression profiling in different citrus tissues and two fruit developmental stages. We also discussed the possible functional roles of some CsPME genes by comparing them with the known functions of PMEs from other plant species. We identified 48 CsPME genes from the citrus genome. A phylogenetic tree analysis revealed that the identified CsPMEs were divided into two groups/types. Some CsPMEs showed very close phylogenetic relationships with the PMEs whose functions were formerly addressed in Arabidopsis, tomato, and maize. Expression profiling showed that some CsPME genes are highly or specifically expressed in the leaf, root, flower, or fruit. Based on the phylogenetic relationships and gene expression profiling results, we suggest that some CsPMEs could play functional roles in pollen development, pollen tube growth, cross incompatibility, root development, embryo/seed development, stomata movement, and biotic/abiotic stress responses. Our results shed light on the biological roles of individual CsPME isoforms and contribute to the search for genetic variations in citrus genetic resources.

• 한국조리학회지
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• 제20권2호
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• pp.54-64
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• 2014

레토르트 처리한 양파의 조직감(견고성)을 향상시키기 위하여 칼슘용액에서 장시간 저온(LTLT)블랜칭을 실시하였다. 칼슘용액에서 예비 열처리한 양파는 일반적인 블랜칭과 비교시 고온 멸균한 후 양파의 조직감이 의미있게 향상되었다. LTLT 블랜칭에 의한 견고성의 향상은 양파 조직의 pectin methylesterase(PME) 작용으로 carboxyl 그룹과 2가 양이온($Ca^{2+}$)간의 강한 가교결합과 관련이 있다. 0.5% 칼슘용액에서 $70^{\circ}C$, 120분동안 예비 열처리를 행하였을 때 가장 높은 견고성을 가진 레토르트 처리된 양파를 얻을 수 있었다. 이 같은 결과는 양파에서 PME의 활성도와 결합된 칼슘의 함량이 $70^{\circ}C$에서 가장 높았다는 것을 의미한다. 또한, $Mg^{2+}$와 같은 여러 2가 양이온을 함유하고 있는 알칼리 계통 칼슘이 펙틴 분자를 상온에서 가수분해하는 기작이 효소 작용에 더해져 여러 칼슘용액 중에서 레토르트 처리된 양파의 조직감을 가장 견고하게 하였다. 향후 여러 가지 레토르트 처리된 야채들의 조직 연화 방지를 위한 최적조건 실험이 야채별로 더 많이 수행되어야 할 것이다.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1365-1370
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• 2009

Aspergillus kawachii extracellular pectinases were screened in liquid cultures with different carbon sources. The fungus grown on citrus pectin or lemon pomace produced at least one of these inducible pectinases: acidic polygalacturonase, pectin lyase, pectin methylesterase, $\alpha$-L-arabinofuranosidase, $\alpha$-1,5-endoarabinase, $\beta$-D-galactosidase/exogalactanase, and $\beta$-1,4-endogalactanase. The lemon-pomace filtrates also contained significant $\alpha$-L-rhamnosidase and $\beta$-D-fucosidase activities. Most of the screened pectinases were active at pH 2.0-2.5, indicating that the A. kawachii enzymes were acidophilic. Under the culture conditions employed we could not detect enzymatic degradation of soybean rhamnogalacturonan. The A. kawachii pectinase-production-related regulatory phenomena of induction-repression resemble those described for other Aspergillus sp.

• 한국식품저장유통학회지
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• 제8권2호
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• pp.131-139
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• 2001

Kiyomi tangor(Citus unshiu x sinensis) was stored at 3$\^{C}$ and 85% relative humidity, and the changes in firmness, pectin degrading enzymes activity and other physicochemical properties of citrus fruits during storage were investigated. Decay ratio and weight loss during 180 days’ storage were increased gradually to 13.0% and 12.9%, respectively. Firmness of fruits with 2 mm probe was decreased gradually from 808.7 g-force to 406.4 g-force, and moisture of peel and flesh were decreased from 76.5% to from 89.6% to 87.6% during storage, respectively. Exo-polygalacturonase activity of peel after 150 days’ storage were increased gradually to 558.09 units/100g. Pectin methylesterase activity of peel and flesh were increased from 14.7 units/g to 2.3 units/g, and from 9.4 units/ml to 2.7 units/ml at 150days’ storage, respectively. Endo-polygalacturonase activities were not changed notably during storage. Alcohol-insoluble solid(AIS) of peel was not changed notably. During storage of the fruits water soluble pectin(WSP) of peel and flesh were increased from 474.49 mg/100g to 614.29mg/100g, and from 66.91mg/100g to 92.74mg/100g as wet basis, respectively. Hexameta-phosphate soluble pectin(HMP) of peel were decreased from 405.5mg/100g to 270.43mg/100g, hydochloric acid soluble pectin(HSP) of peel was also decreased from 544.02mg/100g to 412.64mg/100g during storage. Total pectin substance(TPS) of peel and flesh were decreased from 1,424.01mg/100g to 1,297.36mg/100g, and from 165.51mg/100g to 171.54mg/100g, respectively. Composition ratio of pectin was in order of WSP > HSP > HMP.

• 농업과학연구
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• 제37권2호
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• pp.209-216
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• 2010

In order to understand the effects of a single or combined treatments of 1-MCP($1{\mu}L/L$) and $CO_2$(100%) on the firmness of melting type peach fruit(cv. Chunjungdo), fruit were harvested at commercial maturity and examined physiological changes including flesh firmness during 10 days of shelf-life. Firmness loss of fruit was delayed by both single and combined treatments of 1-MCP and $CO_2$. The treatment of 1-MCP was more effective than $CO_2$ treatment but no additive effective on firmness retention was found in the combined treatment. The upsurge of ethylene evolution occurred 5 days of shelf-life in air treated control but ethylene evolution gradually increased in fruit treated by 1-MCP and 1-MCP+$CO_2$. The suppression of ethylene evolution seemed stronger in $CO_2$ treatment. The respiration of fruit significantly inhibited up to 10 days except control where climacteric increase of respiration was found at 10 days of shelf-life. A molecular shift of pectic polymers(an increase of chelator soluble pectins and decrease of water soluble pectins) was induced by both 1-MCP and $CO_2$ treatments. An increase of water soluble pectins was coincident with firmness loss. The delay of firmness loss seemed to be associated with the migration of calcium to wall matrix, especially pectins, resulting in the increase of wall bound calcium. The polygalacturonase activity was significantly reduced by 1-MCP alone 1 day after treatment and increased to similar level of activity 5 days after treatment compared to other treatment except air treated control whereas pectin methylesterase activity seemed not to be affected by both 1-MCP and $CO_2$ treatments. Thus, the molecular shift of pectic polymers appeared not to be related with pectin methylesterase. Further study is required to clarify the softening mechanism associated with molecular shift of pectic polymers and the inter- or intra-cellular movement of calcium ions induced by postharvest treatments of 1-MCP and $CO_2$.

• Food Science and Biotechnology
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• 제14권2호
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• pp.185-189
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• 2005

The effect of NaCl solution concentration (from 0 to 3 M) on the extraction of pectinesterase (PE) from jalapeno chili pepper (Capsicum annuum) was studied by determining its solubilization degree from the chili tissue. All concentrations of the salt favored the solubilization of PE in jalapeno chili pepper, compared to that in water. Maximum enzyme activity was obtained with NaCl 2.0 M. The effect of temperature on the PE activity of jalapeno chili pepper in the extracts was also studied. The PE residual activity of jalapeno pepper was 75% after 60 min of incubation at $55^{\circ}C$ and 10% at $75^{\circ}C$. At $85-95^{\circ}C$, PE residual activity was 5% after 5 min of incubation.

• 한국균학회지
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• 제16권2호
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• pp.64-69
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• 1988

사과반점낙엽병균(班點落葉病菌) Alternaria mali의 iprodione 저항성균주중(抵抗性菌株中) 병원성(病原性)이 변화(變化)된 균주( 菌株)를 구하여 pectin질(質) 분해효소(分解酵素)의 활성(活性)과 병원성(病原性)간의 관계를 알아보았다. 인공배지(人工培地)에서는 병원성(病原性)이 큰 $S_1$과 $R_3$균주(菌株)가 병원성(病原性)이 작은 $R_8$균주(菌株)보다 효소활성(酵素活性)이 높았으며 endo-polymethylgalacturonase와 endo-polygal-acturonase의 활성(活性)은 3배 이상이었다. 그러나 pectinmethylesterase와 pectin Iyase의 활성(活性)은 $S_1$균주(菌株)가 $R_3$와 $R_8$보다 높게 나타났다. 증류수(蒸溜水)로 투석(透析)시킨 사과배지(培地)에서 각 균주(菌株)는 높아진 효소활성(酵素活性)을 보였으나 균의(菌) 생장(生長)은 감소(減少)하였다. 또한 iprodione을 첨가(添加)하므로써 감수성(感受性) 균주(菌株)인 $S_1$의 효소활성(酵素活性)과 균사생장(菌絲生長)은 감소(減少)되었으나, 저항성균수(抵抗性菌洙)중 병원성(病原性)이 큰 $R_3$균주(菌株)는 투석(透析)시킨 사과배지(培地)에서 exo-polygalacturonase를 제외(除外)한 효소(酵素)의 활성(活性)이 증가(增加)되었다.

• Journal of Plant Biotechnology
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• 제43권2호
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• pp.204-212
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• 2016

환경스트레스 중의 하나인 저온에 대한 생육기의 포도나무의 반응을 분석하고자 -$2^{\circ}C$에서 4일 동안 저온처리 한두 품종('Campbell Early'와 'Muscat Baily A')의 포도나무잎을 이용하여 전사체를 분석하였고 특이발현유전자(differentially expressed genes, DEGs)를 검색하였다. 영하의 저온에 반응한 'Campbell Early'의 DEG를 기능별로 분석한 결과 생물대사에서 17,424개, 세포구성에서 28,954개, 분자기능에서는 6,972개의 유전자와 관련이 있었다. 발현이 유도되는 유전자로는 dehydrin xero 1, K-box region and MADS-box transcription factor family protein과 MYB domain protein 36이 있으며, 억제되는 유전자로는 light-harvesting chlorophyll B-binding protein 3, FASCICLIN-like arabinoogalactan 9와 pectin methylesterase 61 등이 있었다. 'Muscat Baily A'의 DEG는 생물대사에서 1,157개, 세포구성에서 1,350개, 분자기능에서는 431개의 유전자와 관련이 있었다. 발현이 유도되는 유전자로는 NB-ARC domain-containing disease resistance protein, fatty acid hydrozylase syperfamily와 isopentenyltransferase 3이 있으며, 억제되는 유전자로는 binding, IAP-like protein 1과 pentatricopeptide repeat superfamily protein 등이 있었다. Real-time PCR을 이용하여 영하의 저온에서 특이적으로 발현하는 유전자들을 검정하였으며, InterPro Scan을 통해 단백질 도메인을 분석한 결과 두 품종 모두에서 ubiquitin-protein ligase가 가장 많았다. 영하의 저온에 노출된 신초의 전사체 정보를 바탕으로 포도나무에서 저온 내성을 발현하는 기작을 연하는 데에 분자수준의 정보를 제공하고, 내한성 포도를 육종하는데 이용될 수 있을 것이다.

• The Plant Pathology Journal
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• 제35권2호
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• pp.91-99
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• 2019

Mitogen-activated protein kinase (MAPK) cascades in fungi are ubiquitously conserved signaling pathways that regulate stress responses, vegetative growth, pathogenicity, and many other developmental processes. Previously, we reported that the AbSte7 gene, which encodes a mitogen-activated protein kinase kinase (MAPKK) in Alternaria brassicicola, plays a central role in pathogenicity against host cabbage plants. In this research, we further characterized the role of AbSte7 in the pathogenicity of this fungus using ${\Delta}AbSte7$ mutants. Disruption of the AbSte7 gene of A. brassicicola reduced accumulation of metabolites toxic to the host plant in liquid culture media. The ${\Delta}AbSte7$ mutants could not efficiently detoxify cruciferous phytoalexin brassinin, possibly due to reduced expression of the brassinin hydrolase gene involved in detoxifying brassinin. Disruption of the AbSte7 gene also severely impaired fungal detoxification of reactive oxygen species. AbSte7 gene disruption reduced the enzymatic activity of cell walldegrading enzymes, including cellulase, ${\beta}$-glucosidase, pectin methylesterase, polymethyl-galacturonase, and polygalacturonic acid transeliminase, during host plant infection. Altogether, the data strongly suggest the MAPKK gene AbSte7 plays a pivotal role in A. brassicicola during host infection by regulating multiple steps, and thus increasing pathogenicity and inhibiting host defenses.

• 한국식품과학회지
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• 제47권1호
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• pp.56-62
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• 2015

본 연구에서는 식자재로서 사용 빈도는 높지만 가열에 의해 조직감 손상이 급격한 양파의 조직 연화 방지를 위해 먼저 저온가열 조리 및 레토르트와 같은 고온 가열 살균 시 일어나는 물리적 특징과 조직감 변화를 측정하고 kinetic model을 제안하여 가열연화 mechanism을 밝혔다. 가열 중 양파의 firmness 변화는 $60-80^{\circ}C$ 저온에서의 조직 경화와 $90-100^{\circ}C$ 고온에서의 기질 a, b에 의한 가열 연화를 감안한 3-mechanism model로 설명이 가능하였으며, firmness 증가를 가져오는 양파 내 PE 활성은 $70^{\circ}C$에서 가장 높았다. $70^{\circ}C$ 이하 양파 PE system의 firmness 성분 빈도인자 $K_{op}$는 $1.25{\times}10^{10}$, 활성화 에너지는 $23.25kcal/mol{\cdot}K$로서 동력학적 특성이 배추와 유사하였다(6,7). 또한 $80-100^{\circ}C$의 $H_f$의 $K_{of}$와 $Ea_f$의 값은 $6.75{\times}10^4$, $12.90kcal/mol{\cdot}K$이었으며, $H_S$의 $K_{os}$, $Ea_s$는 각각 $4.80{\times}10^4$, $13.12kcal/mol{\cdot}K$였다. 배추류 채소 Ea 값 $19-23kcal/mol{\cdot}K$과 비교 시 낮은 값이 나와 양파 조직이 배추 보다 온도 변화에 더 민감하여 빠른 시간에 손상 됨을 알 수 있었다. $121^{\circ}C$에서 가열하는 retort의 경우 초기 3분 내에 모든 세포벽 구성 물질이 동시에 거의 파괴되어 조직감 손상이 매우 큰 것으로 나타났으며, 일반적인 가열연화 기작이 적용되지 않았다. 또한 양파의 예비 열처리를 통해 펙틴의 메톡실기 분해효소인 PE의 활성을 촉진시켜 생성된 유리 카르복실기에 첨가한 $Ca^{2+}$이 cross-linkage를 형성하는 조직경화 기작을 확산과 흡착 현상으로 해석하였다. $20^{\circ}C$ 상온에서는 삼투압 차에 따른 자연 확산으로 칼슘의 이동 현상 해석이 가능하여, Fick의 비정상 상태의 확산모델이 유효하였으며, 겉보기 확산계수는 $3.83{\times}10^{-12}m^2/s$이었다. $50-90^{\circ}C$에서는 단순 삼투압 차에 PE의 활성 촉진에 의한 칼슘의 지속적인 adsorption으로 삼투압 등장 상태로의 지연 효과가 더해져 칼슘량은 $70^{\circ}C$에서 최대가 되어 $20^{\circ}C$ 보다 5.5배 증가 하였다. $80-90^{\circ}C$에서는 열변성에 의한 PE의 불활성으로 유리 carboxyl기를 생성시키지 못하여 칼슘 결합량이 감소하였다. $50-90^{\circ}C$의 칼슘 겉보기 흡착계수는 2.9-8.2(${\times}10^7$, $1/(g{\cdot}min)$)이며, $70^{\circ}C$에서 가장 높아 활발한 결합이 일어남을 알 수 있었다. 칼슘의 흡착반응 활성화 에너지는 6.44 kcal/mol로서 배추의 염절임 시 나트륨의 확산 반응 활성화 에너지 16 kcal/mol 보다 2.5배 작은 값을 보여 단순 삼투압 차에 의한 확산 반응보다 활발하게 반응이 일어남을 알 수 있었다(12,13,17). 또한 본 연구의 가열연화 기작 고찰을 통해 레토르트 처리한 양파의 조직감(견고성)을 향상시키기 위하여 $65-75^{\circ}C$, 0.3-0.5% 유산칼슘 용액에서 60-120분간 예비 열처리하는 저온 장시간(Low Temperature Long Time, LTLT) 블렌칭 방법도 확립하였다.