• The Plant Pathology Journal
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• v.35 no.5
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• pp.406-416
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• 2019

Strawberry, an important fruit crop, is susceptible to a large number of pathogens that reduce fruit quality and productivity. In this study, the effect of a biostimulant prepared from Ascophyllum nodosum extract (ANE) (0.1%, 0.2%, and 0.3%) was evaluated on powdery mildew progression under greenhouse and field conditions. In the greenhouse, application of 0.2% ANE showed maximum reduction in powdery mildew progression as compared to the control. Forty-eight hour post-inoculation, foliar spray of 0.2% ANE reduced spore germination by 75%. Strawberry leaves sprayed with ANE showed higher total phenolic and flavonoid content in response to powdery mildew infection. Furthermore, application of ANE elicited defense response in strawberry plants by induction of defense-related enzymes, such as phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase activity. In field conditions, foliar spray of 0.2% ANE showed a reduction of 37.2% of natural incidence of powdery mildew infection as compared to the control. ANE sprayed plant also reduces the severity of powdery mildew infection under natural conditions. These results indicate that application of ANE induces the strawberry plant's active defense against powdery mildew infection by induction of secondary metabolism and regulating the activities of defense-related enzymes.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.975-982
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• 2017

Curcumin, a hydrophobic polyphenol derived from the rhizome of the herb Curcuma longa, possesses diverse pharmacological properties, including anti-inflammatory, antioxidant, antiproliferative, and antiangiogenic activities. Two curcuminoids (dicinnamoylmethane and bisdemethoxycurcumin) were synthesized from glucose in Escherichia coli. PAL (phenylalanine ammonia lyase) or TAL (tyrosine ammonia lyase), along with Os4CL (p-coumaroyl-CoA ligase) and CUS (curcumin synthase) genes, were introduced into E. coli, and each strain produced dicinnamoylmethane or bisdemethoxycurcumin, respectively. In order to increase the production of curcuminoids in E. coli, the shikimic acid biosynthesis pathway, which increases the substrates for curcuminoid biosynthesis, was engineered. Using the engineered strains, the production of bisdemethoxycurcumin increased from 0.32 to 4.63 mg/l, and that of dicinnamoylmethane from 1.24 to 6.95 mg/l.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.203-204
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• 2013

Phenylalanine Ammonia Lyase (PAL)는 phenylalanine의 산성도가 더 큰 ammonium hydrogen 과는 반응하지 않고 그것의 nonacidic ${\beta}$ proton을 제거하는 역할을 한다. Phenylalanine은 electrophilic 그룹을 갖고 있으며 지난 30 여년 동안 phenylalanine의 electrophilic 그룹이 PAL의 반응 기작에 중요한 역할을 한다고 믿어왔다. 그러나 최근 X-ray와 UV spectroscopy를 통하여 상당히 electrophilic 한 5-methylene-3,5-dihydroimidazol-4-one (MIO) 그룹이 발견되었다. 이전의 연구들은 실험을 통하여 MIO와 관련된 electrophile에 의한 Friedel-Crafts Attack 메커니즘과 electrophile에 대한 nucleophilic addition 메커니즘을 제시하였으며, 본 연구진은 양자계산을 통하여 두 가지 메커니즘의 에너지 차이를 살펴봄으로써 더욱 합리적인 메커니즘을 제시, 규명하고자 한다. 본 연구에서는 특히 electrophile에 대한 nucleophilic addition 메커니즘에 대하여 양자계산을 이용하여 반응물, 생성물, 전이상태의 분자 구조를 제시하고 반응이 일어나는데 필요한 에너지를 계산하고자 한다.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.622-629
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• 2010

Biosynthetic studies on brasiliamides, potently convulsive and bacteriostatic compounds from an endophytic Penicillium brasilianum isolated from Melia azedarach (Meliaceae), confirms their phenylpropanoid origin, which is very uncommon in fungi. Feeding experiments with [$2-^{13}C$]-phenylalanine indicated the incorporation of two units of this amino acid on brasiliamide structures. The first step in the phenylpropanoid pathway to those compounds was evaluated through enzymatic bioassays and confirmed the phenylalanine ammonia-lyase (PAL) participation. The metabolism of phenylalanine in this fungus is discussed.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.293-300
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• 2005

The possible role of nitric oxide (NO)-induced cell division was investigated to explain the physiologycal effects of a NO donor, sodium nitroprusside (SNP) on the growth of primary leaves in chinese cabbage seedling plants. Exogenous treatment of SNP to chinese cabbage plants for 8 days at different concentrations (0, 200, 500 and 1000 ${\mu}M$) affected the leaf growth in a concentration-dependent manner, showing a maximum growth at $200\;{\mu}M$. In accordance with leaf growth responses, the chlorophyll and soluble protein contents increased strongly to 142% and 134% of control at $200\;{\mu}M$ SNP, respectively. However, a very little decrease in chlorophyll and a 13%> decrease in protein were observed at $1000\;{\mu}M$ SNP. In addition, the content of DNA and RNA also increased maximumly to 142% and 139% of the control at $200\;{\mu}M$ SNP, respectively, whereas they decreased to 80% and 84% of the control at $1000\;{\mu}M$ SNP. With respect to the development of enzymes related to cell wall synthesis, $200\;{\mu}M$ SNP led to the maximum activities in both phenylalanine ammonia-lyase (212% of the control) and guaiacol peroxidase (134% of the control). However, the activities of both enzymes were not modified significantly at $1000\;{\mu}M$ SNP. In conclusion, these results suggest that the enhancement of leaf growth in chinese cabbage plants by SNP at the effective concentration was probably due to the NO ability in the induction of cell division.

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.41-47
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• 1999

Phenylalanine ammonia-lyase (PAL; EC 4, 3, 1, 5) genomic clones were isolated from tomato(Lycopersicon esculentum L.) genomic DNA libraries using tomato PAL5 cDNA sequences as probes. The nucleotide sequences of tPAL1, tPAL4 and tPAL5 were compared. tPAL5 contains an open reading frame encoding a polypeptide of 722 amino acids, interrupted by a 710 bp intron in the codon for the amino acid 139. tPAL1 encodes a polypeptide of 249 amino acids which is much shorter than tPAL5 gene due to a premature stop codon and does not contain an intron. tPAL4 encodes a polypeptide of 357 amino acids, interrupted by a 305 bp intron in the codon for the amino acid 138. Premature stop codons observed in tPAL1 and tPAL4 gene produce a short polypeptide rather than a normal polypeptide (722 aa). tPALl shows 87.2% homology with tPAL4 and 85.3% homology with tPAL5 gene whereas tPAL4 showes 91.4% homology with tPAL5 at nucleotide level. In general, phylogenetic analysis showed that genes isolated from tomato, potato, and sweet potato were belong to the same group and another dicot plants such as parsley, bean, soybean, pea and alfalfa formed another group. PAL genes isolated from rice and yeast showed very low homology with other PAL genes and formed the other group.

• Journal of Life Science
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• v.12 no.3
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• pp.274-280
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• 2002

The metabolites related to phenylpropanoid pathway play an important role in the self-defense of plants and induced by environmental stress like wounding, pathogen attack, UV-irradiation and so on. The mRNA level of rite phenylalanine ammonia lyase (PAL) was increased at 12 h to 48 h, however it was gradually decreased 48 h to 60 h after UV irradiation. The PAL enzyme activities in rice were peaked at the time of 24 h after UV irradiation, on the other hand, it was not affected by wounding. The PAL enzyme activities in pepper were raised high at 24 h and 10 h by UV irradiation and wounding respectively. The cinnamic acid 4-hydroxylase (C4H) activities were increased by wounding treatment and were detected from 12 h to end time point of experiment, while UV-irradiation didn't affect the C4H activity in rice and pepper. These results were assumed that the action of isoflavonid has an alternative effect on the defenses which include wounding and UV irradiation and on the diverse roles in rice and hot pepper.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.6-12
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• 2012

Early growth, pigmentation, protein content, and phenylalanine ammonia-lyase (PAL) activity of red curly lettuces (Lactuca sativa L.) grown under different lighting conditions were investigated. Fluorescent lamps (control), blue, red, and blue plus red light-emitting diodes (LEDs) were used as light sources for 10 days. An equal proportion (1:1) of blue and red LEDs was used in the mixed radiation condition. Compared with the control, monochromic red or blue lighting increased fresh and dry weights of 'Ttuksum' and 'Jaju' lettuces. Anthocyanin synthesis was also significantly promoted by the mixed radiation of blue and red LEDs. The mixed radiation also increased the protein content and PAL enzyme activity of 'Ttuksum' leaves by about 200% compared to other treatments. Anthocyanin content was the highest in lettuces subjected to the mixture radiation of blue and red light treatment, while anthocyanin synthesis was inhibited by monochromic red light. The results of the present study indicate that growth and pigment synthesis in lettuces are significantly enhanced by exposure to mixed radiation from blue and red LEDs.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.1
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• pp.15-20
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• 2014

To investigate lignification process and its physiological significance under water-deficit condition, the responses of peroxidases, polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) in relation to leaf water status to the short term of water deficit treatment in the leaves with different maturities in forage rape were measured. The significant decrease in relative water content (RWC) and leaf osmotic potential (${\Psi}{\pi}$) were apparent after 5 d of water-deficit treatment. The activity of guaiacol peroxidase (GPOD), ascorbate peroxidase (APOD), coniferyl alcohol peroxidase (CPOD), and syringaldazine peroxidase (SPOD) was depressed especially in middle and old leaves when compared with that of control leaves. On the other hand, in young leaves, a significant increase in CPOD (+34%) and SPOD (+24%) activity as affected by water-deficit treatment was apparent. The activation of PAL and PPO was observed in middle and old leaves for PAL and in young and middle leaves for PPO. These results suggest that peroxidases in middle and old leaves did not involve in lignification under mild water-deficit stress, whereas CPOD and SPOD in young leaves participate in lignification by a coordination with PAL and PPO to incorporate phenol and lignin into the cell walls.

• The Plant Pathology Journal
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• v.35 no.4
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• pp.330-340
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• 2019

The present study was undertaken to evaluate the integrated effect of zinc (Zn) with other nutrients in managing early blight (EB) disease in tomato. A pot experiment was carried out with basal application of the recommended level of macronutrients [nitrogen, phosphorus and potassium (NPK)] and micronutrients [magnesium (Mg) and boron (B)] in bilateral combination with Zn (2.5 and 5.0 mg/kg) in a completely randomized deigned in replicates. Results revealed that interactive effect of Zn with Mg or B was often futile and in some cases synergistic. Zn with NPK yield synergistic outcome, therefore EB disease was managed significantly (disease incidence: 25% and percent severity index: 13%), which resulted in an efficient signaling network that reciprocally controls nutrient acquisition and uses with improved growth and development in a tomato plant. Thus, crosstalk and convergence of mechanisms in metabolic pathways resulted in induction of resistance in tomato plant against a pathogen which significantly improved photosynthetic pigment, total phenolics, total protein content and defense-related enzymes [superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL)]. The tremendous increase in total phenolics and PAL activity suggesting their additive effect on salicylic acid which may help the plant to systemically induce resistance against pathogen attack. It was concluded that interactive effect of Zn (5.0 mg/kg) with NPK significantly managed EB disease and showed positive effect on growth, physiological and biochemical attributes therefor use of Zn + NPK is simple and credible efforts to combat Alternaria stress in tomato plants.