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  • ReviewSeptember 30, 2015

    2 647 2126

    Biosynthetic pathway of shikimate and aromatic amino acid and its metabolic engineering in plants

    Sun-Hyung Lim, Sang Kyu Park, Sun-Hwa Ha, Min Ji Choi, Da-Hye Kim, Jong-Yeol Lee, and Young-Mi Kim

    Journal of Plant Biotechnology 2015; 42(3): 135-153

    https://doi.org/10.5010/JPB.2015.42.3.135

    Abstract

    Abstract : The aromatic amino acids, which are composed of ?-phenylalanine, ?-tyrosine and ?-tryptophan, are general components of protein synthesis as well as precursors for a wide range of secondary metabolites. These aromatic amino acids-derived compounds play important roles as ingredients of diverse phenolics including pigments and cell walls, and hormones like auxin and salicylic acid in plants. Moreover, they also serve as the natural products of alkaloids and glucosinolates, which have a high potential to promote human health and nutrition. The biosynthetic pathways of aromatic amino acids share a chorismate, the common intermediate, which is originated from shikimate pathway. Then, tryptophan is synthesized via anthranilate and the other phenylalanine and tyrosine are synthesized via prephenate, as intermediates. This review reports recent studies about all the enzymatic steps involved in aromatic amino acid biosynthetic pathways and their gene regulation on transcriptional/post-transcriptional levels. Furthermore, results of metabolic engineering are introduced as efforts to improve the production of the aromatic amino acids-derived secondary metabolites in plants.

  • ReviewSeptember 30, 2015

    0 181 1052

    An efficient gene targeting system using homologous recombination in plants

    Yong-Ik Kwon, and Hyo-Yeon Lee

    Journal of Plant Biotechnology 2015; 42(3): 154-160

    https://doi.org/10.5010/JPB.2015.42.3.154

    Abstract

    Abstract : The plant breeding technology was developed with genetic engineering. Many researchers and breeders have turned from traditional breeding to molecular breeding. Genetically modified organisms (GMO) were developed via molecular breeding technology. Currently, molecular breeding technologies facilitate efficient plant breeding without introducing foreign genes, in virtue by of gene editing technology. Gene targeting (GT) via homologous recombination (HR) is one of the best gene editing methods available to modify specific DNA sequences in genomes. GT utilizes DNA repair pathways. Thus, DNA repair systems are controlled to enhance HR processing. Engineered sequence specific endonucleases were applied to improve GT efficiency. Engineered sequence specific endonucleases like the zinc finger nuclease (ZFN), TAL effector nuclease (TALEN), and CRISPR-Cas9 create DNA double-strand breaks (DSB) that can stimulate HR at a target site. RecQl4, Exo1 and Rad51 are effectors that enhance DSB repair via the HR pathway. This review focuses on recent developments in engineered sequence specific endonucleases and ways to improve the efficiency of GT via HR effectors in plants.

  • ReviewSeptember 30, 2015

    6 231 1064

    Current status of sweetpotato genomics research

    Ung-Han Yoon, Jae Cheol Jeong, Sang-Soo Kwak, Jung-Wook Yang, Tae-Ho Kim, Hyeong-Un Lee, Sang-Sik Nam, and Jang-Ho Hahn

    Journal of Plant Biotechnology 2015; 42(3): 161-167

    https://doi.org/10.5010/JPB.2015.42.3.161

    Abstract

    Abstract : Sweetpotato [Ipomoea batatas (L.) Lam] grows well in harsh environmental conditions, and is cultivated as one of the top seven food crops in the world. Recently, sweetpotato is drawing interest from people as a healthy food because it is high in dietary fiber, vitamins, carotenoids and overall nutrition value. However, few studies have been conducted on sweetpotato genome sequencing in spite of its importance. This review is aimed at increasing the efficiency of sweetpotato genome sequencing research as well as establishing a base for gene utilization in order to control useful traits. Recently, animal and plant genome sequencing projects increased significantly. However, sweetpotato genome sequencing has not been performed due to polyploidy and heterogeneity problems in its genome. Meanwhile research on its transcriptome has been conducted actively. Recently, a draft of the diploid sweetpotato genome was reported in 2015 by Japanese researchers. In addition, the Korea-China-Japan Trilateral Research Association of Sweetpotato (TRAS) has conducted research on gene map construction and genome sequencing of the hexaploid sweetpotato Xushu 18 since 2014. The Bill & Melinda Gates Foundation launched the ‘sweetpotato genomic sequencing to develop genomic tools for Sub-Sahara Africa breeding program’. The chloroplast genome sequence acquired during sweetpotato genome sequencing is used in evolutionary analyses. In this review, the trend of research in the sweetpotato genome sequencing was analyzed. Research trend analysis like this will provide researchers working toward sweetpotato productivity and nutrient improvement with information on the status of sweetpotato genome research. This will contribute to solving world food, energy and environmental problems.

  • Research ArticleSeptember 30, 2015

    3 209 943

    Alteration of plant hormones in transgenic rice (Oryza sativa L.) by overexpression of anti-apoptosis genes during salinity stress

    Mohammad Ubaidillah, Fika Ayu Safitri, Sangkyu Lee, Gyu-Hwan Park, and Kyung-Min Kim

    Journal of Plant Biotechnology 2015; 42(3): 168-179

    https://doi.org/10.5010/JPB.2015.42.3.168

    Abstract

    Abstract : We previously identified the rice gene, OsSAP, as an encoder of a highly conserved putative senescence-associated protein that was shown to have anti-apoptotic activity. To confirm the role of OsSAP in inducing abiotic stress tolerance in rice, we introduced OsSAP and AtBI-1, a plant homologue of Bax inhibitor-1, under the control of the CaMV 35S promoter into the rice genome through Agrobacterium-mediated transformation. The OsSAP transformants showed a similar chlorophyll index after salinity treatments with AtBI-1. Furthermore, we compared the effects of salinity stress on leaves and roots by examining the hormone levels of abscisic acid (ABA), jasmonic acid (JA), gibberellic acid (GA3), and zeatin in transformants compared to the control. With the exception of phytohormones, stress-induced changes in hormone levels putatively related to stress tolerance have not been investigated previously. Hormonal level analysis confirmed the lower rate of stress in the transformants compared to the control. The levels of ABA and JA in OsSAP and AtBI-1 transformants were similar, where stress rates increased after one week and decreased after a two week period of drought; there was a slightly higher accumulation compared to the control. However, a similar trend was not observed for the level of zeatin, as the decrease in the level of zeatin accumulation differed in both OsSAP and AtBI-1 transformants for all genotypes during the early period of salinity stress. The GA3 level was detected under normal conditions, but not under salinity stress.

  • Research ArticleSeptember 30, 2015

    2 149 989

    Development of transgenic strawberry plants expressing monellin, a sweet protein

    Sung Ran Min, Suk Min Ko, Jae Il Lyu, Ji Hyun Park, So Young Yi, In-Ha Lee, Hyun Sook Kim, Tae Il Kim, Pil Son Choi, Won-Joong Jeong, Suk Weon Kim, Jonghyun Kim, and Jang R. Liu

    Journal of Plant Biotechnology 2015; 42(3): 180-185

    https://doi.org/10.5010/JPB.2015.42.3.180

    Abstract

    Abstract : Leaf discs from ‘Yeobong’ and ‘Maehyang’ strawberry plants were used as explants for transformation. The Agrobacterium tumefaciens strain EHA105 harboring the monellin gene under the control of the CaMV 35S promoter was used in co-cultivation experiments. The frequencies of callus formation and plant regeneration from leaf explants after co-cultivation in ‘Yeobong’ were higher than those of ‘Maehyang’. These transgenic plants showed normal growth patterns and flowering. PCR and Southern hybridization confirmed that 1 to 2 copies of the monellin gene were integrated into genome of the transgenic strawberry plants. Northern blot analysis confirm that the transcripts were expressed in transgenic strawberry plants. Although long-term subcultured transgenic strawberry plants showed a phenomenon to escape the transgene, the transformation system established in this study provides new opportunities for genetic improvement of strawberry plants.

  • Research ArticleSeptember 30, 2015

    2 196 897

    Development of high tryptophan GM rice and its transcriptome analysis

    Yu Jin Jung, Franz Marielle Nogoy, Yong-Gu Cho, and Kwon Kyoo Kang

    Journal of Plant Biotechnology 2015; 42(3): 186-195

    https://doi.org/10.5010/JPB.2015.42.3.186

    Abstract

    Abstract : Anthranilate synthase (AS) is a key enzyme in the biosynthesis of tryptophan (Trp), which is the precursor of bioactive metabolites like indole-3-acetic acid and other indole alkaloids. Alpha anthranilate synthase 2 (OsASA2) plays a critical role in the feedback inhibition of tryptophan biosynthesis. In this study, two vectors with single (F124V) and double (S126F/L530D) point mutations of the OsASA2 gene for feedback-insensitive α subunit of rice anthranilate synthase were constructed and transformed into wildtype Dongjinbyeo by Agrobacterium-mediated transformation. Transgenic single and double mutant lines were selected as a single copy using TaqMan PCR utilized nos gene probe. To select intergenic lines, the flanking sequence of RB or LB was digested with a BfaI enzyme. Four intergenic lines were selected using a flanking sequence tagged (FST) analysis. Expression in rice (Oryza sativa L.) of the transgenes resulted in the accumulation of tryptophan (Trp), indole-3-acetonitrile (IAN), and indole-3-acetic acid (IAA) in leaves and tryptophan content as a free amino acid in seeds also increased up to 30 times relative to the wildtype. Two homozygous event lines, S-TG1 and D-TG1, were selected for characterization of agronomic traits and metabolite profiling of seeds. Differentially expressed genes (DEGs), related to ion transfer and nutrient supply, were upregulated and DEGs related to co-enzymes that work as functional genes were down regulated. These results suggest that two homozygous event lines may prove effective for the breeding of crops with an increased level of free tryptophan content.

  • Research ArticleSeptember 30, 2015

    5 172 993

    Establishment of detection methods for approved LMO in Korea

    Min-A Seol, Jung Ro Lee, Wonkyun Choi, Beom-Ho Jo, Jeong Chan Moon, Su Young Shin, Soon-Jae Eum, Il Ryong Kim, and Hae-Ryong Song

    Journal of Plant Biotechnology 2015; 42(3): 196-203

    https://doi.org/10.5010/JPB.2015.42.3.196

    Abstract

    Abstract : Living modified organisms (LMO) are one of the most widespread products of modern biotechnology after DNA discovery. Due to the decline of grain self-sufficiency rate and the increase of reliance on LMO imports in Korea, a series of concerns with regard to safety of living modified(LM) crops has been raised. The aim of this study is to establish the detection methods for unintentional release or growing of LMO plants in environmental conditions. To detect LM crop events, general concepts of specific primer design and PCR conditions were provided by the Joint Research Centre (JRC). The certified reference materials of seven LM events (4 soybean, 2 cotton and 1 corn) were obtained from the Institute for Reference Materials and Measurements (IRMM) and the American Oil Chemists’ Society (AOCS). Genomic DNA from seven LM events were purified and PCR amplifications were carried out by using individual event-specific primer sets. LM-specific PCR products of all seven events were efficiently amplified by our methods. The results indicate that the established detection method for LMOs is suitable as a scientific tool to monitor whether the crops found in natural environments are LMOs.

  • Research ArticleSeptember 30, 2015

    0 149 795

    Effects of Brassica rapa SHI-RELATED SEQUENCE overexpression on petunia growth and development

    Joon Ki Hong, Eun Jung Suh, Su Young Lee, Cheon Young Song, Seung Bum Lee, Jin A Kim, Soo In Lee, and Yeon-Hee Lee

    Journal of Plant Biotechnology 2015; 42(3): 204-214

    https://doi.org/10.5010/JPB.2015.42.3.204

    Abstract

    Abstract : SHI-RELATED SEQUENCE (SRS) genes are plant-specific transcription factors that contain a zinc-binding RING finger motif, which play a critical role in plant growth and development. Among Brassica rapa SRS genes, BrSRS7 and BrLRP1 genes, isolated from shoot apical regions are important regulators of plant growth and development. In order to explore the function of BrSRS genes in horticultural plant growth and development, two constructs containing BrSRS7 and BrLRP1 under the control of a cauliflower mosaic virus 35S promoter were introduced into petunia by Agrobacterium-mediated transformation. The resulting transgenic plants were dwarf and compact plants with reduced plant height and diameter. Additionally, these transgenic plants had upward-curled leaves of narrow width and short internodes. Interestingly, the flower shapes of petunia were different among transgenic plants harboring different kinds of SRS genes. These phenotypes were stably inherited through generations T2 and T3. Semi-quantitative RT-PCR analyses of transgenic plants revealed that BrSRS7 and BrLRP1 regulate expression of gibberellin (GA)- and auxin-related genes, PtAGL15- and PtIAMT1-related, involved in shoot morphogenesis. These results indicate that the overexpression of BrSRS7 and BrLRP1 genes suppressed the growth and development of petunia by regulating expression of GA- and auxin-related genes. From these data, we deduce that BrSRS7 and BrLRP1 genes play an important role in the regulation of plant growth and development in petunia. These findings suggest that transformation with the BrSRS genes can be applied to other species as a tool for growth retardation and modification of plant forms.

  • Research ArticleSeptember 30, 2015

    1 191 1021

    Physiological and molecular characterization of two inbred radish lines with different bolting times

    Hyun Ji Park, Won Yong Jung, Sang Sook Lee, Joo won Lee, Youn-Sung Kim, and Hye Sun Cho

    Journal of Plant Biotechnology 2015; 42(3): 215-222

    https://doi.org/10.5010/JPB.2015.42.3.215

    Abstract

    Abstract : The radish (Raphanus sativus L.) is an important Brassicaceae root vegetable crop worldwide. Several studies have been conducted concerning radish breeding. There are major challenges to prevent premature bolting in spring plantings. Here, we performed the characterization of two inbred radish lines which vary in bolting time. “Late bolting radish” (NH-JS1) and “early bolting radish” (NH-JS2) were generated by a conventional breeding approach. The two inbred lines showed different bolting phenotypes depending on vernalization time at 4°C. NH-JS1, the late bolting radish, was less sensitive to cold treatment and the less sensitivity was inversely proportional to the duration of the vernalization. We also measured gene expression levels of the major bolting time related genes in the NH-JS1 and NH-JS2 lines. RsFLC1 plays a central role in the timing of flowering initiation. It is a strong repressor and it’s transcript is highly expressed in NH-JS1 compared to NH-JS2 under no treatment and vernalization conditions. RsFRI, a positive regulator of RsFLC, is also highly expressed in NH-JS1 compared to NH-JS2 regardless of vernalization. In contrast, RsSOC1, suppressed by FLC as a floral integrator gene, showed the most difference, a 5-fold increase, between NH-JS1 and NH-JS2 under vernalization conditions. From these results, we conclude that NH-JS1 showed a late flowering phenotype after cold treatment due to the expression differences of flowering time regulator genes rather than difference sensitivity to cold. These results may be useful to understand the control mechanisms of flowering time and may help identify molecular markers for selecting late bolting trait in radish.

  • Research ArticleSeptember 30, 2015

    11 170 849
    Abstract

    Abstract : Embryogenic callus (EC) was created from mature embryos of Larix kaempferi. With the mature embryos, keeping the culture in dark conditions throughout the experiment (38.2%) seemed to give better results than exposing them to 16 h light (25 μEm-2s-1) for the first week (21.9%). EC was obtained most frequently from Quoirin and Lepoivre (LP) mediums with 1.0 mg/L 4-amino-3,5,6-trichloropicolinic acid (Picloram), plus 1.0 mg/L benzyladenine (BA) (62.8%) or Litvay’s medium (LM) containing 1.0 mg/L p-chlorophenoxyacetic acid (pCPA) plus 1.0 mg/L BA (62.8%) treatment. In both cases, best results were obtained when zygotic embryos were cultured in darkness. As for the effective sucrose concentration on initiation of EC, 29.2 mM sucrose (38.6%) gave the best results.

JPB
Vol 51. 2024

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pISSN 1229-2818
eISSN 2384-1397
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