• Korean Journal of Organic Agriculture
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• v.6 no.2
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• pp.127-140
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• 1998

Organic farming excludes any use of the herbicide. The present paper reviews what can be done for effective weed control with existing weed control technology by farmers crop-ping paddy rice, field crops, vegetables, and fruit trees. If condition of the crop-land-al-lows diversified rotational use of the paddy land as paddy and upland field would minimize weed problem. Practising this is limited in acreage due to extremely limited governmental investment to the land for the purpose. Secondly, rotation of crops in the upland field breaking life cycles of various weeds adapted to each crop should reduce the weed problem. This is also limited as only a few crops are making the farmer profitable. In addition climate and tolerance of crops to high and low temperature. Monsoon rains and poor drainage restrict the freedom of choice. For any crop land year-round multiple cropping in denser planting shall lessen the weed problem, this multiple cropping practiced by 1960s has been abandoned due to laborshortage and increased production cost. Deep flooding the rice is impractical at present in Korean. Mulching crop with transparent, black , or combinated polyethylene sheet, hs been in-creasingly used. Progresses in development and use of mulch with allelopathic crop residues. inexpensive paper mulch, allelopathic crop residues, inexpensive paper mulch, allelopathic crop cultivar development, recently developed ex-perimental weeding machinaries, flamers, microbial herbicides, biological control organisms, soil sterilization techniques have been critically reviewed for their adoption into existing in-tegrated weeding system. Unfortunately, information on cost-benifit, and labor-benefit, for the various methods above mentioned are lacking. Urgent need for the research on rational weeding in organic farming, and herbicide low-input farming is emphasized.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.335-343
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• 2015

One of the primary concerns about the environmental risks of genetically modified (GM) crops is that they may have adverse effects on the local arthropod communities. In this study, we investigated whether the arthropod diversity and community structure in fields of GM rice tolerant to protoporphyrinogen oxidase (PPO)-inhibiting herbicides differ from those in non-GM (control) rice fields. The aim of this study was to assess the potential adverse effects of GM rice on the local arthropod communities. During the growing seasons in the study period, we collected arthropods from both fields by using yellow sticky traps and compared the diversity and community structure of arthropods from the two sites. Overall, the GM rice had no significant effect on the diversity of the local arthropod communities. In addition, multivariate analyses (permutational multivariate analysis of variance and nonmetric multidimensional scaling) showed that the structures of arthropod communities were not affected by the rice genotype (GM vs. non-GM), although these comparisons were made using data obtained at different sampling dates.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.185-189
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• 2002

Along with the worldwide rapid increase of the cultivation area and commercial production of genetically modified (GM) crops, the amount of GM grains imported to Korea has also been increasing. Roundup-Ready soybean (RRS) was introduced with 5-enolpyruvyl shikimate-3-photphate synthase (EPSPS) gene derived from Agrobacterium CP4 to confer the resistance to herbicide, glyphosate. In this study, we tried to develop PCR-based analytical method to detection the presence of RRS among non-GM soybeans. In order to detect RRS specifically, oligonucleotide primers were specifically designed based on the nucleotide sequence of EPSPS transgene. Qualitative PCR method was established and its specificity and accuracy were confirmed by analysing the nucleotide sequence of PCR DNA fragments. Bioassay was also conducted by spraying glyphosate at seedling stage. Survived individuals showed obvious resistance to Roundup Ready, however all of non-GM seedlings died in two weeks after spray. Conclusively, the highly selective detection systems for RRS were successfully established by both PCR using specific primers to EPSPS transgene and bioassay using the herbicide resistance of RRS. In addition to, the imported soybean showed to be mixed to several varieties regarding to 100-seed weight and hilum color.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.40-45
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• 2020

Over 500 genetically modified organisms (GMOs) have been developed since 1996, of which nearly 44% have glufosinate herbicide-tolerant traits. Identification of specific markers that can be used to identify herbicide-tolerant traits is challenging as the DNA sequences of the gene(s) of a trait are highly variable depending on the origin of the gene(s), plant species, and developers. To develop specific PCR marker(s) for the detection of the glufosinate-tolerance trait, DNA sequences of several pat or bar genes were compared and a diverse combination of PCR primer sets were examined using certified reference materials or transgenic plants. Based on both the qualitative and quantitative PCR tests, a primer set specific for pat and non-specific for bar was developed. Additionally, a set of markers that can detect both pat and bar was developed, and the quantitative PCR data indicated that the primer pairs were sensitive enough to detect 0.1% of the mixed seed content rate.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.8-15
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• 1994

The mode of safening action and potency of the 1, 8-naphthalic anhydride(NA) were investigated in corn(Zea mays) and soybean(Glycine max) treated with herbicide bensulfuron[2-{{{{{(4,6-dimethoxy-2-pyrimidinyl)amino}carbonyl}amino}sulfonyl}methyl}benzoic acid] and imazaquin[2-{4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl} 3-quinolinonecarboxylic acid]. Seed dressing with 0.2%(w/w) NA showed successful protection in corn against injury from herbicide bensulfuron and imazaquin but not in soybean. Safening factors of NA against bensulfuron and imazaquin were 10.2 and 5.0, respectively, in corn, while they were both 1.3 in soybean. In vivo, Glutathione-S-transferase(GST) activity of NA-treated corn and soybean increased 1.8-and 1.3-fold, respectively, but the activity was not affected by the herbicides in vitro. Acetolactate synthase(ALS) levels of NA-treated corn was increased 1.3-fold, but not changed in soybean. Tolerance of ALS activity to the herbicides was slightly greater in ALS obtained from NA-treated corn than that from the untreated, whereas the difference was not found in soybean. A significant increase of ACCase due to NA occurred in corn, but not in soybean. The herbicides did not affect in vitro ACCase activity.

• Journal of Plant Biotechnology
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• v.50
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• pp.56-62
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• 2023

Transgenic lilies have been obtained using Agrobacterium tumefaciens (AGL1) with the plant scale explants, followed by DL-phosphinothricin (PPT) selection. In this study, scales of lily plants cv. "red flame" were transformed with the pCAMBIA3301 vector containing the gus gene as a reporter and the blpR gene as a selectable marker, as well as a gene of interest showing herbicide tolerance, both driven by the CaMV 35S promoter. Using a 20-minute infection time and a 5-day cultivation period, factors that optimized and demonstrated a high transformation efficiency were achieved. With these conditions, approximately 22-27% efficiency was observed for Agrobacterium-mediated transformation in lilies. After transformation with Agrobacterium, scales of lilies were transferred to MS medium without selective agents for 2 weeks. They were then placed on selection MS medium containing 5 mg/L PPT for a month of further selection and then cultured for another 4-8 weeks with a 4-week subculture regime on the same selection medium. PPT-resistant scales with shoots were successfully rooted and regenerated into plantlets after transferring into hormone-free MS medium. Also, most survived putatively transformed plantlets indicated the presence of the blpR gene by PCR analysis and showed a blue color indicating expression of the gus gene. In conclusion, when 100 scales of lily cv. "red flame" are transformed with Agrobacterium, approximately 22-27 transgenic plantlets can be produced following an optimized protocol. Therefore, this protocol can contribute to the lily breeding program in the future.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.191-200
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• 1986

The study was conducted to screen paraquat-tolerant plant species among crops and weeds, using the response of plant like leaf disc discoloration, visual injury and dry weight in the presence of paraquat. Mechanism of paraquat-tolerance was investigated in strains of soybean through evaluating activities of superoxide dismutase and peroxidase and the multiplication of callus derived from soybean cotyledon. In crops, Kwanggyo has been selected as a paraquat-tolerant variety among soybean cultivars tested, and Hood as a susceptible one. In weeds, Polygonum aviculare, Chenopodium album and Pinellia ternata were evaluated as the paraquat resistant species, providing the possibility for the donor plant species for paraquat resistance. Activity of superoxide dismutase known to detoxify paraquat was markedly greater in Kwanggyo, a paraquat-tolerant cultivar than in Hood, a susceptible one. In addition, the similar response like superoxide dismutase was observed in peroxidese activity. The greater inhibition of callus multiplication was determined in Hood, a susceptible one than a tolerant one, Kwnggyo. Based on all the informations, it is strongly proposed that paraquat tolerance in soybean is due to destruction of $O_2^-$ by elevated concentration of superoxide dismutase in the tolerant cultivar.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1130-1134
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• 2005

To monitor the possibility of horizontal gene transfer between transgenic potato and bacteria in the environment, the gene flow from glufosinate-tolerant potato to bacteria in soils was investigated. The soil samples treated with the leaf tissue of either glufosinate-tolerant or glufosinate-sensitive potato were subjected to PCR and Southern hybridization to determine possible occurrence of glufosinate-resistant soil bacteria and to detect the bar (phosphinothricin acetyltransferase) gene, conferring tolerance to glufosinate. The bar gene was not detected from genomic DNAs extracted at different time intervals from the soil samples, which had been treated with the leaf tissue of either transgenic or non-transgenic potato for 2 to 8 weeks. In addition, the level of glufosinate-resistant bacteria isolated from the soil samples treated with the leaf tissue of transgenic potato was similar to that of the samples treated with non-transgenic potato after 4 months of incubation at $25^{\circ}C$. The bar gene was not detected in the genomic DNAs extracted from colonies growing on the plate containing glufosinate, indicating that the bacteria could acquire the resistant phenotype to glufosinate by another mechanism without the uptake of the bar gene from glufosinate-tolerant potato.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1162-1169
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• 2014

Glyphosate is the active component of the top-selling herbicide, the phytotoxicity of which is due to its inhibition of the shikimic acid pathway. 5-Enolpyruvylshikimate-3-phosphate synthase (EPSPS) is a key enzyme in the shikimic acid pathway. Glyphosate tolerance in plants can be achieved by the expression of a glyphosate-insensitive aroA gene (EPSPS). In this study, we used a PCR-based two-step DNA synthesis method to synthesize a new aroA gene ($aroA_{R.\;leguminosarum}$) from Rhizobium leguminosarum. In vitro glyphosate sensitivity assays showed that $aroA_{R.\;leguminosarum}$ is glyphosate tolerant. The new gene was then expressed in E. coli and key kinetic values of the purified enzyme were determined. Furthermore, we transformed the aroA gene into Arabidopsis thaliana by the floral dip method. Transgenic Arabidopsis with the $aroA_{R.\;leguminosarum}$ gene was obtained to prove its potential use in developing glyphosate-resistant crops.

• Korean Journal of Medicinal Crop Science
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• v.12 no.5
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• pp.360-365
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• 2004

Rehmannia glutinosa shows a high level of resistance to the non-selective herbicide paraquat. To characterize the antioxidant enzyme system of R. glutinosa, we comparatively examined the responses of antioxidant enzymes to UV, wounding and a general elicitor yeast extract in R. glutinosa and soybean. The levels of enzyme activities of the two plant species were drastically different between those per fresh weight (general activity) and per protein (specific activity) bases. The general activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and glutathione reductase (GR) were lower, but that of ascorbate peroxidase (APX) was higher in R. glutinosa than in soybean. The specific activities of the enzymes, however, were about two- to seven-fold higher in R. glutinosa than in soybean, except that of CAT, which was about 12-fold higher in soybean. The general and specific enzyme activities of R. glutinosa relative to those of soybean showed a consistent increase in responses to the stresses only in SOD. The specific activities of SOD and APX were higher in R. glutinosa in all stress treatments. The results might suggest a relatively higher contribution of SOD and APX to the stress tolerance.