• 농업과학연구
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• 제44권1호
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• pp.1-15
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• 2017

In major field crops, synthetic herbicides have been used to control weeds worldwide. Globally, herbicide resistance in weeds should be minimized because it is a major limiting factor for food security. Cross resistance can occur with herbicides within the same or in different herbicide families and with the same or different sites of action. Multiple resistance refers to evolved mechanisms of resistance to more than one herbicide (e.g., resistance to both ALS-inhibitors and ACCase-inhibitors) and this resistance was brought about by separate selection processes. Target site resistance could occur from changes at the biochemical site of action of one herbicide. Non target site resistance occurs through mechanisms which reduce the number of herbicide molecules that reach the herbicide target site. There are currently 480 unique cases (species ${\times}$ site of action) of herbicide resistance globally in 252 plant species (145 dicots and 105 monocots). To date, resistance in weeds has been reported to 161 different herbicides, involving 23 of the 26 known herbicide sites of action. Finally, it can be concluded that we can protect crops associated to herbicide resistant weeds by applications of biochemical, genetic and crop control strategies.

• 농업과학연구
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• 제46권2호
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• pp.405-416
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• 2019

Weeds are a serious problem in crop production. Use of synthetic herbicides is rapidly increasing in weed management worldwide including Korea. Herbicide application reduces the time spent on weed control. However, the evolution of resistance to herbicides in weeds has become widespread as a natural response to selection pressure imposed by agricultural management activities. If an herbicide with the same mechanisms of action is used repeatedly and intensively, it can rapidly select for a weed biotype that shifts toward difficult-to-control becoming a more tolerant weed and lead to the evolution of herbicideresistant weeds. Moreover, agricultural and biological factors have an important role in the development of herbicide-resistant weed populations. Mitigating the evolution of herbicide resistance in weeds relies on reducing selection through the diversification of weed control techniques. The resistance management of weeds in the future will strongly depend on intensive cropping systems. The current situation of intensive cropping systems with their heavy reliance on the efficacy of chemical weed control will not lead to significant containment of this problem. Therefore, management strategies need to overcome the further spread of herbicide resistance in weeds in Korean crop production. This review presents the current information on herbicide resistance in Korea and factors controlling the development of herbicide resistant weeds.

• Weed & Turfgrass Science
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• 제6권1호
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• pp.28-31
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• 2017

The mutation rate of proline in the position 197 (Pro197) in acetohydroxy acid synthase (AHAS) is highest among sulfonylurea (SU) herbicide-resistance mutants. Therefore, it is significant to investigate the resistance mechanism for the mutation and to develop the herbicides specific to the mutants. SU herbicide resistance mechanism of the mutants, 197Ser, 197Thr and 197Ala, in AHAS were targeted for designing new SU-herbicide. We did molecular dynamics (MD) simulation for understanding SU herbicide-resistance mechanisms of AHAS mutants and designed new herbicides with docking and MD evaluations. We have found that mutation to 197Ala and 197Ser enlarged the entrance of the active site, while 197Thr contracted. Map of the root mean square derivation (RMSD) and radius gyrations (Rg) revealed the domain indicating the conformations for herbicide resistant. Based on the enlarging-contracting mechanism of active site entrance, we designed new herbicides with substitution at the heterocyclic moiety of a SU herbicide for the complementary binding to the changed active site entrances of mutants, and designed new herbicides. We confirmed that our screened new herbicides bonded to both AHAS wild type and mutants with higher affinity, showing more stable binding conformation than the existing herbicides.

• 한국육종학회지
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• 제40권2호
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• pp.128-135
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• 2008

Herbicide resistance is the most common trait being tested and thus herbicide?resistant genetically modified plants are now the most widely cultivated worldwide. Here we developed herbicide?resistant transgenic Agrostis mongolica Roshev. by employing an efficient Agrobacterium?mediated transformation procedure with 25.2% of transformation efficiency. The identification and employment of regenerable and reproducible type of callus was one of the most critical factors to ensure success in this study. PCR analysis confirmed that the bar transgene was integrated into the genome of transgenic plants. The expression of 35S?bar gene was confirmed by Northern blot analysis. The transgenic plants showed complete resistance to herbicide, indicating that the bar gene is functional in transgenic plants.

• Weed & Turfgrass Science
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• 제3권2호
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• pp.110-113
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• 2014

The continuous use of acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibitors has led to the selection of herbicide resistant barnyardgrass populations in direct-seeded rice fields of Korea. This study was conducted to identify herbicide resistant barnyardgrass biotypes and to determine the cross- and multiple-resistance of them. 25% of the population collected from Taeahn was partially resistant to ACCase inhibitors and 22% collected from Kimjae were partially resistant to ALS inhibitors. However, 8.2% of the population from both sites was resistant to ALS and ACCase inhibitors. Resistance to sulfonylurea herbicide, flazasulfuron was identified from two barnyardgrass accessions collected from both Taeahn and Kimjae. One barnyardgrass accession from both sites was resistant to ACCase inhibitor, sethoxydim. The cross-resistance to ALS inhibitors was identified at one barnyardgrass accession from Taeahn and at two accessions from Kimjae. Further, crossresistance to ACCase inhibitors was also identified at barnyardgrass accessions from Taeahn and Kimjae. Multiple-resistance to flazasulfuron and sethoxydim was determined at four barnyardgrass accessions from Taeahn and at six accessions from Kimjae. Therefore, the herbicide mixture and sequences within a growing season or the herbicide rotation with different modes of actions across growing seasons are recommended to control herbicide-resistant barnyardgrass in infested fields.

• 한국잡초학회지
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• 제4권1호
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• pp.96-106
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• 1984

Changes in weed floras and development of plant resistance to herbicides seemed to be closely related with increased and repeated use of herbicides. Herbicide use increased from 5% of the total consumption of pesticide in 1950 to 45% in 1976 in world basis. About 200 herbicides have been introduced to agriculture so as to control about 206 weed species which have been recorded important to human beings. In Korea, there was about 351 times in increased use of herbicides from 1966 to 1982. Interspecific selection by herbicide is mainly responsible for changes in weed floras and resulted in varying tolerance or susceptibility to herbicides, together with the changes of agricultural practices. The present trend toward continuous cereal cultivation throughout world will lead to type of changes in weed floras favorable to therophyte which can survive under unfavorable conditions as seeds rather than the types of geophyte which can survive unfavorable seasons as buds placed below soil surface. However, geophyte such as Sagitaria pygmaea, and Scirpus jurtcoides, and Cyperus rotundus and Cynodon dactylon in temperate warm climate become severe paddy weeds, presumably because of the removal of annual weeds by herbicides. Since differential tolerance to 2,4-D was firstly reported in Agrostis stolofera, about 30 species of weeds in 18 genera are presently known to have developed resistance to triazine herbicides. Resistance of weed biotypes to triazine herbicide is not mainly due to limited absorption and translocation or to the difference in metabolism, but is the result of biochemical changes at the site of metabolic activity, such as a loss of herbicide affinity for triazine binding site in the photosystem II complex of the chloroplast membrane. Genetical study showed that plastid resistance to triazine was wholly inherited through cytoplasmic DNA in the case of Brassica campestris. Plant tissue culture method can be utilized as an alternate mean of herbicide screening and development of resistance variants to herbicides as suggested by Chaleff and Parsons. In this purpose, one should be certain that the primary target process is operational in cell culture. Further, there are a variety of obstacles in doing this type of research, particularly development of resistance source and it's regeneration because cultured cells and whole plants represent different developmental state.

• Weed & Turfgrass Science
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• 제7권2호
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• pp.166-169
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• 2018

경남지역 제초제 저항성 피의 발생현황과 저항성 정도를 알아보기 위하여 벼 재배 논에서 100개체의 피 종자를 수집하여 ACCase 저해제인 cyhalofop-butyl에 대한 약량반응 실험을 수행한 결과, 수집한 피의 7%가 저항성으로 조사되었다. 선발된 감수성 5개체의 $GR_{50}$값은 평균 $147g\;a.i.\;ha^{-1}$로 나타났고, 함양 지역의 저항성 개체의 $GR_{50}$값은 $738g\;a.i.\;ha^{-1}$ 로 R/S (ratio of resistance to sensitivity)값은 5.01배로 나타났다. 현재 경남지역에서의 저항성 피의 발생 수준은 낮은 것으로 나타났지만, 저항성 피의 확산을 지연시키거나 막기 위해서는 주기적인 저항성 피의 모니터링과 체계적인 저항성 잡초 관리방안을 마련하여 수행할 필요가 있다.

• Journal of Microbiology and Biotechnology
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• 제11권1호
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• pp.7-12
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• 2001

Three Pseudomonas strains (Bk8, Bk9, Bk10) selected from soil for their ability to degrade herbicide diuron were tested for their heavy metal resistance. The growth of these catabolic strains on a minimal medium with various concentrations of $Cd^{2+},\;Zn^{2+},\;Ni^{2+}$, and $Hg^{2+}$ revealed a minimal effect on the carbon source for the inhibitory effect of the metals. One of these strains, namely, Bk8, exhibited a high resistance to the heavy metals as compared to the two other strains. This strain harbors plasmid pBk8 (110 kb) and contains at least fur determinants encoding heavy metal resistance. Nickel and zinc resistance are encoded by genes located on the chromosome, while cadmium and mercury resistance are on plasmid pBk8. Accordingly, the characteristics of strain Bk8 suggest that it would be useful in the bioremediation of aromatic compounds in the presence of toxic heavy metals as co-contaminants.

• The Plant Pathology Journal
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• 제17권1호
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• pp.1-8
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• 2001

The technique of plant transformation has started to show off its great power in the area of plant breeding by commercially successful introduction of transgenic varieties such as herbicide tolerant soybean and insect resistant corn in USA with an unimaginable speed. However, in contrast with the great success in the commercialization of herbicide tolerance and insect resistance, the transformation works on disease resistance has not yet reached the stage of full commercialization. This review surveys the current status of molecular breeding for plant disease resistance and their limits and problems. Some novel ideas and approaches in molecular breeding for disease resistance are introduced.

• Weed & Turfgrass Science
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• 제5권3호
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• pp.105-110
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• 2016

세계 잡초연구자들이 세계잡초학회에서 발표한 최근 연구동향을 파악하여 이를 토대로 향후 잡초연구 발전방향과 전망을 제시하고자 하였다. 제 7차 세계잡초학회는 우리나라를 포함한 59개국 520여명이 참석하였으며, 9개 분야 625편이 발표되었다. 주요 연구분야로는 제초제 저항성잡초, 잡초생태, 농경지 및 비농경지의 잡초관리, 제초제 살포기술, 비화학적 잡초방제 등이었다. 이중 제초제 저항성잡초 연구분야는 전체 30%를 점유하여 향후에도 이들 연구가 지속될 것으로 판단된다. 특히 설포닐우레아계 보다는 비선택성 제초제인 glyphosate, glufosinate-ammonium 저항성 잡초에 대한 발표가 많았다. 신규 제초제 개발은 synthetic auxin 작용기작의 제초제인 arylex, HPPD 저해제로 개발 중인 3가지 물질을 safener와의 합제 연구 등이 있었다. 그리고 세계 주곡작물인 옥수수, 밀, 벼 재배지에서 발생되는 제초제 저항성잡초에 대한 연구가 집중되었다. 특히 잡초의 non-target site에 대한 저항성 연구가 집중적이었다. 또한 우리나라에는 없는 기생잡초에 대한 연구 폭이 넓어지고 있으며, 예년에는 취급하지 않았던 비화학적 잡초방제 부문도 많았다. 향후에는 제초제 저항성 메카니즘 구명, 기생잡초 연구, 제초제 살포기술, 비화학적 잡초방제 등의 연구가 폭넓게 진행될 것으로 전망되었다.