• 한국작물학회지
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• 제49권5호
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• pp.434-439
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• 2004

Medicago truncatula is a model plant for molecular genetic studies of legumes and plant-microbe interactions. To accelerate finding of genes that play roles in the early stages of nodulation and stress responses, a trans-genic plant was developed that contains a promoter­reporter fusion. The promoter of rip], a Rhizobium-induced peroxidase gene, was fused to the coding region of $\beta-glucuronidase (GUS)$ gene and inserted into a modified plant transformation vector, pSLJ525YN, in which the bar gene was preserved from the original plasmid but the neomycin phosphotransferase gene was replaced by a polylinker. Transformation of M. truncatula was carried out by vacuum infiltration of young seedlings with Agrobacterium. Despite low survival rates of infiltrated seedlings, three independent transformants were obtained from repeated experiments. Southern blot analyses revealed that 7 of 8 transgenic plants of the T 1 generation contained the bar gene whereas 6 $T_1$ plants contained the GUS gene. These results indicate that vacuum infiltration is an effective method for transformation of M. truncatula. The progeny seeds of the transgenic plants will be useful for mutagenesis and identification of genes that are placed upstream and may influence the expression of rip] in cellular signaling processes including nodulation.

• The Plant Pathology Journal
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• 제17권2호
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• pp.67-70
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• 2001

Medicago truncatula is a diploid legume plant related to the forage crop alfalfa. Recently, it has been chosen as a model species for genomic studies due to its small genome, self-fertility, short generation time, and high transformation efficiency. M. truncatula engages in symbiosis with nitrogen-fixing soil bacterium Rhizobium meliloti. M. truncatula mutants that are defective in nodulation and developmental processes have been generated. Some of these mutants exhibited altered phenotypes in symbiotic responses such as root hair deformation, expression of nodulin genes, and calcium spiking. Thus, the genes controlling these traits are likely to encode functions that are required for Nod-factor signal transduction pathways. To facilitate genome analysis and map-based cloning of symbiotic genes, a bacterial artificial chromosome library was constructed. An efficient polymerase chain reaction-based screening of the library was devised to fasten physical mapping of specific genomic regions. As a genomics approach, comparative mapping revealed high levels of macro- and microsynteny between M. truncatula and other legume genomes. Expressed sequence tags and microarray profiles reflecting the genetic and biochemical events associated with the development and environmental interactions of M. truncatula are assembled in the databases. Together, these genomics programs will help enrich our understanding of the legume biology.

• 한국초지조사료학회지
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• 제24권1호
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• pp.21-24
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• 2004

알팔파(Medicago sativa L.)의 치사온도를 결정하기 위하여, "Vernal" 품종을 시험재료로 하여 종자를 Petri dish에서 발아시켜 작은 화분에 10 개체씩 이식, 생장실에서 4주간 재배하였다. 45, 50 및 $55^{\circ}C$에서 처리한 경우에는 60분간 처리했을 때에도 거의 식물체 손상이 없었다. 6$0^{\circ}C$에서 60분간 처리했을 때에는 잎이 약간 시든 듯한 현상이 있었으나 식물체의 손상은 거의 없는 상태였으며, $65^{\circ}C$에서 60분간 처리했을 때에도 $60^{\circ}C$에서 처리한 결과와 마찬가지로 심한 손상은 받지 않았다. $70^{\circ}C$에서 60분간 처리했을 때에 알팔파는 일부에서 잎만 조금 마른 현상이 나타났으나, 치사온도에는 도달하지 않았다. $80^{\circ}C$에서 처리한 결과에서는 처리 후 1일 이내에 60분 처리에서 거의 죽어가는 현상이 나타났다. 처리 후 7일에는 50분 처리에서 모두 죽었으며, 45분 이하의 처리에서는 새로운 shoot가 재생됨을 확인하였다. 결론적으로 알팔파의 치사온도는 $80^{\circ}C$에서 50분 처리하는 것으로 결정되었다.것으로 결정되었다.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.57.1-57
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• 2000

No Abstract, See Full Text

• 한국초지조사료학회지
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• 제4권2호
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• pp.81-88
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• 1983

• Journal of Plant Biotechnology
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• 제6권2호
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• pp.87-90
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• 2004

An efficient plant regeneration system in alfalfa (Medicago sativa L.) through somatic embryogenesis was established. Embryogenic callus was obtained by culture of hypocotyl segments on MS medium with 0.02mg $L^{-1}$ IAA and 1.0mg $L^{-1}$ zeatin after 45 days of culture. Embryogenic calli were converted to the somatic embryos when transferred to either MS medium without plant growth regulators (PGRs) or MS medium containing various cytokinin (BA, kinetin and zeatin). Most of the somatic embryos were developed into plantlets on MS medium supplemented with 0.1 mg $L^{-1}$ kinetin. Also, secondary embryos appeared on the surface of primary embryo but they showed abnormal growth. Regenerated plantlets were transplanted to pots containing vermiculite and perlite for further analysis.

• Journal of Plant Biology
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• 제37권3호
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• pp.357-363
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• 1994

An expreiment with non-nodulating alfalfa (Medicago sativa L.) plants was designed to investigate the changes in protein contents and the activities of proteolytic enzymes during a regrowth period of 24 d. Shoot removal caused a depression of root growth and significantly reduced protein contents in roots. An initial decline of root proteins for the first 10 d was followed by a rapid recovery from d 11 to 24. The major increase of regrowing shoot weight occurred also from d 11. The activities of aminopeptidase and endoprotease slightly decreased in regrowing leaves, while protein contents remains stable after shoot removal. Roots exhibited source behaviour with a rapid increase of endoprotease activities for the first 10 d of regrowth; about a 370% increase over the initial level was observed. Increase in endoprotease activity in roots coincided with the time of protein remobilization after shoot removal, indicating the important role of endoproteases in protein degradation.

• 한국초지조사료학회지
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• 제4권2호
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• pp.115-121
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• 1983

• 한국토양비료학회지
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• 제8권1호
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• pp.37-43
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• 1975

현지기후풍토(現地氣候風土)에 적합할 것으로 생각되는 7품종(品種) Alfalfa (Washo, Ranger, Lahontan, Narragensett, Atlantic, Vernal, Moapa 69)의 건물생산량과 생육(生育)에 미치는 근류균접종효과에 관한 실험(實驗)을 비교적 척박한 토양(土壤)에 종자(種子) 30l에 근류균(根瘤菌) 6oz 비율로 도말하여 파종(播種) 1973-74년 2년간(年間) 실시하였다. 1. 공시된 품종(品種)에서 근류균(根瘤菌)을 접종(接種)한 구(區)가 접종(接種)하지 않은 구(區)에 비하여 초장(草長) 및 건물량(乾物量)에 있어서 현저한 증가를 보였다. 2. 1973년(年) Pot 시험에서 접종구(接種區)의 건물생산량은 Moapa 69> Vernal> Lahontan> Washoe> Atlantic> Narragensett> Ranger 의 순(順)이었다. 3. 다음해 포장(圃場)에 이식(移植)한 후에는 접종(接種)과 무접종간(無接種間)의 건물생산량에 차이가 없었다. 총건물(總乾物) 생산량은 Washoe> Lahontan> Moapa 69> Ranger> Narrangensett> Vernal> Atlantic의 순(順)이었다.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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• pp.256-263
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• 2006

In the model legume Medicago truncatula, two mutants, sickle and sunn, exhibit morphologically and genetically distinct hypernodulation phenotypes. However, efforts to isolate the single recessive and single semidominant genes for sickle and sunn, respectively, by map-based cloning have so far been unsuccessful, partly due to the absence of clones that enable walks from linked marker positions. To help resolve these difficulties, a new bacterial artificial chromosome (BAC) library was constructed using BamHI-digested genomic fragments. A total of 23,808 clones were collected from ligation mixtures prepared with double-size-selected high-molecular-weight DNA. The average insert size was 116 kb based on an analysis of 88 randomly selected clones using NotI digestion and pulsed-field gel electrophoresis. About 18.5% of the library clones lacked inserts. The frequency of the BAC clones carrying chloroplast or mitochondrial DNA was 0.98% and 0.03%, respectively. The library represented approximately 4.9 haploid M. truncatula genomes. Hybridization of the BAC clone filters with a $C_{0}t-l$ DNA probe revealed that approximately 37% of the clones likely carried repetitive sequence-enriched DNA. An ordered array of pooled BAC DNA was screened by polymerase chain reactions using 13 sequence-characterized molecular markers that belonged to the eight linkage groups. Except for two markers, one to five positive BAC clones were obtained per marker. Accordingly, the sickle- and sunn-linked BAC clones identified herein will be useful for the isolation of these biotechnologically important genes. The new library will also provide clones that fill the gaps between preexisting BAC contigs, facilitating the physical mapping and genome sequencing of M. truncatula.