• 식물분류학회지
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• 제46권2호
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• pp.129-148
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• 2016

Plant species on oceanic islands comprise nearly 25% of described vascular plants on only 5% of the Earth's land surface yet are among the most rare and endangered plants. Conservation of plant biodiversity on islands poses particular challenges because many species occur in a few and/or small populations, and their habitats on islands are often disturbed by the activity of humans or by natural processes such as landslides and volcanoes. In addition to described species, evidence is accumulating that there are likely significant numbers of "cryptic" species in oceanic archipelagos. Plant systematists, in collaboration with others in the botanical disciplines, are critical to the discovery of the subtle diversity in oceanic island floras. Molecular data will play an ever increasing role in revealing variation in island lineages. However, the input from plant systematists and other organismal biologists will continue to be important in calling attention to morphological and ecological variation in natural populations and in the discovery of "new" populations that can inform sampling for molecular analyses. Conversely, organismal biologists can provide basic information necessary for understanding the biology of the molecular variants, including diagnostic morphological characters, reproductive biology, habitat, etc. Such basic information is important when describing new species and arguing for their protection. Hybridization presents one of the most challenging problems in the conservation of insular plant diversity, with the process having the potential to decrease diversity in several ways including the merging of species into hybrid swarms or conversely hybridization may generate stable novel recombinants that merit recognition as new species. These processes are often operative in recent radiations in which intrinsic barriers to gene flow have not evolved. The knowledge and continued monitoring of plant populations in the dynamic landscapes on oceanic islands are critical to the preservation of their plant diversity.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.85.1-85
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• 2003

In most ascomycetes, a single mating type locus, MAT, with two alternate forms (MAT1-1 and MAT1-2) called idiomorphs, controls mating ability. In heterothallic ascomycetes these alternate idiomorphs reside in different nuclei. In contrast, most homothallic ascomycetes carry both MAT1-1 and MAT1-2 in a single nucleus, usually closely linked. An example of the latter is Gibberella zeae, a producer of mycotoxins such as trichothecene and zearalenone that threaten human and animal health. We asked if G. zeae could be made strictly heterothallic by manipulation of MAT. Targeted gene replacement was used to differentially delete MAT1-1 or MAT1-2 from a wild type haploid MAT1-1 MAT1-2 strain, resulting in MAT1-1；mat1-2, mat1-1；MAT1-2 strains that were self-sterile, yet able to cross to wild type testers and more importantly, to each other. These results indicated that differential deletion of MAT idiomorphs eliminates selfing ability of G. zeae, but the ability to outcross is retained. To our knowledge, this is the first report of complete conversion of fungal reproductive strategy from homothallic to heterothallic by targeted manipulation of MAT. Practically, this approach opens the door to simple and efficient procedures for obtaining sexual recombinants of G. zeae that will be useful for genetic analyses of mycotoxin production and other traits, such as ability to cause disease.

• 한국식물병리학회지
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• 제10권3호
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• pp.228-234
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• 1994

Genomic RNA was extracted from Cy strain of odontoglossum ringspot tobamovirus (ORSV-Cy) isolated from infected leaves of tobacco cv. Samsun. Size of the genomic RNA was about 6.6 kb in length. The genomic RNA was fractionated using Sephadex G-50 column chromatography into 2 fractions. They were polyadenylated at their 3'-end using E. coli poly(A) polymerase. Polyadenylated viral RNA was recovered by oligo (dT) primer adapter containing NotI restriction site and Moloney murine leukemia virus SuperScript reverse transcriptase (RNase H-). Second-strand cDNA was synthesized by using E. coli DNA ligase, E. coli DNA polymerase I and E. coli RNase H. Recombinant plasmids containing cDNAs for ORSV-Cy RNA ranged from about 800 bp to 3,000 bp. Among the selected 238 recombinants, pORCY-124 clone was the largest one covering 3'-terminal half of the viral RNA. This clone contained two restriction sites for EcoRI and XbaI and one site for AccI, AvaI, BglII, BstXI, HindIII, PstI, and TthIII 1. respectively. The clone contained partial viral replicase, a full-length movement protein and a complete coat protein genes followed by a 3' untranslated region of 414 nucleotides based on restriction mapping and nucleotide sequencing analyses. Clones pORCY-028, -068, -072, -187 and -224 were overlapped with the pORCY-124. Clones pORCY-014 and -095 covered 5' half upstream from the middle region of the viral RNA, which was estimated based on restriction mapping and partial sequence analysis. Constructed cDNA library covered more than 90% of the viral genome.

• The Plant Pathology Journal
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• 제25권4호
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• pp.417-421
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• 2009

The analysis of the full length genome of Korean isolates of Pepper mottle virus (PepMoV) in previous study showed molecular variations and are found to be related to symptom variation and pathogenicity (Kim et al., 2009, Virus Res. 144:83-88). To fully understand the molecular variation of PepMoV in Korea, we further assessed the role of RNA recombination to biological variation and evolution of PepMoV. Full-length genome of a total of 17 Korean-PepMoV and 2 American (CA and FL) isolates were examined for possible detection of genetic recombination using different recombination detections programs and detected 5 and 8 tentative recombination events using RDP3 and Splits Tree4 programs, respectively. Interestingly, tentative recombinants detected such as isolates 57, 134 and 217 were previously identified as severe isolates and 205135 and 205136 as differentiating isolates (Kim et al., 2009, Virus Res. 144:83-88). In addition, recombination was frequently detected in the Vb isolate, the first PepMoV isolate reported in Korea, suggesting significant involvement in the evolution of PepMoV in Korea. These initial results of our recombination analyses among PepMoV isolates in Korea may serve as clues to further investigate the biological variations and evolution of PepMoV brought about by recombination.

• Journal of Microbiology and Biotechnology
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• 제19권8호
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• pp.823-828
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• 2009

An endo-${\beta}-1$,4-xylanase (${\beta}$-xylanase) from Trichoderma harzianum C4 was purified without cellulase activity by sequential chromatographies. The specific activity of the purified enzyme preparation was 430 units/mg protein on D-xylan. The complementary DNA (cDNA) encoding ${\beta}$-xylanase (xynII) was amplified by PCR and isolated from cDNA PCR libraries constructed from T. harzianum C4. The nucleotide sequence of the cDNA fragment contained an open reading frame of 663 bp that encodes 221 amino acids, of which the mature protein is homologous to several ${\beta}$-xylanases II. An intron of 63 bp was identified in the genomic DNA sequence of xynII. This gene was expressed in Saccharomyces cerevisiae strains under the control of adh1 (alcohol dehydrogenase I) and pgk1 (phosphoglycerate kinase I) promoters in 2 ${\mu}$-based plasmids, which could render recombinants able to secrete ${\beta}$-xylanase into the media.

• 원예과학기술지
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• 제33권4호
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• pp.550-558
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• 2015

To analyze the linkage relationships among molecular markers recently reported to be linked to onion (Allium cepa L.) Ms, a restorer-of-fertility locus, in onion (Allium cepa L.), three single nucleotide polymorphism markers were converted into cleaved amplified polymorphic sequence (CAPS) markers based on onion transcriptome sequences and the rice genome database. Analysis of the recombinants selected from 4,273 segregating plants using CAPS and other linked markers demonstrated the jnurf13 and jnurf610 markers to perfectly co-segregate with the Ms locus. In contrast to jnurf13, the jnurf610 marker was not in perfect linkage disequilibrium with the Ms locus in diverse breeding lines. Thus, the jnurf13 marker and the marker for identification of cytoplasm types were utilized to enhance the efficiency of onion breeding through four applications. First, 89 maintainer lines containing the normal cytoplasm and homozygous recessive Ms genotypes were successfully identified from 100 breeding lines. Second, these two molecular markers were used to analyze the main sources of male-fertile contaminants frequently found in the male-sterile parental lines during F1 hybrid seed production. The majority of the contaminants contained heterozygous Ms genotypes, indicating that pollen grains harboring the dominant Ms genotype may have been introduced during propagation of the maintainer lines. Therefore, the genetic purity of the two maintainer lines was analyzed in the third application, and the results showed that both maintainer lines contained 13-21% off-types. Finally, the two markers were used to increase the seed yield potentials of two open-pollinated varieties containing sterile cytoplasms by removing the plants harboring homozygous recessive and heterozygous Ms genotypes.

• 한국미생물·생명공학회지
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• 제14권3호
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• pp.265-270
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• 1986

L. casei세포의 유전연구를 위한 도구로서 세포융합 기술을 연구하였으며 융합세포(recombinant)를 선발하고 확인하기 위한 유전자 선발표지 인자로서 항생제 저항성이 이용되었고, 항생제 저항성 돌연변이 균주는 nitrosoguanidine을 처리하여 분리하였다. 선발 배지에서 항생제의 적절한 최종 농도는 streptomycin 25 $\mu\textrm{g}$/$m{\ell}$, hostacillin 0.5 I. U./$m{\ell}$, lincomycin 0.5$\mu\textrm{g}$/$m{\ell}$ 그리고 methicillin 5 $\mu\textrm{g}$/$m{\ell}$로 확인되었다. L. casei균주에서 높은 세포융합은 PEG 분자량 4,000에서 40%농도, 중성 부근의 pH, 3$0^{\circ}C$에서 약 1분간 처리하였을 때 얻어 졌다. 항생제 저항성의 자연돌연변이주의 출현빈도는 세포융합 출현빈도 보다 $10^2$-$10^3$ 정도 낮은 수준으로 나타났다. 세포융합 빈도는 모균에 대해 약 $10^{-4}$ 비율로 나타났다.

• The Plant Pathology Journal
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• 제23권4호
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• pp.251-259
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• 2007

Two isolates of Cucumber mosaic virus (CMV) originated from lily plants, named Ly2-CMV and Ly8-CMV, were compared with their pathological features in several host plants. Ly2-CMV and Ly8-CMV could induce systemic mosaic symptom in Nicotiana benthamiana, but Ly2-CMV could not systemically infect tomato and cucumber plants that have been used for CMV-propagative hosts. While Fny-CMV used as a control infected systemically the same host plants, producing typical CMV symptoms. Ly8-CMV could infect systemically two species of tobacco (N. tabacum cv. Xanthi-nc and N. glutinosa) and zucchini squash (Curcubita pepo), but Ly2 failed systemic infection on these plants. As resulted from tissue-print immunoblot assay, different kinetics of systemic movement between Ly2-CMV and Ly8-CMV were crucial for systemic infection in tobacco (cv. Xanthi-nc). Sequence analysis of full-length genome of two lily isolates showed Ly2 and Ly8 belonged to subgroup IA of CMV. The lily isolates shared overall 98 % sequence identity in their genomes. Coat protein, 3a protein, and 2b protein involved in virus movement was highly conserved in genomes of the isolates Ly2 and Ly8. Although there is the low frequency of recombinants and reassortants in natural CMV population, phylogenetic analysis of each viral protein among a number of CMV isolates suggested that genetic variation in a defined population of CMV lily isolates was stochastically produced.

• 생명과학회지
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• 제14권2호
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• pp.339-344
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• 2004

콩에서 경장과 연관된 DNA 표지인자를 개발하여 품종육성에 활용함으로서 육종효율 증진에 기여하고자 수행하였다. 본 시험은 육성된 큰올콩과 신팔달콩의 RIL 계통 및 SSR marker를 이용하여 유전자지도를 작성하고, 이를 바탕으로 경장과 관련된 양적형질 유전자좌(QTt)를 탐색하였다. 시험재료로 이용된 큰올콩과 신팔달콩은 경장이 각각 30.57 cm와 49.75 cm로 매우 큰 차이를 보였다. 경장과 연관된 QTL은 개별마커들과의 분산분석 결과, 연관군 F, J, N 및 O에서 전체변이의 37.83%를 설명할 수 있는 4개의 QTL을 탐색하였다. 특히, 연관군 J와 O에서 각각 14.25%와 10.68%를 설명할 수 있는 주요 QTL을 확인하였다. 따라서 경장 관련 QTL중 연관군 J와 O에서 확인된 주요 QTL은 품종 육성과정에서 경장 관련 선발 마커로서 활용가치가 높은 것으로 판단된다.

• 미생물학회지
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• 제25권3호
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• pp.198-204
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• 1987

P. pulida KU218R-3와 P. Putida KU42엠 원형질체 혼합액에 PEG 6000을 처리하여 biparental형과 recombinant형의 융합체를 얻었다. Pseudomonasd의 원형질체가 융합하는 형태는 TEM으로 관찰하였고, 원형질 융합체의 선별은 항생제 내성을 유전적 지표로 하여 간접적인 방법으로 선별하였다. Pseudomonas의 원형질체 융합에는 40% (w / v) PEG 6000을 상온에서 10분간 처리하는 것이 가장 효과적이었으나 PEG를 처리하지 않은 실험구에서도 융합체가 4%의 빈도로 생성되므로 PEG의 효과는 절대적인 것이 아니었다. 생성된 융합체의 대부분은 biparental clone이었고 (10.4%), recombinant clone의 생성빈도 는 너무 낮았디 (0.12%). 또한 biparental clone의 대부분은 further propagation 증에 모균주의 형태로 분리되었고, 이 과정 에서 late recombinant플 생성하였다. biparental clone에 t얀해 rE'combinant clonE은 여러 셔1대 후에도 안정하였다.