• The Plant Pathology Journal
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• v.21 no.1
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• pp.55-58
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• 2005

In order to diagnose and differentiate jujube witches' broom (JWB) phytoplasma rapidly, oligonucleotide primer pair, 16Sr(V) F/R, for polymerase chain reactions (PCRs) was designed on the basis of 16S rRNA sequences of JWB phytoplasma. The PCR employing phytoplasma universal primer pair P1/P7 consistently amplified DNA in all tested phytoplasma isolates. But no phytoplasma DNA was detected from healthy jujube seedlings. The nested PCR, the primer pair 16S(V) F/R, about 460 bp fragment, amplified DNA in all tested JWB and related phytoplasmas including ligustrum witches' broom phytoplasma of the 16S rRNA group V, but no DNA amplification was detected from other phytoplasma strains such as groups 16SrI (Aster yellows) and 16SrXII (Stolbur group) in which mulberry dwarf phytoplasma and chrysanthemum witches' broom phytoplasma belong to, respectively. The same results were obtained from both Korean and Chinese isolates of JWB phytoplasma. Nested-PCR using phytoplasma universal primer pair P1/P7 and 16SrV group-specific primer pair 16S(V) F/R could detect group V phytoplasmas rapidly and easily, in particular JWB phytoplasma.

• Molecules and Cells
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• v.21 no.3
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• pp.418-427
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• 2006

Ionotropic glutamate receptors (iGluRs) are ligand-gated nonselective cation channels that mediate fast excitatory neurotransmission. Although homologues of the iGluRs have been identified in higher plants, their roles are largely unknown. In this work we isolated a full-length cDNA clone (RsGluR) encoding a putative glutamate receptor from small radish. An RsGluR:mGFP fusion protein was localized to the plasma membrane. In Arabidopsis thaliana overexpressing the fulllength cDNA, glutamate treatment triggered greater $Ca^{2+}$ influx in the root cells of transgenic seedlings than in those of the wild type. Transgenic plants exhibited multiple morphological changes such as necrosis at their tips and the margins of developing leaves, dwarf stature with multiple secondary inflorescences, and retarded growth, as previously observed in transgenic Arabidopsis overexpressing AtGluR3.2 [Kim et al. (2001)]. Microarray analysis showed that jasmonic acid (JA)-responsive genes including defensins and JA-biosynthetic genes were up-regulated. RsGluR overexpression also inhibited growth of a necrotic fungal pathogen Botrytis cinerea possibly due to up-regulation of the defensins. Based on these results, we suggest that RsGluR is a glutamate-gated $Ca^{2+}$ channel located in the plasma membrane of higher plants and plays a direct or indirect role in defense against pathogen infection by triggering JA biosynthesis.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.143.1-143.1
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• 2011

Deep Ca,b,y images obtained from the CTIO 4m Blaco telescope are used to investigate the multiple stellar populations of red giant branch (RGB) and sub-giant branch (SGB) in Galactic globular clusters NGC 6656 and NGC 6723. For NGC 6656, confirming the result of Lee et al. (2009), we find two discrete populations of the RGB stars of which mean color separation is about 0.2 mag in hk[=(Ca-b)-(b-y)] index. Furthermore, we also find the bimodel distribution of the SGB stars in (hk, y) color-magnitude diagram. A new finding is that the (hk, y) color-magnitude diagram of NGC 6723 shows two distinct RGB stars with different calcium abundances of which mean color separation is about 0.12 mag in hk index. This multiple stellar feature has not been observed in previous observation, suggesting that NGC 6723 may also be a possible relic of dwarf galaxies that merged into the Milky Way in the past. Thus our result adds further constraints to the merging scenario of the Galaxy formation. Unfortunately, the split of SGB stars in NGC 6723 is not obvious. We will present some statistical results to compare properties of two populations in two clusters.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.30.2-30.2
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• 2009

There is a growing body of evidence for the presence of multiple stellar populations in some globular clusters, including NGC 1851. For most of these peculiar globular clusters, however, the evidence for the multiple red giant-branches (RGBs) having different heavy elemental abundances as observed in $\omega$ Centauri is hitherto lacking, although spreads in some lighter elements are reported. It is therefore not clear whether they also share the suggested dwarf galaxy origin of $\omega$ Cen or not. Here we show from the CTIO 4m UVI photometry of the globular cluster NGC 1851 that its RGB is clearly split into two in the U - I color. The two distinct RGB populations are also clearly separated in the abundance of heavy elements as traced by Calcium, suggesting that the type II supernovae enrichment is also responsible, in addition to the pollutions of lighter elements by intermediate mass asymptotic giant branch stars or fast-rotating massive stars. The RGB split, however, is not shown in the V - I color, as indicated by previous observations. Our stellar population models show that this and the presence of bimodal horizontal-branch distribution in NGC 1851 can be naturally reproduced if the metal-rich second generation stars are also enhanced in helium.

• Journal of The Korean Astronomical Society
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• v.51 no.6
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• pp.197-206
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• 2018

We present the analysis of KMT-2016-BLG-0212, a low flux-variation ($I_{flux-var}{\sim}20mag$) microlensing event, which is in a high-cadence (${\Gamma}=4hr^{-1}$) field of the three-telescope Korea Microlensing Telescope Network (KMTNet) survey. The event shows a short anomaly that is incompletely covered due to the brief visibility intervals that characterize the early microlensing season when the anomaly occurred. We show that the data are consistent with two classes of solutions, characterized respectively by low-mass brown-dwarf (q = 0.037) and sub-Neptune (q < $10^{-4}$) companions. Future high-resolution imaging should easily distinguish between these solutions.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.45.1-45.1
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• 2021

Horizon Run 5 (HR5) is a cosmological hydrodynamical simulation which captures the properties of the Universe on aGpc scale while achieving a resolution of 1kpc. This enormous dynamic range allows us to simultaneously capture the physics of the cosmic web on very large scales and account for the formation and evolution of dwarf galaxies on much smaller scales. On the back of a remarkable achievement of this, we have finished to run follow-up simulations which have 2 times larger volume than before and are expected to complementary to some limitations of previous HR simulations both for the study on the large scale features and the expansion history in a distant Universe. For these simulations, we consider the sub-grid physics of radiative heating/cooling, reionization, star formation, SN/AGN feedbacks, chemical evolution and the growth of super-massive blackholes. In order to do this project, we implemented a hybrid MPI-OpenMP version of the RAMSES code, 'RAMSES-OMP', which is specifically designed for modern many-core many thread parallel systems. These simulation successfully reproduce various observation result and provide a large amount of statistical samples of Lyman-alpha emitters and protoclusters which are important to understand the formation and expansion history of early universe. These are invaluable assets for the interpretation of current ΛCDM cosmology and current/upcoming deep surveys of the Universe, such as the world largest narrow band imaging survey, ODIN (One-hundred-square-degree Dark energy camera Imaging in Narrow band).

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.36.1-36.1
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• 2020

The progenitor of Type Ia supernovae (SNe Ia) is mainly believed to be a carbon/oxygen white dwarf (WD) with non-degenerate (single degenerate) or another WD companion (double degenerate). However, there is little observational evidence of their progenitor system. Recent studies suggest that shock-breakout cooling emission after the explosion can constrain the size of the progenitor system. To do so, we obtained a optical/Near-IR light curve of SN 2019ein, a normal but slightly sub-luminous type Ia supernova, from the very early phase using our high-cadence observation of Intensive Monitoring Survey of Nearby Galaxies (IMSNG). Assuming the expanding fireball model, the simple power-law fitting of the early part of the light curve gives power indices of 1.91 (B) and 2.09 (R) implying radioactive decay of 56Ni is the dominant energy source. By comparison with the expected light curve of the cooling emission, the early observation provides us an upper limit of the companion size of R∗≤1R⊙. This result suggests that we can exclude a large companion such as red giants, which is consistent with the previous study.

• Research in Plant Disease
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• v.18 no.3
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• pp.245-249
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• 2012

The small brown planthopper (Laodelphax striatellus) is one of the most important rice pests in Republic of Korea because it damages rice plants not only by sap-sucking but also by transmitting Rice stripe virus (RSV). Outbreaks of RSV are closely related to outbreaks of the small brown planthopper (SBPH). Therefore, it is very important to control SBPH for the management of RSV. Mass-migrating SBPH collected by aerial net traps in June 2011 at Taeanup, Geunheungmyon and Gonammyon in Taeangun were examined for virus carrier status and effects of the pesticide, 'Myungtaja', on the control of RSV. Among 1,217 SBPH trapped, about 7.7% were detected as RSV positive and 4.4% were positive for Rice black streak dwarf virus (RBSDV) by RT-PCR. After the mass migration, pesticide 'Myungtaja' was sprayed once or twice on rice fields and compared to untreated fields. The incidence of RSV was not affected by the frequency of spraying 'Myungtaja' but was influenced by the time of pesticide treatment. Myungtaja' treatment within 5-7 days after mass migration resulted in the most efficient RSV control, resulting in RSV incidence decreased by 87.6% compared to the control. Therefore, we conclude that pesticide spraying for RSV control was most effective when it was done within 5-7 days after mass migration.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.159-168
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• 1996

The major morphological characteristics of 97 lines selected from 1,510 local collection lines of Paeonia spp. were studied and classified into some groups according to their Q correlation. The Coefficient of Variation of 8 characteristics in 97 lines varied greatly with the range from 21.3% to 127.1%. The 22 lines with useful morphological characteristics selected from 97 lines had 2n=10 chromosomes, in which there were no difference among the number of chromosomes of 22 lines. The 97 lines were classified into 14 groups based upon the results of Q correlation analysis obtained from data with 16 quantitative factors; Group III and group VI were divided into two sub-groups. Group I was large flowered lines with a single flower, Group IIIa, doubled flowered lines, Group VII, late maturing lines and Group IX, early maturing lines flowering in 17th May. Group VIII were dwarf type lines which has the shortest stem length and leaf length among 14 groups, which are suitable for potted plants. Group XIII had a lot of stems per plant and a large type leaf with leaf length and width. A needle-type leaf was found in Group X, whereas a wide and oval-type leaf in group XII.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.95-95
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• 2017

Lodging is a serious issue in rice production, because it drastically decreases the biomass production and grain yield. Since the Green Revolution, the lodging resistance has been increased by lowering the moment of above-ground parts due to the short culm by the semi-dwarf gene sd1. However, it has been pointed out that sd1 alone has suppressive effects for biomass production and yield. To increase rice yield, the long-culm and large panicle type varieties with a superior lodging resistance need to be developed. To improve the lodging resistance and yield of these type varieties, it would be effective to identify novel alleles for these traits underlying natural variations in rice and to pyramid these alleles to a single rice variety. In order to perform this strategy, we have developed new rice lines derived from crosses among varieties with superior alleles. At first, TULT-gh-5-5 was selected from a cross between strong culm and high biomass variety Leaf Star and high-yielding variety Takanari, and TUAT-32HB was selected from a cross between high-yielding variety Akenohoshi and Takanari. Then, we developed the super thick-culm and super grain-bearing line, LTAT-29 derived from a cross between TULT-gh-5-5 and TUAT-32HB. In the current study, to identify the QTLs and genes relating to the strong culm and the high yield of LTAT-29, we performed QTL analysis using SNPs markers with $F_2$ population derived from a cross between LTAT-29 and Takanari. LTAT-29 has never lodged throughout the growth period despite it had long culms and heavy panicles. LTAT-29 had a larger outer diameter of the culm and twice the size of the section modulus than Takanari. As a result, the bending moment at breaking of LTAT-29 was significantly larger than that of Takanari. Brown rice yield of LTAT-29 was $9.2t\;ha^{-1}$ about 10% higher than that of Takanari due to the larger number of spikelets per panicle. LTAT-29 had a greater number of secondary branches per panicle. In the $F_2$ population between LTAT-29 and Takanari, we found continuous frequency distributions in the section modulus and the spikelet number per panicle. Two QTLs increased the section modulus by the alleles of LTAT-29 were detected on Chr.1L and Chr.2L. One QTL increased the spikelet number per panicle of Takanari by the allele of LTAT-29 was detected on Chr.1L, and two QTLs increased the number of secondary branches per panicle by the alleles of LTAT-29 were detected on Chr.1L and Chr.4L. It was found that the alleles of these QTLs were the japonica type originated from Leaf Star or Akenohoshi. The novel QTLs for the traits related to super thick-culm and super grain-bearing and their combinations could be utilized for improving the lodging resistance and yield in rice varieties.