Drought and high salinity are the most important abiotic factors limiting plant development, growth, and crop productivity in agriculture (Munns and Tester 2008, Sengupta and Majumder 2009, Zhu 2002). As sessile organisms, plants are frequently exposed to drought and high salinity conditions, which alter water potential and cause osmotic stress, leading to serious damage to plant tissues (Bartels and Sunkar 2005, Boudsocq and Lauriere 2005). During exposure to water stress, plants display many physiological changes, such as reduction of water content, closure of stomata, and decreased cell enlargement and growth. In addition, severe and continuous water stress in plants causes the cessation of photosynthesis and disturbance of metabolism, and finally results in death (Nath et al. 2005, Shao et al. 2008). To adapt to these abiotic stress conditions, plants show a variety of responses, including the accumulation of abscisic acid (ABA) and expression of a large number of stress-related proteins (Krasensky and Jonak 2012, Lee and Luan 2012, Skriver and Mundy 1990, Stewart and Lee 1974). Although the cellular and molecular responses to environmental stress are well studied (Hasegawa et al. 2000, Thomashow 1999), the mechanisms underlying the functional modifications caused by osmotic stress are yet to be clarified, because of the complexity at the cellular level as well as at the whole plant level (Ashraf and Harris 2004, Flowers 2004, Foolad et al. 2003a, 2003b, Xiong et al. 2002).

당근의 약배양을 통한 효율적 식물체 재생 시스템을 확립하고자 실험을 수행하였다. 당근 유전형 ‘S&P2342’의 약을 2,4-D와 NAA를 각각 0.1 mg/L 또는 1.0 mg/L 단독 또는 조합 처리한 배지에 치상하여 암조건에서 18주간 배양하였을 때, 2,4-D 1.0 mg/L + NAA 0.1 mg/L 조합처리에서 캘러스 형성율 22.0%, 배형성율 2.0%로 반응이 가장 좋았다. 약으로부터 직접적으로 유도된 1차배를 분리하여 명조건에서 2주간 배양 후 재생배지로 옮겨 배양하였을 때 배양 4주 후부터 발아하다가 생장이 멈추어진 1차배로부터 다수의 2차배가 형성되기 시작하였다. 배양 8주 후 62.5%가 식물체로 전환되었으며, 12주 후 본엽이 전개된 소식물체로 발달하였다. 또한 약으로부터 유도된 캘러스를 분리하여 재생배지에서 배양하였는데, 8주 후 93.9%의 캘러스로부터 1차배가 형성되었으며, 38.8%에서 1차배로부터 2차배 형성을 거쳐 식물체로 전환되었다. 약배양 유래 소식물체(본엽 2매 이상, 초장 2-4 cm)의 건전한 기내 생장을 유도하기 위해 실시한 광도(10, 30, 100, 150 μmol·m-2·s-1) 처리에서 100 μmol·m-2·s-1이 소식물체의 생장에 가장 효과적이었다. 소식물체의 효율적인 기외 활착을 위하여 본엽 4매 이상, 초장 5 cm 이상의 소식물체를 플러그 트레이에 이식 후 플라스틱 재배용기 안에 넣은 다음 온도 (15, 20, 25℃)와 광도(μmol·m-2·s-1) 처리를 각각 2주간에 걸쳐 실시하였는데, 온도 처리에서는 15℃가 기외 활착에 가장 적합하였으며, 광도 처리에서는 100 μmol·m-2·s-1 처리구만 기외 활착이 원활하였다. 결론적으로 당근의 약배양으로부터 직접 배형성 또는 캘러스 단계를 거치는 간접 배형성이 이루어졌으며, 1차배로부터 2차배가 형성된 후 발아를 거쳐 소식물체가 재생되었으며 이를 성공적으로 활착시켜 정상적인 식물체를 얻을 수 있었다. 본 연구를 통하여 당근에서의 약배양으로부터 직접 및 간접 배형성을 통한 식물체 재생 시스템을 구축하였으며, 향후 당근의 F1 잡종 생산을 위한 순수 동형접 합성 유지계통 및 화분친 모본계통의 획득에 활용할 수 있을 것으로 생각된다.

Somatic embryogenic calli were obtained from different native citrus species in Jeju island, South Korea. Undeveloped ovules were cultured on 5 different media, respectively; MSI (MS, modified, with the addition of malt extract 500 mg･L-1 and sucrose 50 g･L-1 and agar 2 g･L-1), MSII (MS, modified, with the addition of malt extract 500 mg･L-1 , kinetin 1 mg･L-1 and sucrose 50 g･L-1 and agar 2 g･L-1), MSIII (MS, modified, with the addition of malt extract 500 mg･L-1, 6-benzyladenine, 3 mg･L-1 and sucrose 50 g･L-1 and agar 2 g･L-1), EME-S (MT, modified, with the addition of malt extract 500 mg･L-1 and sucrose 50 g･L-1 and agar 2 g･L-1), 1/2 EME-S (half concentration of MT marcronutrients, half concentratrion of BH3 marcronutrients, malt extract 500 mg･L-1, glutamine 1.55 g･L-1 and sucrose 50 g･L-1 and agar 2 g･ L-1). Embryogenic calli were induced in the surface of undeveloped ovules in different manners, depending on citrus species and culture conditions. Somatic embryos developed into plantlets with a high frequency. Citrus embryogenic calli can be applied widely to somatic hybridization, genetic transformation, and in vitro germplasm conservation

FGF9/16/20 signaling pathway specify the developmental fates of notochord, mesenchyme, and neural cells in ascidian embryos. Although a conserved Ras/MEK/Erk/Ets pathway is known to be involved in this signaling, the detailed mechanisms of regulation of FGF signaling pathway have remained largely elusive. In this study, we have isolated Hr-Erf, an ascidian orthologue of vertebrate Erf, to elucidate interactions of transcription factors involved in FGF signaling of the ascidian embryo. The Hr-Erf cDNA encompassed 3110 nucleotides including sequence encoded a predicted polypeptide of 760 amino acids. The polypeptide had the Ets DNA-binding domain in its N-terminal region. In adult animals, Hr-Erf mRNA was predominantly detected in muscle, and at lower levels in ganglion, gills, gonad, hepatopancreas, and stomach by quantitative real-time PCR (QPCR) method. During embryogenesis, Hr-Erf mRNA was detected from eggs to early developmental stage embryos, whereas the transcript levels were decreased after neurula stage. Similar to the QPCR results, maternal transcripts of Hr-Erf was detected in the fertilized eggs by whole-mount in situ hybridization. Maternal mRNA of Hr-Erf was gradually lost from the neurula stage. Zygotic expression of Hr-Erf started in most blastomeres at the 8-cell stage. At gastrula stage, Hr-Erf was specifically expressed in the precursor cells of brain and mesenchyme. When MEK inhibitor was treated, embryos resulted in loss of Hr-Erf expression in mesenchyme cells, and in excess of Hr-Erf in a-line neural cells. These results suggest that zygotic Hr-Erf products are involved in specification of mesenchyme and neural cells.

Buckwheat sprout is used as vegetable, and also flour for making noodles, and so on. Currently, information about tissue culture in buckwheat is limited and restricted to micro-propagation. We carried out somatic embryogenesis and plant regeneration using hypocotyl segments as explant of the cultivated buckwheat species, Fagopyrum esculentum which differs from existing studies in the growth regulator combinations used. Maximum callus regeneration was induced on MS medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) 2.0 mg · L-1, benzyladenine (BA) 1.0 mg · L-1 and 3% sucrose. Friable callus was transferred to solidified MS media containing BA (1.0 mg · L-1) with various concentrations of 2,4-dichlorophenoxyacetic acid for the induction of embryogenesis. The optimum concentrations of growth regulators (for regeneration of plantlet) were indole-3-acetic acid (2.0 mg · L-1), Kinetin (1.0 mg · L-1), BA (1.0 mg · L-1). Only 2,4-D did not show any significant effect on callus induction or embryogenesis. Regeneration of embryonic callus varied from 5% to 20%. Whole plants were obtained at high frequencies when the embryogenic calli with somatic embryos and organized shoot primordia were transferred to MS media with 3% sucrose. The main objective of this research was to develop an efficient protocol for plant regeneration for common buckwheat, and to apply in future for genetic transformation.

Cathepsins are members of the multigene family of lysosomal cysteine proteinases and have regulated function in several life processes. The potential role of cathepsin F cysteine gene was expected as protease in the yolk processing mechanism during early developmental stage, but expression analysis was unknown after fertilization. The alignment analysis showed that amino acid sequence of cathepsin F from olive flounder liver expressed sequence tag (EST) homologous to cathepsin F of other known cathepsin F sequences with 87－98% identity. In this study, we examined the gene expression analysis of cathepsin F in various tissues at variety age flounder. Tissue distribution of the cathepsin F mRNA has been shown to be ubiquitous and constitutive pattern regardless of age in each group, although derived from cDNA library using liver sample. The mRNA level of cathepsin F more increased as developmental proceed during embryogenesis and early developmental stage, especially increased in the blastula, hatching stage and 3 days post hatching (dph). As a result, it may suggest that the proteolysis of yolk proteins (YPs) has been implicated as a mechanism for nutrient supply during early larval stages in olive flounder.

Tooth bud is initiated by dental epithelium thickening and invaginated epithelium forms cap-like structure with condensed underlying mesenchyme. From this cap stage, specific epithelial cells form a cluster of non-dividing cells, primary enamel knot (PEK), and this PEK expresses abundant signaling molecules and functions as a signaling center for tooth development. Recently, hundreds of genes involved in tooth development have been reported by advanced genome-wide screening technology, but still remained unidentified genes obstruct elucidation of the precise molecular mechanisms underlying tooth development. In this work, we examined the expression patterns and developmental functions of a novel tooth germ-expressing gene, Dachshund1 (Dach1). Dach1, known as the cell fate regulator via controlling the transcription in various cell types, expressed in PEK region from cap stage to bell stage. In order to evaluate the developmental functions of Dach1 in tooth development, we cultivated the lower first molar at E12.5 for 2 and 4 days with or without treatments of antisense-oligodeoxynucleotides (AS-ODNs) against Dach1. After the knocking down of Dach1, morphological changes and cell physiology such as proliferation, cell death and migration patterns were examined. In addition, the expression levels of PEK-expressing genes such as Bmp2, Bmp7, Fgf4, Shh and Wnt5a were examined by using RT-qPCR and in situ hybridization methods. Based on these results, we suggest that Dach1 would involve in mice tooth morphogenesis through regulating the expressions of PEK related genes and cellular events to form the proper tooth structural formation.

배아발생초기에 분화되는 영양외배엽(TE:trophectoderm)은 태반형성에 기여하는 첫 번째 세포 종류 (type)으로 생식과정에 중요한 역할을 한다. 내부세포괴(ICM)과 더불어 TE로 분화되기 위한 세포운명(cell fate)을 조절하는 전사인자(transcription factor)에 대한 연구는 생쥐, 가축, 인간 등에 대해서 많이 연구 되어 왔다. 하지만 구조형태학적 측면에서 살펴보면 TE의 상피세포화와 포배강 형성에 관한 연구는 주로 tight junction 단백질, 이온 경사 및 물 이동 통로 단백질 등 직접 관련된 개별 유전자/단백질에 대한 연구만 진행되었지만 이들 유전자의 발현을 조절하는 전사인자에 대한 연구는 보고되지 않았다. 본 연구는 RNA 간섭 방법을 이용하여 tight junction과 포배강 형성에 필요한 유전자의 전사인자인 Tcfap2c을 규명하였다. 또한 Tcfap2c는 Cdkn1a(p21)의 발현을 억제하여 상실배에서 배반포로 발달하기 위한 세포증식에 관여한다.

Somatic embryogenesis is a process where a plant or embryo is derived from a single somatic cell or group of somatic cells. Application of this process include: clonal propagation of genetically uniform plant material; elimination of viruses; provision if source tissue for genetic transformation; generation of whole plants from single cells called protoplasts; development of synthetic seed technology. In this study tissue culture was carried out for mass propagation of cassava using somatic embryogenesis. For tissue culture set up, we used cassava variety (“Rayong5”, “Rayong7”, “Rayong9”, “Rayong11”) developed in Rayong Field Crop Research Center(RYFCRC). In induction of callus step, the callus formed from each cassava variety. “Rayong 7“ showed the highest induction rate of 95%, while induction rate of other varies were ranged from 50% to 85%. In the case of weight of callus ”Rayong5“ has the highest weight. Results in the present study would be useful in mass propagation of cassava by somatic embryogenesis.

국내 육성 유채 품종의 소포자 배양을 통한 효율적인 소포자배 생산법의 확립을 위해 '탐미유채'를 대상으로 소포자 배양 시 적당한 꽃봉오리의 크기, 고온처리시간, 배양밀도, 기내 증식조건 등의 배양조건을 구명하고자 실시한 결과, 소포자배 발생은 1핵기말과 2핵기 초기 상태의 소포자가 포함된 3.0~3.5 mm 크기의 꽃봉오리에서 채취한 소포자에서 배발생률이 가장 높았으며, 배지 1 mL 당 약 388개의 소포자 배가 발생하였다. 배양 초기에 32.5℃ 에서 2일간 열처리하였을 때 배발생률이 가장 높았다. 소포자의 배양밀도에 따른 배발생은 5×104 개/mL일 때 가장 높았으며, 배양밀도가 더 이상 높아지면 배발생을 억제하였다. 발생한 소포자배는 0.5mg~cdotL1 NAA와 1mg~cdotL1 BA가 첨가된 MS 고체배지에 치상하여 배양하면 정상적인 신초로 재분화되었고, 발달한 신초를 절취하여 식물성장 조절제가 첨가되지 않은 MS고체배지에서 배양하면 뿌리가 발달하여 정상적인 식물체로 성장하였다.

Ligand-bound nuclear receptors (NRs) recruit coactivators such as members of the p160 steroid receptor coactivator (SRC) family and cyclic AMP responsive element binding protein (CREB)-binding protein (CBP) to specific enhancer elements and activate target gene transcription. In the present study, we isolated a novel SRC from the sea urchin Strongylocentrotus nudus (SnSRC) by using the ligand-binding domain of retinoid X receptor as a bait in a yeast two-hybrid screening. The SnSRC (1992 amino acids) interacted with several NRs, including sea urchin estrogen receptor-related receptor (ERR), human and masu salmon estrogen receptors (ERα), mouse ERRγ, rat glucocorticoid receptor α, and rat thyroid receptor β. Furthermore, preferential interacting domains for ERα in the SnSRC are located in the central LxxLL motifs, revealed by the truncation and mutagenesis studies. Interestingly transient knockdown of the SnSRC gene in the sea urchin embryo using morpoholino antisense RNA induced abnormal phenotypes at gastrulation stage such as the lack of primary invagitation and exogastrulation. Together, the present study identified a novel steroid receptor coactivator in an invertebrate species sea urchin and demonstrated its pivotal role in sea urchin embryogenesis. It will be helpful to uncover evolutional and functional origin of the vertebrate counterpart and the detailed function of steroid receptor coactivator during early embryogenesis.

Buckwheat sprout is used as vegetable, and also flour for making noodles, and so on. Currently, information about tissue culture in buckwheat is limited and restricted to micropropagation. We carried out somatic embryogenesis and plant regeneration using hypocotyl segments as explant of the cultivated buckwheat species Fagopyrum esculentum, differs from existing studies in the growth regulator combinations used. Maximum callus regeneration was induced on MS medium containing 2,4-D(2.0 mg/L) and benzylaminopurine BAP (1.0 mg/L) and 3% sucrose. Friable callus was transferred to solidified MS media containing BAP (1.0 mg/L) and at various concentrations for the induction of embryogensis. The optimum concentrations of additives were IAA (2 mg/L), KIN(1.0 mg/L), BAP (1.0 mg/L), and 3% (w/v) sucrose. Only 2,4-D did not show any significant effect on callus induction or embryogenesis. Regeneration of embryonic callus varied from 5 % to 20%. Whole plants were obtained at high frequencies when the embryogenic calluses with somatic embryos and organized shoot primordia were transferred to MS media with 3% sucrose. Regenerated plants after acclimation will transfer to green house. The main objective of this research was to develop a efficient protocol for plant regeneration for common buckwheat, and to apply in future for genetic transformation.

멍게 유생의 뇌포에는 2개의 감각색소세포인 평형기와 안점 이외에 또 다른 감각세포로 추정되는 수압수용체세포가 존재한다. 수압수용체세포 형성에 관해서는 현재까지 거의 알려진 것이 없다. 본 연구에서는 수압수용체세포 형성에서 FGF 신호전달 과정의 관련성을 조사했다. 수정란에 Hr-FGF9/16/20 antisense MO를 미세주입했을 때, 발생한 유생에서 수압수용체세포 특이적 Hpr-1 항원의 발현이 검출되지 않았다. 32세포기부터 FGF 수용체 억제제

구조적으로 estrogen 수용체(estrogen receptor, ER)와 유사한 estrogen receptor-related receptor(ERR)는 포유동물에서 배발생 후기에 외배엽 형성과 관련되어 있다고 알려진 고아핵수용체(orphan nuclear receptor)이다. ERR은 ER과 DNA binding domain의 보존성은 유사하지만, ligand 결합 및 전사 활성은 다르다. 포유동물의 ERR에 관한 연구에 비하여 해양 무척추동물의

An efficient somatic embryogenesis and plant regeneration protocol was developed for Schisandra chinensis Baill, using embryogenic cell suspensions and optimized media conditions. Friable embryogenic callus was induced from cotyledonary leaf and hypocotyl explants of 7 days old seedlings on MS agar medium supplemented with 1.0 to 4.0 mg l-1 of 2,4-dichlorophenoxyacetic acid (2,4-D). Fast growing and well dispersed embryogenic cell suspensions were developed within two months when embryogenic calli were transferred to MS liquid medium containing 1.0 mg l-1 2,4-D. One third strength of MS medium was the best for both overall growth and development of somatic embryos in liquid culture. Over 3400 viable somatic embryos were produced from each 150 ml flask with an initial cell density of 30 mg in 30 ml medium. Germinated somatic embryos developed in liquid medium converted into plantlets after transferred to half-strength MS semi-solid medium. Approximately 90% of the converted plantlets were successfully transplanted to soil and grew into fertile plants.