• Journal of Life Science
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• v.3 no.1
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• pp.2-8
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• 1993

천연화합물과 합성화합물은 모두 합쳐서 식물생장조절제라 부르고 이들 화합물은 경우에 따라 식물의 기간들의 생장율을 촉진하거나 억제한다. 호르몬이란 용어는 천연적으로 발생하는 색물생장 조절제에 국한되는 것이다. 실제의 응용에 있어서 합성된 생장조절제가 사용되는 것은 이 물질이 생체내에서 안정도가 더 크기 때문이다. 따라서, 합성물질은 식물 호르몬의 구조적인 유사성으로 흉내를 내거나 내생 호르몬들의 생합성, 전류, 및 대사를 조정해서 그 수준을 조절하게 된다. 그래서, 식물생장 조절물질들의 기능과 가능력을 이해하기 위해서 분자수준에서 식물호르몬들의 작용의 양상을 고찰한다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.10-10
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• 2020

전 지구적으로 생물다양성의 지속적인 감소 추세에 따른 생물자원의 중요성이 증가하는 시점에서, 식물 유전자원의 종 다양성 보존과 지속가능한 이용을 위한 체계적이고 현실적인 방안 마련이 절실한 실정이다. 국내에서도 2017년에 유전자원 접근 및 이익 공유에 대한 나고야 의정서가 발효됨에 따라 식물유래 BT산업 소재의 국내 자급이 불가피해진 상황이며, 더불어 국토의 생태복원에 적합한 식물 소재 개발의 중요성이 대두되면서 자생식물의 종자 수급기반 대책은 국가적 차원에서 중대한 과제라 할 수 있다. 우리나라는 면적 대비 높은 식물 종 다양성을 보이며, 이는 종자의 휴면유형 또한 다양하고 복잡할 수 있다는 것을 의미한다. 따라서 식물유전자원으로써의 보존 및 국가 경제적 이익을 위한 종자 활용, 산업화를 위해서는 종자의 생리적 특성에 기반 한 데이터베이스의 축적과 효과적인 활용을 위한 종자 휴면유형 분류 및 적정 휴면타파 조건을 확립할 필요가 있다. 현재까지 다양한 식물종에서 종자 휴면의 하위 카테고리가 계속적으로 세부 분류되고 있으나, 아직까지 밝혀지지 않은 세부 휴면유형에 의해 많은 유용 식물자원의 활용이 제한적이다. 종자의 휴면유형은 크게 외생휴면(Exogenous dormancy)과 내생휴면(Endogenous dormancy)으로 분류되며, 국내에서는 내생휴면에 대한 연구가 주를 이루고 있다. 한편 외생휴면은 물리적 휴면(Physical dormancy), 기계적 휴면(Mechanical dormancy) 및 화학적 휴면(Chemical dormancy)으로 세부 분류되며, 기계적 휴면과 화학적 휴면은 내생휴면인 생리적 휴면(Physiological dormancy)에 포함되어야 한다는 의견도 있다. 물리적 휴면 종자에서는 water-gap 복합체의 존재 등에서 원인을 찾을 수 있으나, 발아억제 호르몬에 기인하는 화학적 휴면 및 종(과)피 또는 배유에 의한 기계적 휴면은 배의 성장잠재력과 발달에 의해 타파될 수 있다. 이와 같이 실제로 많은 식물 종에서 다양하게 존재하는 외생휴면 유형에 대해 내생휴면과는 명확히 다른 방식으로 접근되어야 하므로, 다년간의 체계적 연구를 통해 미흡한 종자생리 연구 분야를 보완하고 자생식물의 종자 활용도를 높일 수 있을 것으로 기대한다.

• Horticultural Science & Technology
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• v.29 no.1
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• pp.1-9
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• 2011

This study was performed to investigate the role of plant growth substances on the bulbing of cold type of garlic (Allium sativum L. cv. Uiseongmaneul) during long and short day conditions. The change in endogenous plant hormones such as abscisic acid (ABA), jasmonic acid (JA) and sugar contents in leaf blade and sheath was examined during the growth stage from bulb differentiation (starting at April 16) to bulbing (April 24 to May 18) in cold type of garlic. In the long day condition, ABA contents were higher than short day condition and ABA contents of leaf sheath were higher than leaf blade. ABA contents of growth stage in garlic were not changed during growth stage from April 16 to May 2, however it rapidly increased during bulbing (May 2 to May 18). On the other hand, endogenous JA contents in short day condition did not change in long day condition, it increased from April 16 to May 2. JA contents in the leaf sheath (33.85-62.04 $ng{\cdot}g^{-1}$ DW) were higher than leaf blade (15.39-30.04 $ng{\cdot}g^{-1}$ DW). These results showed that garlic bulb differentiation and bulbing was induced by JA in leaf sheath. In long day condition, total sugar contents in the leaf blade were increased from bulb differentiation (April 16) to bulbing (May 4) and it was decreased during bulbing (May 4 to May 18) while the total sugar content in leaf sheath were gradually increased from bulb differentiation (April 16) to bulbing (May 18). In conclusion, our results showed that there is a significant correlation between the bulb development of garlic and hormonal content in the leaf sheath.

• The Korean Journal of Mycology
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• v.43 no.1
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• pp.71-76
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• 2015

Aquatic plant Hydrocharis dubia (Blume) Backer was collected from the Dalsung wetland in Daegu. Sixteen endophytic fungi with different colony morphologies were isolated from the roots of aquatic plants. Waito-c rice (WR) seedlings were treated with fungal culture filtrates (FCF) for screening plant growth-promoting activity. In the results, HD1008 strain isolated from aquatic plant showed highest plant growth-promoting activity. The FCF of HD1008 strain was analyzed using gas chromatography mass spectrometry (GC/MS) with selected ion monitoring (SIM). Analysis of the FCF of HD1008 strain found that it contained gibberellins (GA) ($GA_1$, 1.2 ng/100 mL; $GA_4$, 5 ng/100 mL). Phylogenetic tree of HD1008 strain was constructed by partial internal transcribed spacer (ITS) region and partial beta-tubulin gene sequences. Therefore, we describe HD1008 strain as a new gibberellin-producing Penicillium trzebinskii based on morphological and molecular characteristics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.42-48
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• 1997

Ten days old rice seedlings were treated with NaCl and the contents of endogenous hormones such as GA$_3$, ABA, IAA and zeatin were measured by ELISA. Water content and seedling growth were decreased as the salt concentration was increased. GA$_3$ increased up to 24 hours after NaCl treatment and decreased thereafter. ABA was raised by four times in 48 hours after NaCl treatment. IAA and zeatin decreased as the NaCl concentration and duration of treatment increased. GA$_3$ and ABA showed positive and negative correlation with the water content in the plant tissue, respectively.

• Journal of Life Science
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• v.7 no.3
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• pp.205-211
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• 1997

The possibility of circadian production of plant hormone gibberellin (GA0 was examined in phytochrome B mutant (plyB-1) and wild-type sorghum. GA$_{12}$, GA$_{20}$ and GA$_{1}$ levels were found to cycle circadianly in both phyB-1 and wild-type. The periods (33 h) of GA$_{20}$ and GA$_{1}$ cycling in constant light were longer than normal photoperiods in both genotypes and typical average free running periods in plants of 22 to 28 h. The biological clock was thus shown to function properly in phyB-1. However, circadian regulation of GAs productions were not clear as compared to circadian ethylene regulation reported by Lee (1996). Although, in sorghum, EOD FR treatment hasten floral inititation, the differences in GA concentrations between treatments and untreated control were generally less dramatic than expected. Thus, it can be concluded that FR does not act primarily by changing absolute levels of GAs but rather by increasing flowering responsiveness to GAs.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.14-20
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• 2015

Coastal plant species, Plantago camtschatica Cham. native to the coastal region of the East Sea were sampled and then morphologically different 20 endophytic fungal strains were purely isolated. Phylogenetic analysis of isolates was done by the Bayesian program based on sequenced internal transcribed spacer (ITS-rDNA) region. Culture filtrates of each of 20 isolates were treated to Waito-c rice (WR) seedlings for verifying plant growth-promoting activity, respectively. As the results, E/PC/10/1 strain showed the highest plant growth-promoting activity among them. The culture filtrate of the strain E/PC/10/1 was revealed as containing gibberellins ($GA_1$, $GA_3$, $GA_4$) by using HPLC, and gas GC/MS with selected ion monitoring (SIM). Finally, this strain was identified as novel Penicillium spinulosum species that producing new GAs with microscopic observation and further molecular analysis with beta-tubulin gene sequence.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.329-331
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• 2017

Bacillus velezensis YC7010 is an endophytic bacterium isolated from the rice rhizosphere in Jinju, Republic of Korea, with properties conductive to growth promotion, antibiosis and induced systemic resistance to significant, soil-borne rice fungal and bacterial pathogens. The genome of B. velezensis YC7010 comprises a 3,975,683 bp circular chromosome which consists of 3,790 protein-coding genes (86tRNA and 27rRNA genes). Based on genomic analysis, we identified genes involved in colonization and establishment inside the plant, biosynthesis of antibiotic compounds such as surfactin, plipapastatin, bacillibactin, and bacillaene, as well as the production of the phytohormones and volatile compounds which serve to promote the plants growth and development.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.750-756
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• 2010

This study was performed to investigate the role of phytohormones in the bulbing of garlic in order to assess the yield and quality. The effect on endogenous plant hormones such as gibberellin (GA) content was also examined during growth stage i.e. clove differentiation to bulbing in garlic. More than 18 gibberellins in garlic were identified with extensive gas chromatograph-mass spectrometry-selected ion monitoring (GC-MS-SIM) quantitative analysis. The results showed that GAs were biosynthesized by both non C-13 hydroxylation pathway (NCH) and early C-13 hydroxylation pathway (ECH) in garlic plant. It was also revealed that NCH pathway leading to synthesis of bioactive $GA_4$ was the more prominent GA biosynthesis pathway than ECH pathway in which bioactive $GA_1$ was synthesized. Total GAs level was gradually increased from clove differentiation to bulbing and later decreased, which portrays the active role of GA in differentiation. The biosynthesis ratio of bioactive $GA_4$ and $GA_1$ concentration was similar to that of total GAs content, which was closely related with bulb development in garlic.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.32-39
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• 2016

Coastal plant species Tetragonia tetragonoides (Pall.) Kuntze native to the Dokdo islands was sampled and then 17 endophytic fungi were purely isolated based on morphological differences. The fungal isolates were characterized by their growth properties under NaCl concentration or pH gradient. Culture filtrates of the 17 fungal isolates were treated to Waito-c rice (WR) seedlings for verifying plant growth-promoting activity. As the results, YH103 strain showed the highest plant growth-promoting activity among them. Phylogenetic analysis of the isolates was done by the maximum likelihood method based on partial internal transcribed spacer region (ITS region: contaning ITS1, 5.8S, and ITS2), beta-tubulin (BenA), and calmodulin (CaM) gene sequences. Chromatographic analysis of the strain YH103 culture filtrate showed the existence of gibberellins ($GA_4$, $GA_7$, $GA_8$, and $GA_{19}$). Finally, the strain YH103 was identified as Aspergillus tubingensis by microscopic observation and molecular analysis and, to our knowledge, this is the first report of GAs producing A. tubingensis.