• Korean Journal of Weed Science
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• v.15 no.4
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• pp.247-253
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• 1995

The herbicide butachlor [N-(butoxymethyl)-2-chloro-N-(2,6-di-methylphenyl) acetamide] is widely used by farmers as a tool for weed management of transplanted rice(Oryza sativa L.) in Taiwan. The herbicide did not stop germination of rice and weed seeds, but strongly inhibited the subsequent growth of young shoots and roots. The inhibition was also strong on established seedlings. However, they could recover to normal growth after the herbicide effect disappeared. Butachlor greatly decreased the endogenous indole-3-acetic acid (IAA) but increased the endogenous abscisic acid (ABA) contents of rice seedlings. Addition of lAA into growth medium (Hoagland's solution) partly relieved growth inhibition. Pretreatment of both gibberellic acid ($GA_3$) and IAA 24 hours before butachlor treatment almost completely alleviated the butachlor-interfere with GA and/or IAA metabolism or their action resulting in the growth inhibition of rice. Butachlor was readily absorbed by rice roots. During 24 hours of uptake experiment, 32% of the applied herbicide was absorbed. Pretreatment of the herbicide for 2 days did ncx affect the absorption. Of the absorbed herbicide, 80% remained in roots, only 20% transported into shoots, and more than 50% was metabolized to water soluble substances. Thin-layer chromatographic (TLC) analysis indicated that the Rf value of the most abundant metabolite was butachlor-glutathione conjugate. Rice, barnyardgrass (Echinochloa crus-galli (L.) Beauv.), and monochoria (Monochoria vaginalis Presl) seedlings contained relatively high level of non-protein thiols, while the glutathione S-transferase (GST) activity was found highest in rice, barnyardgrass the next, monochoria the lowest. The difference in GST activity among these species might be related to their sensitivity to butachlor.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.100-108
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• 2016

An auxin-producing bacteria (strain 5-1) was isolated from button mushroom compost in Boryeong-Si, Chungcheongnam-Do. The 5-1 strain was classified as a novel strain of Enterobacter aerogenes based on chemotaxonomic and phylogenetic analyses. The isolated E. aerogenes 5-1 was confirmed to produce indole-3-acetic acid (IAA), one of the auxin hormones, using TLC and HPLC analyses. When the concentration of IAA was assessed by performing HPLC quantitative analysis, a maximum concentration of IAA of $109.9mgL^{-1}$ was detected in the culture broth incubated in R2A medium containing 0.1% L-tryptophan for 24 h at $35^{\circ}C$. Acidification of the culture was deemed caused by an increase of IAA because a negative relationship between IAA production and pH was observed. Supplementation with a known precursor of IAA production, L-tryptophan, appeared to induce maximal production at 0.1% concentration, but it reduced production at concentrations above 0.2%. To investigate the growth-promoting effects to crops, the culture broth of E. aerogenes 5-1 was used to inoculate water cultures and seed pots of mung bean and lettuce. In consequence, adventitious root induction and root growth of mung bean and lettuce were two times higher than those of the control.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.37-42
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• 2012

Improvement of plant growth by Methylotrophic bacteria can be influenced through alterations in growth modulating enzymes or hormones, especially by decreasing ethylene levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC) deaminase or by production of indole-3-acetic acid (IAA). In this study, the effect of seven strains of Methylobacterium on seedling ethylene emission of tomato and red pepper plants was evaluated under greenhouse condition. Ethylene emission was lowest in Methylobacterium oryzae CBMB20 inoculated tomato plants and CBMB110 inoculated red pepper plants at 47 days after sowing (DAS). However, at 58 DAS all inoculated plants showed almost similar pattern of ethylene emission. Methylobacterium inoculated tomato and red pepper plants showed significantly less ethylene emission compared to control. Our results demonstrated that Methylobacterium spp. inoculation promotes plant growth due to the reduction of ethylene emission and therefore can be potentially used in sustainable agriculture production systems.

• Journal of the Korean Wood Science and Technology
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• v.17 no.3
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• pp.61-66
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• 1989

포플라 세포(細胞)의 Sucrose gradient 원심분리(遠心分離)에 나타난 세포(細胞)분획은 6개의 band 및 침전으로 분리(分離) 되었다. Peroxidase의 활성변화(活性變化)는 휴면기(休眼期)에 높아졌으며, 자발적(自發的) 휴면(休眠)이 타파되면서 낮아지기 시작하였다. 휴면기(休眠期)에 급격히 높아진 Peroxidase 활성(活性)은 Peroxidative 활성(活性)을 지닌 세포내(細胞內) Microbody에 존재(存在)하는 것으로 사료된다. Catalase의 활성(活性)은 11월(月), 12 월(月) 1월(月)의 휴면기(休眼期)에 활성(活性)이 낮았으며. IAA의 농도는 휴면초기(休眼初期)에 감소하기 시작하여, 12월(月)에 최저(最低)가 되었다. 자연휴면(自然休眠)이 타파된 1월(月)부터는 IAA 농도가 증가하기 시작하여 4월(月)의 발아기(發芽期)까지 계속되었다. 이와같은 Peroxidase, Catalase를 비롯한 IAA의 변화(變化)는 봄철의 발아(發芽) 및 재생장(再生長)과 가을철 휴면조절(休眠調節)에 영향을 미치는 것으로 사료된다.

• Journal of Mushroom
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• v.13 no.4
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• pp.275-281
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• 2015

An auxin-producing bacteria (A-1) was isolated from soils of Oyster mushroom farmhouse in Daejeon city, South Korea. The strain A-1 was classified as a novel strain of Ochrobactrum anthropi based on a chemotaxanomic and phylogenetic analyses. The isolate was confirmed to produce indole-3-acetic acid (IAA), one of auxin hormones, by TLC and HPLC analyses. The maximum concentration of IAA, $5.6mg\;L^{-1}$ was detected from the culture broth of O. anthropi A-1 incubated for 24 h at $35^{\circ}C$ in R2A broth containing 0.1% L-tryptophan. To investigate the growth-promoting effects to the crops, the culture broth of O. anthropi A-1 was inoculated to water cultures and seed pots of mung bean as well as lettuce. In consequence, the adventitious root induction and root growth of mung bean and lettuce were 2.7 and 1.4 times higher than those of the non-inoculated, respectively.

• Journal of Plant Biotechnology
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• v.43 no.2
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• pp.255-260
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• 2016

This research was conducted to improve the cold tolerance of the gerbera cv. Gold Eye by introduction of the Arabidopsis $Ca^{2+}/H^+$ antiporter gene (CAX1) via Agrobacterium-mediated transformation. Prior to genetic transformation, we optimized a combination of plant growth regulators; $1.0mgl^{-1}$ 6-Benzyladenine (BA) and $0.1mgl^{-1}$3-indole-acetic acid (IAA) were found to lead to proper in vitro shoot regeneration from petiole explants. In addition, $50mgl^{-1}$ kanamycin was determined to be the minimal concentration useful for selection of putative transgenic plants. In this study, transgenic gerbera expressing the Arabidopsis $Ca^{2+}/H^+$ antiporter gene (CAX1) were obtained using the optimized concentrations. We expect that introduction of the gene to the cultivar will improve cold tolerance, which will be important in the winter months.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.441-454
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• 2021

Fungal diseases including anthracnose, stem rot, blight, wilting, and root rot of crops are caused by phytopathogens such as Colletotrichum species, Sclerotinia sclerotiorum, Phytophthora species, and Fusarium oxysporum and F. solani which threaten the production of chili pepper. In this study, to identify biological control agents (BCAs) of phytopathogenic fungi, potentially useful Bacillus species were isolated from the field soils. We screened out five Bacillus strains with antagonistic capacity that are efficiently inhibiting the growth of phytopathogenic fungi. Bacillus species were characterized by the production of extracellular enzymes, siderophores, and indole-3-acetic acid (IAA). Furthermore, the influence of bacterial strains on the plant growth promoting activity and seedling vigor index were assessed using Brassica juncea as a model plant. Inoculation with Bacillus subtilis SRCM 121379 significantly increased the length of B. juncea shoots and roots by 45.6% and 52.0%, respectively. Among the bacterial isolates, Bacillus subtilis SRCM 121379 showed the superior enzyme activities, antagonistic capacity and plant growth promoting effects. Based on the experimental results, Bacillus subtilis SRCM 121379 (GenBank accession no. NR027552) was finally selected as a BCA candidate.

• Mycobiology
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• v.43 no.1
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• pp.49-56
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• 2015

The present study is the first report on the isolation of Penicillium menonorum from rhizosphere soil in Korea and its identification based on morphological characteristics and internal transcribed spacer gene sequence. The fungal isolate was named KNU-3 and was found to exhibit plant growth-promoting (PGP) activity through indole acetic acid (IAA) and siderophore production, as well as P solubilization. KNU-3 produced 9.7 mg/L IAA and solubilized 408 mg of $Ca_3PO_4/L$, and inoculation with the isolate significantly (p < 0.05) increased the dry biomass of cucumber roots (57%) and shoots (52%). Chlorophyll, starch, protein, and P contents were increased by 16%, 45%, 22%, and 14%, respectively, compared to plants grown in uninoculated soil. The fungus also increased soil dehydrogenase (30%) and acid phosphatase (19%) activities. These results demonstrate that the isolate KNU-3 has potential PGP attributes, and therefore it can be considered as a new fungus to enhance soil fertility and promote plant growth. Moreover, the discovery of PGP ability and traits of this fungus will open new aspects of research and investigations. In this study, plant growth promotion by P. menonorum KNU-3 is reported for the first time in Korea after its original description.

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1755-1764
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• 2016

The application of Bacillus sp. in the biological control of plant soilborne diseases has been shown to be an environmentally friendly alternative to the use of chemical fungicides. In this study, the effects of bioorganic fertilizer (BOF) fortified with Bacillus amyloliquefaciens SQY 162 on the suppression of tomato bacterial wilt were investigated in pot experiments. The disease incidence of tomato wilt after the application of BOF was 65.18% and 41.62% lower at 10 and 20 days after transplantation, respectively, than in the control condition. BOF also promoted the plant growth. The SQY 162 populations efficiently colonized the tomato rhizosphere, which directly suppressed the number of Ralstonia solanacearum in the tomato rhizosphere soil. In the presence of BOF, the activities of defense-related enzymes in tomato were lower than in the presence of the control treatment, but the expression levels of the defense-related genes of the plants in the salicylic acid and jasmonic acid pathways were enhanced. It was also found that strain SQY 162 could secrete antibiotic surfactin, but not volatile organic compounds, to suppress Ralstonia. The strain could also produce plant growth promotion compounds such as siderophores and indole-3-acetic acid. Thus, owing to its innate multiple-functional traits and its broad biocontrol activities, we found that this antagonistic strain isolated from the tobacco rhizosphere could establish itself successfully in the tomato rhizosphere to control soilborne diseases.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.16-21
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• 2012

Since many pesticides cause various health and environmental problems, alternative measures to replace them are needed, and the bacteria producing the antifungal substances can be one of them. In this study, several rhizobacteria were isolated and their antifungal activities against some important plant pathogenic fungi were examined. Pseudomonas otitidis TK1 and Paenibacillus peoriae RhAn32 inhibited the growth of Fusarium oxysporum f. sp. niveum and F. oxysporum f. sp. lycopersici by 49.8% and 45.6%, and 45.1% and 48.3%, respectively compared to those of the control. P. peoriae RhAn32 also decreased the growth of F. oxysporum f. sp. raphani by 37.5%. This growth inhibition might be due to the production of antifungal substances, such as siderophore, hydrogen cyanide and chitinase, which were produced by these rhizobacteria. P. otitidis TK1 also produced plant growth hormones indole acetic acid and indole butyric acid at $293.41{\mu}g/mg$ protein and $418.53{\mu}g/mg$ protein, respectively. When P. otitidis TK1 and B. cereus TK2 were inoculated together with F. oxysporum f. sp. lycopersici to the 4 weeks grown tomato seedlings and incubated additional 8 weeks, the stem lengths of tomato increased up to 45.7% and 55.3% and root lengths were raised to 64.9% and 60.8%, respectively than those of the control group. The wet weights increased by 118% and 182%, respectively compared to the control group.