• Journal of Sericultural and Entomological Science
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• v.30 no.1
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• pp.1-7
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• 1988

Flower buds of the mulberry(Morus alba L., Morus bombycis Koidz.) were cultured under different conditions such as basal media, and various concentrations of plant growth substances. Effects of the culture conditions on growth of the buds and organ regeneration were investigated and the result obtained are as follows: Murashige and Skoog(M.S.) medium was more effective on budding and growth of female(Keomseolppong) and male(Kaeryangppong) flower buds isolated directly from branches, compared to Greshoff & Doy(G.D.) and Wolter & Skog(W.S.) media. The growth of the female buds was promoted at higher concetration of benzyl amino purine(BAP) i.e., 2.0ppm. The female and male buds cultured after cuuting for seven days showed better growth than those without cutting treatment. The females and the males bloomed to form healthy stigmas and anthers, respectively, when cultured on M.S. media containing high Kinetin with low concentration of indole acetic acid(IAA).

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.246-253
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• 2012

The purpose of this study was to investigate the molecular diversity of rhizobacteria associated with ginseng of varying age levels and their plant benefiting attributes. A total of 143 different isolates belonging to 15 different bacterial genera were recovered. Although variation was found in the rhizobacterial community due to age of the plant, majority of bacteria belong to Firmicutes (58%). In which, Bacillus was found to be the predominant genus irrespective of age of the ginseng. To assess the plant benefiting attributes, 30 representative isolates were selected. The results indicated that some of the isolates could exhibit multiple plant growth promoting traits like secretion of cell wall degrading enzymes, production of indole-3-acetic acid, synthesis of siderophores, solubilization of phosphates and soil pathogens inhibition. It can be suggested that strains of B. subtilis, B. amyloliquefaciens, B. velezensis, and B. licheniformis were positive for all the above traits, which have potential to be used as plant growth promoting inoculants to improve ginseng crop in the future.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1156-1167
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• 2018

The aim of this study was to isolate and characterize lead (Pb)-solubilizing bacteria from heavy metal-contaminated mine soils and to evaluate their inoculation effects on the growth and Pb absorption of Brassica juncea. The isolates were also evaluated for their plant growth-promoting characteristics as well as heavy metal and salt tolerance. A total of 171 Pb-tolerant isolates were identified, of which only 15 bacterial strains were able to produce clear haloes in solid medium containing PbO or $PbCO_3$, indicating Pb solubilization. All of these 15 strains were also able to dissolve the Pb minerals in a liquid medium, which was accompanied by significant decreases in pH values of the medium. Based on 16S rRNA gene sequence analysis, the Pb-solubilizing strains belonged to genera Bacillus, Paenibacillus, Brevibacterium, and Staphylococcus. A majority of the Pb-solubilizing strains were able to produce indole acetic acid and siderophores to different extents. Two of the Pb-solubilizing isolates were able to solubilize inorganic phosphate as well. Some of the strains displayed tolerance to different heavy metals and to salt stress and were able to grow in a wide pH range. Inoculation with two selected Pb-solubilizing and plant growth-promoting strains, (i.e., Brevibacterium frigoritolerans YSP40 and Bacillus paralicheniformis YSP151) and their consortium enhanced the growth and Pb uptake of B. juncea plants grown in a metal-contaminated soil. The bacterial strains isolated in this study are promising candidates to develop novel microbe-assisted phytoremediation strategies for metal-contaminated soils.

• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1614-1623
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• 2010

Bacteria were isolated from roots of sugarcane varieties grown in the fields of Punjab. They were identified by using API20E/NE bacterial identification kits and from sequences of 16S rRNA and amplicons of the cpn60 gene. The majority of bacteria were found to belong to the genera of Enterobacter, Pseudomonas, and Klebsiella, but members of genera Azospirillum, Rhizobium, Rahnella, Delftia, Caulobacter, Pannonibacter, Xanthomonas, and Stenotrophomonas were also found. The community, however, was dominated by members of the Pseudomonadaceae and Enterobacteriaceae, as representatives of these genera were found in samples from every variety and location examined. All isolates were tested for the presence of five enzymes and seven factors known to be associated with plant growth promotion. Ten isolates showed lipase activity and eight were positive for protease activity. Cellulase, chitinase, and pectinase were not detected in any strain. Nine strains showed nitrogen fixing ability (acetylene reduction assay) and 26 were capable of solubilizing phosphate. In the presence of 100 mg/l tryptophan, all strains except one produced indole acetic acid in the growth medium. All isolates were positive for ACC deaminase activity. Six strains produced homoserine lactones and three produced HCN and hexamate type siderophores. One isolate was capable of inhibiting the growth of 24 pathogenic fungal strains of Colletotrichum, Fusarium, Pythium, and Rhizoctonia spp. In tests of their abilities to grow under a range of temperature, pH, and NaCl concentrations, all isolates grew well on plates with 3% NaCl and most of them grew well at 4 to $41^{\circ}C$ and at pH 11.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1218-1230
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• 2021

Cold-adapted plant growth-promoting bacteria (PGPB) with multiple functions are an important resource for microbial fertilizers with low-temperature application. In this study, culturable cold-adapted PGPB strains with nitrogen fixation and phosphorus solubilization abilities were isolated. They were screened from root and rhizosphere of four dominant grass species in nondegraded alpine grasslands of the Qilian Mountains, China. Their other growth-promoting characteristics, including secretion of indole-3-acetic acid (IAA), production of siderophores and ACC deaminase, and antifungal activity, were further studied by qualitative and quantitative methods. In addition, whether the PGPB strains could still exert plant growth-promoting activity at 4℃ was verified. The results showed that 67 isolates could maintain one or more growth-promoting traits at 4℃, and these isolates were defined as cold-adapted PGPB. They were divided into 8 genera by 16S rRNA gene sequencing and phylogenetic analysis, of which Pseudomonas (64.2%) and Serratia (13.4%) were the common dominant genera, and a few specific genera varied among the plant species. A test-tube culture showed that inoculation of Elymus nutans seedlings with cold-adapted PGPB possessing different functional characteristics had a significant growth-promoting effect under controlled low-temperature conditions, including the development of the roots and aboveground parts. Pearson correlation analysis revealed that different growth-promoting characteristics made different contributions to the development of the roots and aboveground parts. These cold-adapted PGPB can be used as excellent strain resources suitable for the near-natural restoration of degraded alpine grasslands or agriculture stock production in cold areas.

• Journal of Ginseng Research
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• v.45 no.2
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• pp.218-227
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• 2021

Background: Panax ginseng is one of the most important medicinal plants and is usually harvested after 5 to 6 years of cultivation in Korea. Heavy metal (HM) exposure is a type of abiotic stress that can induce oxidative stress and decrease the quality of the ginseng crop. Siderophore-producing rhizobacteria (SPR) may be capable of bioremediating HM contamination. Methods: Several isolates from ginseng rhizosphere were evaluated by in vitro screening of their plant growth-promoting traits and HM resistance. Subsequently, in planta (pot tests) and in vitro (medium tests) were designed to investigate the SPR ability to reduce oxidative stress and enhance HM resistance in P. ginseng inoculated with the SPR candidate. Results: In vitro tests revealed that the siderophore-producing Mesorhizobium panacihumi DCY119^T had higher HM resistance than the other tested isolates and was selected as the SPR candidate. In the planta experiments, 2-year-old ginseng seedlings exposed to 25 mL (500 mM) Fe solution had lower biomass and higher reactive oxygen species level than control seedlings. In contrast, seedlings treated with 10⁸ CFU/mL DCY119^T for 10 minutes had higher biomass and higher levels of antioxidant genes and nonenzymatic antioxidant chemicals than untreated seedlings. When Fe concentration in the medium was increased, DCY119^T can produce siderophores and scavenge reactive oxygen species to reduce Fe toxicity in addition to providing indole-3-acetic acid to promote seedling growth, thereby conferring inoculated ginseng with HM resistance. Conclusions: It was confirmed that SPR DCY119^T can potentially be used for bioremediation of HM contamination.

• The Plant Pathology Journal
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• v.38 no.2
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• pp.115-130
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• 2022

Though information exists regarding the pathogenesis of the shot-hole disease (SH) in flowering cherry (FC), there has been a lack of research focusing on SH management. Therefore, here, we investigated the inhibitory activities of antagonistic bacteria against SH pathogens both in vitro and in vivo as well as their biochemical characteristics and bioactive compounds. Two biosurfactant-producing bacterial antagonists, identified as Bacillus velezensis strains JCK-1618 and JCK-1696, exhibited the best effects against the growth of both bacterial and fungal SH pathogens in vitro through their cell-free culture filtrates (CFCFs). These two strains also strongly inhibited the growth of the pathogens via the action of their antimicrobial diffusible compounds and antimicrobial volatile organic compounds (VOCs). Crude enzymes, solvent extracts, and biosurfactants of the two strains exhibited antimicrobial activities. Liquid chromatography/electrospray ionization time-of-flight mass spectrometric analysis of the partially purified active fractions revealed that the two antagonists produced three cyclic lipopeptides, including iturin A, fengycin A, and surfactin, and a polyketide, oxydifficidin. In a detached leaf assay, pre-treatment and co-treatment of FC leaves with the CFCFs led to a large reduction in the severity of the leaf spots caused by Epicoccum tobaicum and Bukholderia contaminans, respectively. In addition, the two antagonists produced indole-3-acetic acid, siderophore, and a series of hydrolytic enzymes, along with the formation of a substantial biofilm. To our knowledge, this is the first report of the antimicrobial activities of the diffusible compounds and VOCs of B. velezensis against the SH pathogens and their efficiency in the biocontrol of SH.

• Journal of Ginseng Research
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• v.20 no.1
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• pp.83-87
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• 1996

The effects of gibberilin ($GA_3$) on levels of endogenous indole-3-acetic acid (IAA) and zeatin in both fresh and stratified American ginseng (Panax quinquefolium) seeds were investigated. In our first experiment, the fresh seeds were stratified after soaked in 80 ppd $GA_3$ solution for 24 hours. We found that the IAA concentration in embryo increased by 50.7% and 82.1% respectively at the 120th day and the 188th day of stratification, and the zeatin concentration also increased by 3.8% and 51.6% respectively. In our second experiment, we treated the seeds after 134 days stratification with 80 ppm GA3 for 24 hours and then continued to stratify them. We found that the IAA concentration in embryo increased by 32.9% and 17.7% respectively at the 164th day and the 208th day of stratification while zeatin concentration increased by 22.7% and 30.6% respectively In our another experiment, we studied the effects of $GA_3$, abscislc acid (ABA) and GA, plus ABA on germination rate of seeds treated with these plant hormones during stratification. We found that when the stratified seeds whose ratio of embryo had reached 75% were treated with 80 ppm GA3 for 24 hours and then were allowed to be stratified for another 88 days, the weight and length of embryo (p < 0.05), and germination rate (p < 0.01) increased. In contrast, the 25 ppm ABA treated with for 24 hours was found to Inhibit the growth of embryo (p < 0.05) and reduce the germination rate (p < 0.05) . The experiment of combination treatment of $GA_3$ and ABA showed that $GA_3$ could relieve the inhibitory effects of the ABA on the development of the seeds.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.162-167
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• 1986

This experiment was conducted to determine the effect of light, organophosphorus compounds and plant growth regulators on phytotoxicity of pendimethalin (3,4-dimethyl-2,6-dinitro-N-1-ethyl propylamine) in rice (Oryza saliva L.). The phytotoxicity of pendimethalin on post-germination growth of rice was greatly reduced by light treatment. This effect resulted from photodecomposition of pendimethalin. Antidoting activity on phytotoxicity of pendimethalin varied with the kind of organophosphorus compounds used and the application time. The greatest antidoting effect was obtained from edifenphos (0-3thy1 S,S-diphenylphosphorothioate). However, the effect was not observed when edifenphos was applied prior to pendimethalin. There was no antidoting effect of indole acetic acid (IAA), gibberellic acid ($GA_3$) and kinetin used alone, but combinations of 3 ppmw IAA + either 3 or 5 ppmw $GA_3$ and 1 ppmw kinetin + 10 ppmw $GA_3$ reduced the phytotoxicity of pendimethalin.

• Journal of Plant Biotechnology
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• v.42 no.1
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• pp.34-42
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• 2015

This study was conducted to investigate the productivity of biomass and antioxidant compounds in Polygonum multiflorum by culturing explants in air-lift bioreactor containing Murashige and Skoog (MS) medium, by adding different concentrations of auxins [indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA)], sucrose, methyl jasmonate (MeJA), and salicylic acid (SA). Results of this study revealed that the explants culturing on the medium supplemented with $9.84{\mu}M$ IBA and 50 g/L sucrose were observed to have higher productivity of biomass and bioactive compound than other treatments used. Thus, we expect that these results will be helpful for large-scale production of biomass and antioxidant compounds from Polygonum multiflorum.