• Applied Biological Chemistry
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• v.41 no.1
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• pp.104-109
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• 1998

Methanol extracts from 84 Indian plant samples (50 species in 31 families) and 27 African plant samples (20 species in 12 families) in vitro were tested for their growth-inhibitory activities against Bifidobacterium bifidum, Bifidobacterium longum, Lactobacillus acidophilus, Clostridium perfringens, and Escherichia coli, using a paper disc agar diffusion method under $O_2-free$ conditions. The responses varied with bacterial strain, plant species and plant part. Extracts from Cymbopogon citratus whole plants, Ocimum basilicum whole plant, Madhuca indica flowers, and Aegle marmelos leaves among Indian plant samples moderately or strongly inhibited the growth of Cl, perfringens whereas moderate growth-inhibitory activity against E. coli was obtained from extract of Indian O. basilicum whole plants. These plant extracts did not affect the growth of the lactic acid forming bacteria tested. These results may be an indication of at least one of the pharmacological actions of these tropical plants.

• Research in Plant Disease
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• v.22 no.4
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• pp.284-288
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• 2016

A plant growth promoting rhizobacterium, Bacillus vallismortis BS07M, was formulated as a clay pellet (CP) to evaluate its pepper growth promotion and induced resistance against various diseases under field and storage conditions. Peppers were grown in 50-hole tray containing potting mixture with CP in seedling raising stage, and then it was transplanted into a field. After transplanting, pepper plants treated with CP in seedling raising stage increased shoot growth and reduced disease severity caused by Phytophthora capsici in detached pepper leaves compared to untreated control. Moreover, treatment with CP in seedling raising stage increased fruit weight per plant; after harvesting, pepper fruits shown reduced diameter of lesions by Colletotrichum acutatum, and occurrance of soft rot in storage condition. These results indicated that CP could affect plant growth and induced resistance in pepper plants under field condition, and maintenance of fruit during storage.

• Proceedings of the Plant Resources Society of Korea Conference
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• v.18 no.1
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• pp.110-111
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• 2005

• The Plant Pathology Journal
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• v.27 no.4
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• pp.301-309
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• 2011

The filamentous fungus Fusarium graminearum is an important cereal pathogen. Although quantitative realtime PCR (qRT-PCR) is commonly used to analyze the expression of important fungal genes, no detailed validation of reference genes for the normalization of qRT-PCR data has been performed in this fungus. Here, we evaluated 15 candidate genes as references, including those previously described as housekeeping genes and those selected from the whole transcriptome sequencing data. By a combination of three statistical algorithms (BestKeeper, geNorm, and NormFinder), the variation in the expression of these genes was assessed under different culture conditions that favored mycelial growth, sexual development, and trichothecene mycotoxin production. When favoring mycelial growth, GzFLO and GzUBH expression were most stable in complete medium. Both EF1A and GzRPS16 expression were relatively stable under all conditions on carrot agar, including mycelial growth and the subsequent perithecial induction stage. These two genes were also most stable during trichothecene production. For the combined data set, GzUBH and EF1A were selected as the most stable. Thus, these genes are suitable reference genes for accurate normalization of qRT-PCR data for gene expression analyses of F. graminearum and other related fungi.

• Journal of Life Science
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• v.29 no.11
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• pp.1281-1293
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• 2019

The rhizosphere is the active zone where plant roots communicate with the soil microbiome, each responding to the other's signals. The soil microbiome within the rhizosphere that is beneficial to plant growth and productivity is known as plant growth-promoting rhizobacteria (PGPR). PGPR take part in many pivotal plant processes, including plant growth, development, immunity, and productivity, by influencing acquisition and utilization of nutrient molecules, regulation of phytohormone biosynthesis, signaling, and response, and resistance to biotic- and abiotic-stresses. PGPR also produce secondary compounds and volatile organic compounds (VOCs) that elicit plant growth. Moreover, plant roots exude attractants that cause PGPR to aggregate in the rhizosphere zone for colonization, improving soil properties and protecting plants against pathogenic factors. The interactions between PGPR and plant roots in rhizosphere are essential and interdependent. Many studies have reported that PGPR function in multiple ways under the same or diverse conditions, directly and indirectly. This review focuses on the roles and strategies of PGPR in enhancing nutrient acquisition by nutrient fixation/solubilization/mineralization, inducing plant growth regulators/phytohormones, and promoting growth and development of root and shoot by affecting cell division, elongation, and differentiation. We also summarize the current knowledge of the effects of PGPR and the soil microbiota on plants.

• Korean Journal of Plant Resources
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• v.32 no.3
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• pp.228-236
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• 2019

This study is conducted to investigate the effects of growth characteristics (GC) and DPPH radical scavenging activity (DRSA) of the heading lettuce 'Fidel' depending on four concentrations of activated mineral groups (AMG: 1.6% active minerals and 0.03% CaO) added to basic nutrient solutions (diluted by 0, 0.05, 0.1, and 0.2%) and on four different light-emitting diodes (LED; B:R:W ratio = 0:1:12, 0:1:9, 0:5:5, and 2:3:5). Both 0.1 and 0.2% AMG showed better GC of lettuce in plant width, plant length, leaf width, leaf length, and the number of leaves than those of other AMG, while leaf thickness and chlorophyll value did not show significant difference among all AMG. Moreover, 0.1 and 0.2% AMG showed heavier shoot fresh weights than those of other AMG. As for the combinations of AMG and LED, B0:R5:W5 showed the best lettuce GC regardless of AMG compared to other AMG and LED combinations. As shown in the above results of LED, although there was a difference in lettuce growth by LED, the differences of lettuce growth by AMG were statistically significant. The DRSA was the highest at 82.8% in B2:R3:W5, followed by B0:R5:W5 at 77.8%. LED showed differences but AMG did not affect DRSA. Therefore, the optimal conditions in plant factory for GC and DRSA of the lettuce were 0.1% AMG and B0:R5:W5.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.1
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• pp.77-88
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• 2011

This study was carried out to investigate the effects of soil depth and planting density on the growth of lettuce, crown daisy, and strawberry on a rooftop condition using artificial soil as a growth media. The vegetable crops showed better growth for plant height (cm), plant width (cm), plant fresh weight (g), and Fo, Fm and Fv/m on 20cm depth soil than 10cm depth soil except strawberry. Planting density of $16/m^2$ and $64/m^2$ did not show significant differences on the growth of the crops. Soil moisture content and EC were low for 10cm depth soil in lettuce plots, whereas there was no significant differences on soil moisture and EC between two soil depth in strawberry plots. Hunter's L, a, and b values showed the leaf color of lettuce dark green on 20cm depth soil and reddish on 10cm depth soil. Results showed that soil depth suitable for crop growth on rooftop conditions was 20cm rather than 10cm. Growth response of the crops showed no significant difference between $16/m^2$ and $64/m^2$, indicating that planting density of 64 $plants/m^2$ could be practiced on rooftop conditions. Lettuce growth rapidly changed in control treatment in which leaves were not pinched out, while slowly changed in plants which leaves were periodically pinched out. In the case of control plot, it was impossible to harvest because withering of lower leaves after blossom on June 22. The plant of crown daisy in which pinching was not conducted, blossomed on June 7, and the plants were removed since its aesthetical value was lost. Strawberry seemed to be a suitable vegetable crop for rooftop conditions based on its high covering rate and extended growth period until late October. The soil depth 20cm and planting density 64 $plants/m^2$ were suitable for vegetable crops on green roof system using artificial soil.

• Journal of the Korean Society of Tobacco Science
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• v.30 no.1
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• pp.1-7
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• 2008

Bacterial wilt caused by Ralstonia solanacearum has become a severe problem on tobacco in Korea. No effective single control measure is available at present time. One of the most potential way for controlling the bacterial wilt on tobacco is growing tobacco cultivars resistant to the bacterial wilt. In this study, optimal conditions for screening tobacco cultivars resistant to the bacterial wilt were examined to provide reproducible and efficient methods in growth chamber testing and field experiments for evaluating plant disease resistance. For this, already-known inoculation methods, inoculum densities, and incubation temperature, and plant growth stages at the time of inoculation were compared using tobacco cultivars resistant (Nicotiana tabacum cv, NC95), moderately resistant (N. tabacum cv. SPG70), and susceptible (N. tabacum BY4) to the bacterial disease. It was determined that root-dipping of tobacco seedlings at six true leaf stage into the bacterial suspension with inoculum level of $10^8$ colony-forming units (CFU)/ml for 20 min before transplanting was simple and most efficient in testing for resistance to the bacterial wilt of tobacco caused by R. solanacearum, for which disease incidences and severities were examined at 2 weeks of plant growth after inoculation at $20{\sim}25^{\circ}C$ in a growth chamber. These experimental conditions could discriminate one tobacco cultivar from the others by disease severity better than any other experimental conditions. In field testing, the optimum time for examining the disease occurrence was late June through early July. These results can be applied to establishing a technical manual for the screening of resistant tobacco cultivars against the bacterial wilt caused by R. solanacearum.

• Korean Journal of Medicinal Crop Science
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• v.23 no.3
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• pp.214-222
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• 2015

This study was conducted to evaluate the growth conditions and vegetation of Peucedanum japonicum habitat in uninhabited islands of Incheon Korea. The emergence area of Peucedanum japonicum was 4.9 m distance in coastline, and altitude and slope was 7.4m and 47.5%. Soil pH, organic matter and $P_2O_5$ of habitat were 7.1, 8.3% and 29.0 mg/kg, and contents of K, Ca, Mg and Na were 0.66, 4.9, 3.4 and $1.13cmol^+/kg$, respectively. Growth plants with Peucedanum japonicum were total 55 taxa, and Gakeuldo in uninhabited islands was the most as 25 taxa. In growth plants with Peucedanum japonicum, plants of over 25% frequence per plot were Miscanthus sinensis, Dendranthema boreale, Lilium lancifolium, Hemerocallis middendorffii, Elymus dahuricus, Cirsium japonicum var. maackii, Asparagus schoberioides, Gypsophila oldhamiana, Cocculus trilobus, Silene aprica var. oldhamiana, Artemisia capillaris, Crepidiastrum denticulatum and Sedum oryzifolium. The vegetation of Peucedanum japonicum habitat was classified into Aster spathulifolius community, Miscanthus sinensis community, Dendranthema boreale community, Setaria viridis var. pachystachys community, Cirsium japonicum var. maackii community and Hemerocallis middendorffii community. According to general condition of habitat, suitable growing areas was determined to slightly acidic from mild alkaline soils.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1095-1100
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• 2008

The role of exopolysaccharides (EPSs) from a plant growth-promoting rhizobacterium, Burkholderia gladioli IN26, on elicitation of induced systemic resistance was investigated. A purified EPS induced expression of PR-1a::GUS on tobacco and elicited induced resistance against Colletotrichum orbiculare on cucumber. The maximum level of disease protection was noted when seeds were soaked in 200 ppm of the EPS. Our results indicate that EPS from specific rhizobacteria can elicit induced resistance and suggest that bacterial EPS might be a useful elicitor of resistance under field conditions.