• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.4
• /
• pp.266-287
• /
• 2004

The non infecting, plant associated bacteria have attracted increased attention for stimulating plant growth and as environmental friendly plant protecting agents. Pink-pigmented facultatively methylotrophic bacteria (PPFMs), classified as Methylobacterium spp., are persistent colonizers of plant leaf surfaces. As the leaves of most or all plants harbor PPFMs that utilize leaf methanol as their sole source of carbon and energy, which is a specific attribute of the genus Methylobacterium. Although they are not well known, these bacteria are co-evolved, interacting partners in plant metabolism. This claim is supported, for example, by the following observations: (1) PPFMs are seed-transmitted, (2) PPFMs are frequently found in putatively axenic cell cultures, (3) Low numbers of seed-borne PPFMs correlate with low germinability, (4) Plants with reduced numbers of PPFM show elevated shoot/root ratios, (5) Foliar application of PPFMs to soybean during pod fill enhances seed set and yield, (6) Liverwort tissue in culture requires PPFM-produced vitamin B12 for growth, (7) treated plants to suppress or decrease disease incidence of sheath blight caused by Rhizoctonia solani in rice, and (8) the PPFM inoculation induced number of stomata, chlorophyll concentration and malic acid content, they led to increased photosynthetic activity. Methylobacterium spp. are bacterial symbionts of plants, shown previously to participate in plant metabolism by consuming plant waste products and producing metabolites useful to the plant. There are reports that inform about the beneficial interactions between this group of bacteria and plants. Screening of such kind of bacteria having immense plant growth promoting activities like nitrogen fixation, phytohormone production, alleviating water stress to the plants can be successfully isolated and characterized and integration of such kind of organism in crop production will lead to increased productivity.

• Horticultural Science & Technology
• /
• v.32 no.5
• /
• pp.702-709
• /
• 2014

Luffa cylindrica Roem (sponge gourd) belongs to the Cucurbitaceae family and has been cultivated as an ornamental plant in Korea. Recently, its cultivation area has been increased with an increase in demand for it as an ingredient in cosmetics, herbal medicines, and health supplements. We analyzed inorganic components of sap collected from land race sponge gourds. We also measured antioxidant enzyme activities and antimicrobial activities of the plant, seed, and sap to examine functional properties of sponge gourd. The sap of the sponge gourd contained high levels of K, Ca, P, and Mg, with the most abundant mineral in the sap being K ($470mg{\cdot}L^{-1}$). The amounts of Ca and Mg were 2 and 1.7 times more than those found in cucumber (Cucumis sativus), respectively. Ascorbate peroxidase was more active than catalase and superoxide dismutase in various plant parts of sponge gourd. Antioxidant activities were much lower in stems than in other plant parts such as leaves, roots, flowers, fruits, seeds, and sap. In addition, sap showed a very low level of antimicrobial activity against two food-borne pathogens, Vibrio parahaemdyticus and Propionibacterium acne, and none against the other eight tested food-borne pathogens. Antimicrobial activities against Candida albicans and Malassezia furfur, which causes dermatitis, appeared to be higher in sap than in other parts of sponge gourd plants. Overall, the antimicrobial activity against Malassezia furfur appeared to be higher than against Candida albicans.

• Korean journal of applied entomology
• /
• v.57 no.4
• /
• pp.415-423
• /
• 2018

Aphid is a typical vector that transfers various kinds of viruses to potatoes. Therefore, it is very important to control aphids moving into potato fields. We investigated the seasonal movement pattern of aphids and its virus transmission rates mainly in the three seed potato production regions at highland in Gangwon-do, Korea. In addition, we identified the aphid species with over-wintering eggs collected from barks or twigs of total 57 tree species around potato fields in winter season. The peak time of summer and winter migration of aphid was at the mid-June and the early October, respectively. A 2.8% of total aphid trapped in yellow water-pan trap was turned out PLRV-borne, and the virus transmission rate was 15.4% by Myzus persicae and 9.1% by Macrosiphum euphorbiae. PLRV-borne aphids started to flow in from the late May, and virus transmission rate of aphid trapped in mid-June was the highest with 10.4%. Totally 14 species of aphid eggs wintered in the 17 species of trees including Acer pictum subsp. mono and Acer pseudosieboldianum at the 11 sites. In particular, because it is not certain that Betula platyphylla var. japonica and Yamatocallis hirayamae do transmit potato virus, but they over-wintered in host plants distributed over a wide area, further research on transmission ability is necessary.

• Research in Plant Disease
• /
• v.17 no.3
• /
• pp.376-380
• /
• 2011

The bacterial speck of tomato caused by Pseudomonas syringae pv. tomato leads to serious economic losses especially on fruits of susceptible genotype. Thus, Pseudomonas syringae pv. tomato is a plant quarantine bacterium in many countries including Korea. In this study, we developed specific PCR assays for detection of the bacterium from tomato seeds. A specific primer set is designed from the hrpZ gene for specific detection of Pseudomonas syringae pv. tomato. A 501 bp PCR product corresponding to hrpZ gene was amplified only form Pseudomonas syringae pv. tomato strains, but no PCR product was amplified from other tomato bacterial pathogens, such as Pseudomonas syringae pv. glycinea, P. syringae pv. maculicola, P. syringae pv. atropurpurea, P. syringae pv. morsprunorum, and from other P. syringae pathovar strains. The nested-PCR primer set corresponding to an internal fragment of the 501 bp sequence (hrpZ) gine was used to specific detection of Pseudomonas syringae pv. tomato in tomato seed. A 119 bp PCR product using nested PCR primer was highly specific and sensitive to detect low level of Pseudomonas syrigae pv. tomato in tomato seeds. We believe that the PCR assays developed in this study is very useful to detect Pseudomonas syringae pv. tomato from the tomato seeds.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.15 no.1
• /
• pp.1-12
• /
• 1995

This study was to investigate an effective biological control of forage diseases and provide a basic data and a model in improving variety of antagonistic bacteria, with growth promoting effect on forage, through cell fusion. The results obtained were summarized as follows; 1. The antagonistic himbacterium against soil-borne phathogenic fungi Fusarium oxysporum and Rhizoctonia solani was isolated from continuous cropping himsphere soil of forage, and its biological and physiological characteristics were investigated. This bacterium was identified as Bacillus subrilis and named BS 101. Another strain for cell fusion was Bacillus thur ingiensis ssp. kurstaki HD-I(BT 37669) with insecticidal crystal. 2. The auxotropic mutants of BS 101 and BT 37669 were derived after mutagenesis using N-methyl-N'nitro- Nitrosoguanidine(NTG) to give amino acid requirement marker. n e s e auxotropic mutants of BS 101 and BT 37669 were named BS 1013(his-) and BT 69(asp-), respectively. 3. The best protoplast requirement was obtained using DM 3 medium, containing 5% casamino acid, 1 M $MgCI_2$ and 2% bovine semm albumin, to give Fusant 3, 7 and 8. BT toxin gene was not identified with fusants by Southern blotting. However, SDS-PAGE analysis of strains showed various protein patterns among fusants. 4. From the dark culture experiment, growth of forage in inoculated soil with antagonistic bacteria was delayed than that of non-inoculated soil with antagonistic bacteria in each continuous cropping soil and in each sterilized soil. On the other hand, growth duration of forage was different between continuous cropping soil and sterilized soil. 5. Seed germination of Alfalfa, Italian ryegrass and Orchardgrass were significantly improved by inoculation of antagonistic bacteria(p< 0.05).

• The Korean Journal of Mycology
• /
• v.33 no.2
• /
• pp.81-85
• /
• 2005

A total of 81 isolates of Penicillium were isolated from postharvest seeds of barely, Job's-tears, maize, sorghum and rice from 1997 to 2003. Based on the morphological characteristics, they were identified as P. chrysogenum, P. citrinum, P. cyclopium, P. oxalicum, P. polonicum, P. purpurogenum and P. viridicatum. P. chrysogenum was detected from Job's-tears, rice and sorghum seeds, P. citrinum from maize seeds, P. cyclopium from sorghum seeds, P. oxalicum from barely, maize, sorghum and rice seeds, P. purpurgenum from maize, rice, sorghum seeds, P. viridicatum from Job's-tears, maize and rice seeds, P. polonicum from Job's-tears, maize, rice and sorghum seeds. Among these species, P. cyclopium, P. polonicum and P. purpurogenum were first reported in Korea. Especially, about 50% of the Penicillium isolates detected from the seeds were P. polonicum. Identification of the Penicillium species using morphological characteristics was difficult especially for the species belonging to the subgenus Penicillium such as P. polonicum.

• Korean journal of applied entomology
• /
• v.20 no.4 s.49
• /
• pp.191-195
• /
• 1981

Cucurbits including pumpkin (Cucurbita pepo), gourd (Lagenariaa siceraria), cucumber (Cucumis sativus), melon(Cucumis melo) and watermelon(Cucurbita anguria) were diseased with mosaic symptoms. The causal virus was identified as watermelon mosaic virus(WMV). The WMV was transmitted by Myzus persicae Sulzer, and no seed borne virus was found. The virus caused large local lesions on the inoculated leaves of the Chenopodium amaranticolor and mosaic symptom on the upper leaves of Cucumis melo, Cucumis sativus, Lagenaria siceraria, Cucurbita anguria and Cucurbita pepo. There were no symptoms on the inoculated leaves of the Nicotiana tabacum var. Bright yellow, Nicotiana glutinosa, Vigna unguiculata. Petunia hybrida and Datura stramonium. Thermal inactivation point was $55\~65^{\circ}C$, dilution end point was $10^{-4}\;10^{-5}$ and longevity in vitro of the virus was $7\~8$ days. The virus showed positive reaction against watermelon mosaic virus antiserum in microprecipitin tests. The virus particles were flexuous rods in size of 750 nm.

• Journal of Bio-Environment Control
• /
• v.12 no.4
• /
• pp.180-183
• /
• 2003

P. wasabiae was isolated from discolored seeds of wasabi(Wasabia japonical Mtsum.) and inoculated to fresh seeds, then the effect of fungicides on suppression of diseases were determined. Emergence rate of wasabi seeds where suppressed to 52.5% by the inoculation and it reached up to 92.7% by dipping treatment of inoculated seeds ito benomyl solution. The incidence rate of black leg disease and damping off were 32.0 and 22.0%, respectively, in control treatment that sown in the soil inoculated with P. wasabiae. But dipping treatment of inoculated seeds into benomyl solution resulted in 12.0% and 10.7% in incidence rate of those two diseases, respectively.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.2
• /
• pp.243-249
• /
• 2001

This study was investigated to determine the antimicrobial effect of the ethanol extract of Quercus mongolica leaf on microbial growth. The ethanol extract at the concentration of $250\;\mu\textrm{g}/mL\;and\;500\;\mu\textrm{g}/mL$ inhibited the growth of gram positive and gram negative food-borne disease bacteria for 40 hours in tryptic soy broth, respectively. Antimicrobial activity of the ethanol extract from Quercus mongolica leaf was not affected by pH and heat treatment. The comparision between ethanol extract and commercially available preservatives on antimicrobial activity in food system was conducted. When the 0.1% ethanol extract of Quercus mongolica leaf was added to pine needle drink and carrot juice, antimicrobial activity was similar to those of containing 0.05% benzoic acid and 0.5% grapefruit seed extract. Also addition of 2~3% ethanol extract to the soybean paste inhibited the microbial growth up to 7 week, comparable to the inhibition of 2% ethanol. Thus, this results indicate that the ethanol extract of Quercus mongolica leaf may be useful as natural antimicrobial agents.

• The Plant Pathology Journal
• /
• v.20 no.1
• /
• pp.63-66
• /
• 2004

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herbs in Korea. However, yield losses reached up to 30-60％ due to various diseases during 3 or 5 years of ginseng cultivation in the country. Therefore, successful production of ginseng roots depends primarily on the control of diseases. The objective of this study was to select potential biocontrol agents from rhizobacteria isolated from various plant internal root tissues for the control of multiple ginseng diseases as an alternative to fungicides. Among 106 Bacillus strains, two promising biocontrol agents, Bacillus pumilus strain B1141 and Paenibacillus lentimobus strain B1146, were selected by screening against root rot of ginseng caused by Cylindrocarpon destructans in a greenhouse. Pre-inoculation of selected isolates to seed or l-year-old root of ginseng resulted in stimulation of shoot and/or root growth of seedlings, and successfully controlled root rot caused by C. destructans (P<0.05). Furthermore, drenching of cell suspension of the selected isolates on seedling-growing pots reduced the incidence of Phytophthora blight after the seedlings were challenged with zoospores of Phytophthora cactorum (P<0.05). P. lentimorbus strain B1146 showed antifungal activity against various soil-borne pathogens in vitro, while B. pumilus strain B1141 did not show any. Results of this study suggest that some rhizobacteria can induce resistance against various plant diseases on ginseng.