• The Plant Pathology Journal
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• v.30 no.3
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• pp.323-329
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• 2014

Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ) treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

• Analytical Science and Technology
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• v.30 no.1
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• pp.26-31
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• 2017

Background and purpose: This study was carried out to learn more about the potential prophylactic or antibacterial activity of the plant Acalypha indica against selective pathogenic bacteria. Experimental: The test organisms were Sarcina lutea IFO 3232, Bacillus subtilis IFO 3026, Pseudomonas denitrificans, Escherichia coli IFO 3007, Klebsiella pneumoniae ATTC 10031, Xanthomonas campestris IAM 1671, and Proteus vulgaris. Leaf, stem, and bud powder of Acalypha indica were dissolved in various solvents, and the extracts were tested for antimicrobial activity through the disc diffusion method. GC-MS profiling was performed to characterize active chemical compounds in the essential oil of Acalypha indica. Results: The ethanol extract showed the highest activity against all bacteria, while the petroleum ether extract yielded the highest zone of inhibition against Proteus vulgaris ($11.83{\pm}1.75mm$). The minimum inhibitory concentration (MIC) of the ethyl acetate extract against Bacillus subtilis was 16 µg/mL. Phytochemical screening by GC-MS revealed a total of 12 bioactive compounds. Conclusion: Extracts of Acalypha indica may be useful in formulating and synthesizing new antibacterial drugs.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.04a
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• pp.150-156
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• 2000

Oligotrophic bacteria isolated from forest soil showed a specific community consisting of various taxonomic groups compared with those in other soil or aquatic habitats. Based on the cell shape, the isolates were divided into four groups: regular rod, curved/spiral rod, irregular rod, and prosthecate bacteria. The cellular fatty acids 60 oligotrophic isolates were analyzed. The 30 fatty acids which were identified or characterized are classified. At the dendrogram based on cellular fatty acid composition, four clusters(I-IV) were separated at a euclidian distance of about 50. Cluster 3 and 4-a strains were containing Q-8, these strains are accommodated in the Proteobacteria gamma and beta subdivision. The chemotaxonomic profiles of the cluster 4-a strains showed good agreement with those of the genus Burkholderia. Cluster 3 was characterized by the presence of branched-chain fatty acids, iso-C15:0, iso-C17:1, and iso-C17:0 as the major components. These chemotaxonomy suggested the close relationship of the isolates with Xathomonas/Sterotrophomonas group. Based on the 16S rDNA sequence analysis, the two representative strains(MH256 and MA828) of cluster 3 showed the close relation to genera, Xathomonas/Sterotrophomonas, but were not included in these genera. These strains were even further away from core Xanthomonas, and clearly were seen to branch outside the cluster formed by the Sterotrophomonas maltophilia. MH256 and MA828 16S rDNA sequence was different enough to put new genus on a separate branch. The isolates with Q-10 were also studied. They are corresponded to the two large groups in Proteobacteria alpha subdivision. One was incorporated in the genus Bradyrhizobium cluster, which also includes Agromonas, a genus for oligotrophic bacteria. The strains of the other group showed high similarity to the genus Agrobacterium.

• Molecules and Cells
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• v.24 no.2
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• pp.232-239
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• 2007

$HrpN_{EP}$, from the gram-negative pathogen, Erwinia pyrifoliae, is a member of the harpin group of proteins, inducing pathogen resistance and hypersensitive cell death in plants. When the $hrpN_{EP}$ gene driven by the OsCc1 promoter was introduced into tobacco plants via Agrobacterium-mediated transformation, their resistance to the necrotrophic fungal pathogen, Botrytis cinerea, increased. Resistance to B. cinerea was correlated with enhanced induction of SA-dependent genes such as PR-1a, PR2, PR3 and Chia5, of JA-dependent genes such as PR-1b, and of genes related to ethylene production, such as NT-EFE26, NT-1A1C, DS321, NT-ACS1 and NT-ACS2. However the expression of NPR1, which is thought to be essential for multiple-resistance, did not increase. Since the pattern of expression of defense-related genes in $hrpN_{EP}$-expressing tobacco differed from that in plants expressing $hpaG_{Xoo}$ from Xanthomonas oryzae pv. Oryzae, these results suggest that different harpins can affect the expression of different defense-related genes, as well as resistance to different plant pathogens.

• 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.

• Korean journal of applied entomology
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• v.17 no.1 s.34
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• pp.37-40
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• 1978

The resistance to bacterial leaf blight of Conventional varieties (chodongi, Yongcheon etc.) cultivated from 1920 to 1956 in Korea were tested by means of 5 pathotypes of causal organism Xanthomonas oryzase (Uyeda et lshiyama) DOWSON. The results of this test are: 1. Among 74 varieties, 69 varieties including 'Chodongji, Yongcheon, Aedhal, Yongsang, Daegu, Mitdhari, pungok, etc' belong to the Kinmaze group that is highly susceptible to this disease. 2. 3 varieties: Heukbal, Doipnam, Whangphan belong to the Kogyoku group. 3. 2 varieties: Namgok, Gangbukdo, show unknown reaciton to differential varieties. 4. In 69 varieties belonging to the Kinmaze group $99.5\%$ of the plants were infected by bacterial group I. $99.6\%$ in bacterial group II. $100\%$ in group III, $99.7\%$ in group IV, and $99.8\%$ in group V. 5. In 3 varieties belong to Kyogyoku group, $1.7\%$ of the plants were infected in bacterial group I. $98.8\%$ in group II, $100\%$ in group III, IV and $1.4\%$ in group V.

• Plant Resources
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• v.7 no.3
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• pp.187-194
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• 2004

Sequence-tagged site (STS) markers tightly linked to the bacterial leaf blight (BLB) resistance genes, xa5, xa13 and Xa21, were used in this study. A survey was conducted to find polymorphisms between the resistant and susceptible germplasm in rice. 500 of Korean varieties and 100 of landraces were evaluated in this study. STS marker, RG207 was used to having xa5 resistance gene of rice germplasm. 27 varieties of Korean germplasm showed resistant for xa5 gene. The RG136 an xa-13 marker resulted in a single band of approximately 1kb in all the rice accessions studied. In order to detect polymorphism, digestion of the polymerase chain reaction (PCR) product was performed using a restriction enzyme Hinf Ⅰ. The resistant lines resulted in two bands 0.5kb on digestion with Hinf Ⅰ, while the same enzyme did not digest the PCR product of susceptible lines. No polymorphism was detected in Korean varieties and landraces, indicating that they probably do not contain xa13 gene. pTA248 an Xa-21 marker detected a band of 1kb in the resistant lines and bands of either 750bp or 700bp in the susceptible lines. Among germplasm tested, there are no varieties and landraces with Xa21 resistant gene. The results of the germplasm survey will be useful for the selection of parents in breeding programs aimed at transferring these bacterial blight resistance genes from one varietal background to another.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.703-712
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• 1998

Physicochemical factors, microbial population size and the properties of the bacterial isolates were estimated to find out the nature of soil ecosystem of Mt. Nam. Samples were obtained from the surface layer of soils on which specific plant community is developed. Average content of moisture and organic matter of the soils were 21.6% and 17.3%, respectively. These values were similar to those of developing forest soils, but were slightly lower than those of climax ecosystem such as Piagol in Mt. Chiri. Chiri. Content of phosphate was higher than those of other forest soils. The population size of soil bacteria ranged from 27.4 to 195.8 ${\times}\;10^5$ CFU/g. duy soil, and the size is somewhat dependent on the moisture and oranic matter content of soils. A large number of bacteria were able to decompose macromolecules such as starch, elastin and gelatin. Bacterial species composition of each soil was comparatively simple. Pseudomonas, Agrobacterium, Flavobacterium and Xanthomonas which are Gram-negative short rods were widely distributed in the forest soils. The endospore forming Bacillus species were also the main constituents of the soil microflroa. Actinomycetes were widely distributed in the forest soils, but the distribution pattern varied in each site. Most of the actinomycetes were also able to decompose organic macromolecules. The rate of resistant actinomycete strains to antibiotics and heavy metals were lower than those from cultivated soils, but higher than those from well-preserved forest soils. Antibiosis pattern of the actinomycete isolates was similiar to the resistance pattern. This means the forest soils of Mt. nam was somewhat interferred by artificial behabiour.

• The Korean Journal of Ecology
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• v.21 no.5_2
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• pp.575-583
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• 1998

Physicochemical factors, microbial population size and the properties of the bacterial isolates were assessed to find out the nature of soil ecosystem of Mt. Paektu. Samples were obtained from the surface layer of soils on which specific plant community is developed. Average content of moisture, organic matter and avaiable phosphate of the soils were 21.6%, 17.3% and 2.48mg/100g, respectively. These values were similar to those of developing forest soils, but were slightly lower than those of climax ecosystem such as Piagol in Mt. Chiri. The population size of soil bacteria ranged from 2.7 to $202.5{\times}10^5$ CFU/g.dry soil, and the size is somewhat dependent on the content of moisture and oranic matter of the forest soil. A large number of bacteria was able to decompose macromolecules such as starch, elastin and gelatin. While the distribution rate of resistant bacteria to antibiotics was high, that to toxic chemicals was low. This means that the competition between microorgani는 predominate over the interference with artificial behaviour such as spread of pesticides in the surveyed region. Bacterial species composition of each soil was comparatively simple. Pseudomonas, Agrobacterium, Flavobacterium and Xanthomonas which are Gram-negative short rods were widely distributed in the forest soils. The endospore forming Bacillus species were also main constituents of the soil microflroa. any one of the strains was not identified as Azospirillum or Micrococcus which are known to be one of major constituents of the forest soil. for the correct identification of isolates chemotaxonomic studies will be proceeded, and the strains are to be stored in the Type collection Center.

• Research in Plant Disease
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• v.21 no.2
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• pp.89-93
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• 2015

This study was carried out to develop the economic thresholds for the control of bacterial spot of red pepper. The correlation between diseased leaf rate and yield in field was Y=-0.724X+281.58, $R^2=0.78$, $r=-0.88^{**}$. The correlation between diseased leaf rate and yield loss in field was Y=0.813X+15.95, $R^2=0.78$, $r=0.88^*$.We found that control thresholds was below 30.3% diseased leaves rate per plant in field. The economic control thresholds for bacterial spot of red pepper was below 16.3%.