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

• Mycobiology
• /
• v.33 no.3
• /
• pp.131-136
• /
• 2005

Infection structures were observed at the penetration sites on the leaves of cucumber plants inoculated with Colletotrichum orbiculare using a fluorescence microscope. The cucumber plants were previously drenched with suspension of bacterial strains Pseudomonas putida or Micrococcus luteus. The plants pre-inoculated with both bacterial strains were resistant against anthracnose after inoculation with C. orbiculare. To investigate the resistance mechanism by both bacterial strains, the surface of infected leaves was observed at the different time after challenge inoculation. At 3 days after inoculation there were no differences in the germination and appressorium formation of conidia of C. orbiculare as well as in the callose formation of the plants between both bacteria pre-inoculated and non-treated. At 5 days, the germination and appressorium formation of the fungal conidia were, however, significantly decreased on the leaves of plants pre-inoculated with M. luteus at the concentration with $1.0{\times}10^7\;cfu/ml$. Furthermore, callose formation of plants cells at the penetration sites was apparently increased. In contrast, there were no defense reactions of the plants at the concentration with $1.0{\times}10^6\;cfu/ml$ of M. luteus. Similarly, inoculation P. putida caused no plant resistance at the low concentration, whereas increase of callose formation was observed at the higher concentration. The results of this study suggest that the resistant mechanisms might be differently expressed by the concentration of pre-treatment with bacterial suspension.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.20 no.1
• /
• pp.8-13
• /
• 2016

The purpose of the pyro-shock compliant joint is to isolated vibration using the compliant material in order to prevent the shock generated by pyro propulsion at the electronics equipment. The performance of the pyro-shock compliant joint can be determined by measuring bending natural frequency and transmissibility. In this study, we established the design requirements based on bending natural frequency and transmissibility results of the reference model. We developed a compliant material with sufficient shock compliant properties and a pyro-shock compliant joint for the new rocket. This results can be used to develop a pyro-shock compliant joint for any rocket using the compliant material and performance measurement.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.138-138
• /
• 2017

Agriculture is the most primitive civilized Activities of mankind but also the propellant of civilization development. Because it is the most basic material goods source of mankind. Among these materials rice is one of the most important part of these, we call them the substance of survival. From the beginning of the agricultural activities to the present we have experienced three industrial revolutions and are experiencing the Fourth Industrial Revolution. With the development of science and technology makes the efficiency of agricultural production is higher and higher, but compared with the original we are facing the same problem: natural disasters; pests and diseases; now also face the depletion of resources, environmental degradation and other issues. Therefore, improve and cultivate new crop varieties to make it better resistance and more production for better develop modern agriculture. It's very helpful for human social development. And also it is the responsibility and task of modern molecular breeding. In this study, I used bacterial leaf blight to find a better resistance gene to improve the resistance of rice. Frist Cultivate k3 of bacterial leaf blight, than inoculation by leaf clipping method (Kauffman,1973) in CNDH and SNDH population at 40days after rice transplanting. Check the lesion length by inoculation plants at 14days after inoculation, and record data for QTL analysis program. Than I get 4 intervals in 3 different chromosomal regions. I found these defense genes in the 4 intervals. So I used NCBI Justbio, Rapdb, etc. to finding these genes in physical map, than design primer for map base cloning. At last these defense genes will be employed in further research for introduction of the gene to the parental plant and rice breeding for solving food crisis.

• The Plant Pathology Journal
• /
• v.32 no.4
• /
• pp.311-320
• /
• 2016

Xanthomonas axonopodis pv. glycines (Xag) is a necrotrophic bacterial pathogen of the soybean that causes bacterial pustules and is a nonhost pathogen of the chili pepper. In the current study, chili pepper fruit wound inoculated in planta with Xag 8ra formed necrotic lesions on the fruit surface and induced several structural and chemical barriers systemically in the fruit tissue. The initial defense response included programmed cell death of necrotizing and necrotized cells, which was characterized by nuclear DNA cleavage, as detected by TUNEL-confocal laser scanning microscopy (CLSM), and phosphatidylserine exposure on cell walls distal to the infection site, as detected by Annexin V FLUOS-CLSM. These two responses may facilitate cell killing and enhance transportation of cell wall materials used for cell wall thickening, respectively. The cells beneath the necrotic tissue were enlarged and divided to form periclinal cell walls, resulting in extensive formation of several parallel boundary layers at the later stages of infection, accompanying the deposition of wall fortification materials for strengthening structural defenses. These results suggest that nonhost resistance of chili pepper fruit against the nonhost necrotrophic pathogen Xag 8ra is activated systematically from the initial infection until termination of the infection cycle, resulting in complete inhibition of bacterial pathogenesis by utilizing organspecific in situ physiological events governed by the expression of genes in the plant fruit organ.

• Journal of Life Science
• /
• v.21 no.9
• /
• pp.1295-1300
• /
• 2011

The AtPGR gene is induced by pathogen infection, jasmonic acid and salicylic acid treatment and may therefore play a role in plant defense responses. Arabidopsis thaliana Plasma membrane Glucose-responsive Regulator (AtPGR) was previously isolated from Arabidopsis, which confers glucose insensitivity on plants. To study its biological functions directly, we have characterized both loss-of-function RNAi mutant and gain-of-function transgenic overexpression plants for AtPGR in Arabidopsis. The AtPGR-overexpressing plants displayed enhanced resistance to a virulent strain of the bacterial pathogen Pseudomonas syringae as measured by a significant decrease in both bacterial growth and symptom development as compared to those in wild-type and RNAi plants. The enhanced resistance in the gain-of-function transgenic plants was associated with increased induction of SA-regulated PDF1.2 and JA-regulated PR1 by the bacterial pathogen. Thus, pathogen-induced AtPGR plays a positive role in defense responses to P. syringae.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.7
• /
• pp.686-696
• /
• 2011

To deal with pathogens, plants have evolved sophisticated mechanisms including constitutive and induced defense mechanisms. Phytohormones play important roles in plant growth and development, as well as in the systemic response induced by beneficial and pathogen microorganisms. In this work, we identified an Aspergillus ustus isolate that promotes growth and induces developmental changes in Solanum tuberosum and Arabidopsis thaliana. A. ustus inoculation on A. thaliana and S. tuberosum roots induced an increase in shoot and root growth, and lateral root and root hair numbers. Assays performed on Arabidopsis lines to measure reporter gene expression of auxin-induced/ repressed or cell cycle controlled genes (DR5 and CycB1, respectively) showed enhanced GUS activity, when compared with mock-inoculated seedlings. To determine the contribution of phytohormone signaling pathways in the effect elicited by A. ustus, we evaluated the response of a collection of hormone mutants of Arabidopsis defective in auxin, ethylene, cytokinin, or abscisic acid signaling to the inoculation with this fungus. All mutant lines inoculated with A. ustus showed increased biomass production, suggesting that these genes are not required to respond to this fungus. Moreover, we demonstrated that A. ustus synthesizes auxins and gibberellins in liquid cultures. In addition, A. ustus induced systemic resistance against the necrotrophic fungus Botrytis cinerea and the hemibiotrophic bacterium Pseudomonas syringae DC3000, probably through the induction of the expression of salicylic acid, jasmonic acid/ethylene, and camalexin defense-related genes in Arabidopsis.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.86-86
• /
• 2003

Phytophthora capsici is a pathogen on several economically important crops including pepper. In pepper growing areas in Korea, Phytophthora blight caused by p. capsici has been considered as the most serious problem in pepper production. The Oomycete attacks the roots, stems, leaves and fruits of the plant. To understand the molecular mechanisms involved in the disease development, the genes expressed doting pepper p. capsici interaction were explored by analyzing expressed sequence tags (ESTs). A complementary DNA (cDNA) library was constructed from total RNA extracted from pepper leaves challenged with p. capsici for 3 days resulting in early stage of symptom development. The comprehensive analysis on the single pass sequencing of over 4000 randomly selected cDNA clones with contig assembly, unique gene extraction, sequence comparison, and functional categorizing will be presented with an emphasis on the genes involved in plant defense and pathogenicity during disease development of the pepper Phytophthora blight.

• The Plant Pathology Journal
• /
• v.24 no.3
• /
• pp.283-288
• /
• 2008

Plant leaf surface is an important niche for diverse epiphytic microbes, including bacteria and fungi. Plant leaf surface plays a critical frontline defense against pathogen infections. The objective of our study was to evaluate the effectiveness of a starch-based super-absorbent polymer(SAP) combination, which enhances water potential and nutrient availability to plant leaves. We evaluated the effect of SAP on the maintenance of bacterial populations. In order to monitor bacterial populations in situ, a SAP mixture containing Pseudomonas syringae pv. tabaci that expressed recombinant green fluorescent protein(GFPuv) was spray-challenged onto whole leaves of Nicotiana benthamiana. The SAP combination treatment enhanced bacterial robustness, as indicated by disease severity and incidence. Unexpectedly, bacterial numbers were not significantly different between leaves treated with the SAP combination and those treated with water alone. Furthermore, young leaves treated with the SAP combination had more severe symptoms and a greater number of bacterial spots caused by primary and secondary infections compared to young leaves treated with the water control. In contrast, bacterial cell numbers did not statistically differ between the two groups, which indicated that measurement of viable GFP-based bacterial spots may provide a more sensitive methodology for assessing virulence of bacterial pathogens than methods that require dilution plating following maceration of bacterial-inoculated leaf tissue. Our study suggests that the SAP combination successfully increased bacterial aggressiveness, which could either be used to promote the ability of biological agents to control weedy plants or increase the robustness of saprophytic epiphytes against competition from potentially harmful microbes.

• Journal of Plant Biotechnology
• /
• v.37 no.1
• /
• pp.1-11
• /
• 2010

Floral scent emitted from many plants is the key factor for pollinator attraction and defense for survival in nature and is important industrial materials for perfumery as well. It is a complex mixture of various organic molecules with a high volatility or a high vapor pressure. In general, floral scents are divided into three categories, aliphatics, terpenoids, and phenylpropanoids/benzenoids, based on its origin. About 1,700 scent compounds have been identified and their biochemistry and molecular biology also have elucidated their biosynthesis from various flowering plants during the last ten years. In addition to improvement of vase life, flower color and shape, and/or disease resistance, floral scent is coming up to the major breeding target for improvement of marketability. Therefore, metabolic engineering can be an important tool in near future and may be able to facilitate the breeding program for novel cultivar selection and improvement of marketability of floricultural crops.