• Journal of agriculture & life science
• /
• v.46 no.3
• /
• pp.37-45
• /
• 2012

To select bacterial strains with antifungal activity against an anthracnose fungal disease causing damage severely on hot pepper, previous isolates obtained from plant root samples were screened. Among 457 isolates, IA70-5 isolate was finally selected and identified as Streptomyces padanus based on 16S rDNA sequence analysis. Strain IA70-5 is non-pigmenteous, non-mobile, and filamentous. S. padanus IA70-5 inhibited effectively the mycelium growth, spore germination, and appressorium formation of Colletotrichum acutatum in vitro. The results of this study demonstrated that IA70-5 strain, especially applied on fruit of hot pepper, decreased disease incidence 90% for pre-inoculation before pathogen treatment. Taken together, S. padanus IA70-5 strain is a promising biological control agent to control of a major fungal pepper disease, anthracnose.

• The Plant Pathology Journal
• /
• v.38 no.6
• /
• pp.593-602
• /
• 2022

Anthracnose, caused by the ascomycete fungus Colletotrichum scovillei, is a destructive disease in pepper. The fungus germinates and develops an infection structure called an appressorium on the plant surface. Several signaling cascades, including cAMP-mediated signaling and mitogen-activated protein kinase (MAPK) cascades, are involved in fungal development and pathogenicity in plant pathogenic fungi, but this has not been well studied in the fruit-infecting fungus C. scovillei. Ste50 is an adaptor protein interacting with multiple upstream components to activate the MAPK cascades. Here, we characterized the CsSTE50 gene of C. scovillei, a homolog of Magnaporthe oryzae MST50 that functions in MAPK cascades, by gene knockout. The knockout mutant ΔCsste50 had pleiotropic phenotypes in development and pathogenicity. Compared with the wild-type, the mutants grew faster and produced more conidia on regular agar but were more sensitive to osmotic stress. On artificial and plant surfaces, the conidia of the mutant showed significantly reduced germination and failed to form appressoria. The mutant was completely non-pathogenic on pepper fruits with or without wounds, indicating that pre-penetration and invasive growth were both defective in the mutant. Our results show that the adaptor protein CsSTE50 plays a role in vegetative growth, conidiation, germination, appressorium formation, and pathogenicity in C. scovillei.

• Horticultural Science & Technology
• /
• v.34 no.3
• /
• pp.355-362
• /
• 2016

This study was carried out to investigate the effects of rain-shelter types on growth, and fruit quality of red pepper (Capsicum annuum, 'Kemmaru') cultured in paddy. Applied rain-shelter types were outfield (control), simple rain-shelter plastic house with 2 rows (2R), simple rain-shelter plastic house with 4 rows (4R), and perfect plastic house (House). The plant height was the highest in Houses treatment. There was no difference in leaf length and width among the rain-shelter treatments. The fresh and dry weight of red pepper was high in order of House > 4R > 2R > Control. The ASTA value is irregular tendency among the treatments. Hunter's color value 'a' and 'b' was not different from among the treatments. Phytophthora blight, powdery mildew, bacterial spot were not occurred in all of treatments, and Anthracnose was only occurred in control. Mite, Microcephalothrips abdominalis, and Bemisia tabaci were not occurred in all of treatments, and aphid, Helicoverpa assulta, and virus were occurred all of treatments as same degree. Our results will provide rain-shelter cultivation of red pepper can be increase dry yield and decrease disease and insects.

• The Korean Journal of Pesticide Science
• /
• v.21 no.1
• /
• pp.26-32
• /
• 2017

Antimicrobial activity of 6 phosphate compounds as $H_3PO_3$, $H_3PO_4$, $K_3PO_4$, $K_2HPO_4$, $KH_2PO_4$ and $NH_4H_2PO_4$ against Phytophthora capsici JHAW 1-2 and Colletotrichum acutatum JC24 was investigated in this study. Inhibitory effect on zoospore release, zoosporangia germination and zoospore germination was superior than mycelial growth. Among 6 compounds, $H_3PO_3$ and $H_3PO_4$ showed the best antimicrobial activity against P. capsici JHAW 1-2. Diseases controlling activity of the phosphate compounds tested on seedling and fruit of pepper against Phytophthora blight was also better than those against anthracnose. When $H_3PO_3$ was applied to the pepper seedlings at a concentration of $100{\mu}g\;mL^{-1}$, severe phytotoxicity was occurred. However, with applying $10{\mu}g\;mL^{-1}$ of $H_3PO_3$ showed 100% the disease control efficacy. In case of $100{\mu}g\;mL^{-1}$ $H_3PO_4$ application showed excellent antimicrobial activity against P. capsici JHAW 1-2, and 56.7% of the disease control efficacy with no phytotoxicity. To investigate the control efficacy against anthracnose, conidia suspension was inoculated with non-wound and wound inoculation method on pepper fruit. Among 6 compounds, only $100{\mu}g\;mL^{-1}$ of $H_3PO_3$ and $H_3PO_4$ had a activity of more than 70%, but the control activity on other treatments was minimal or unacceptable.

• Korean journal of applied entomology
• /
• v.25 no.1 s.66
• /
• pp.41-46
• /
• 1986

Exogenous factor and nutrients affecting for conidial germination of Colletetrichum dematium f. sp. capsicum causing red pepper anthracnose were studied by slide germination test. Optimum temperature of conidial germination was at $28^{\circ}C$, ranging 15 to $35^{\circ}C$. Optimum pH was at 5.5, ranging 4.5 to 8.0, and more than 90% of relative humidity (RH) was optimum. Poor conidial germination of the fungus was observed on sterile distilled water, but potato sucrose broth (PSB), red pepper fruit broth (RPFB), green pepper fruit broth (GPFB) and pepper leaf broth (PLB) furnished a satisfactory nutrients for conidial germination. Exogenous supply of carbon and nitrogen sources were essential for conidial germination, while potassium, phosphorous and sulfur were not evident as that for carbon and nitrogen. Soluble starch was the most suitable as a carbon source for conidial germination and followed by D-glucose, D-galactose and lactose in that order. Maximum germination was attained in the $1{\times}10^4$ conidia per ml. Germination was decreased with increment of conidial concentration, and in the density of $5{\times}10^4$ conida per ml, germination was nearly supipressed. It suggested existing a self-inhibitor. Non-washed conidia germinated more than washed conidia, and conidial germination was also gradually decreased by increasing conidial density.

• Research in Plant Disease
• /
• v.29 no.3
• /
• pp.268-275
• /
• 2023

This study was conducted to confirm the utilization of Pleurospermum camtschaticum root extract as an organic agricultural material. Antioxidant activity of P. camtschaticum root extract, closely related to antibacterial activity, increased in a dose-dependent manner. In mycelial growth inhibitory activity, 100% P. camtschaticum root extract supressed over 70% for Colletotrichum coccodes and over 68% for Colletotrichum dematium. In the pepper fruit anthracnose development test, the size of the lesion decreased in a dose-dependent manner, which showed the same tendency as the previous results in inhibitory activity on mycelial growth. In the pepper seed germination and red pepper growth promotion test of P. camtschaticum root extract, oposite results was confirmed. The lower the concentration, the more the seed germination and growth promotion effects were shown. The phenol content of pepper leaves was also measured after pepper growth promotion test have been completed. The phenol content related to antibacterial activity increased in all treated groups compared to the untreated group. Therefore, the results of this study showed the possibility of development as an organic material.

• The Korean Journal of Pesticide Science
• /
• v.14 no.4
• /
• pp.407-414
• /
• 2010

Bacillus subtilis strains isolated from different regions of Korea were screened for their plant growth promotion and induced systemic resistance (ISR) in tomato and red-pepper. The plant growth promotion on red-pepper and tomato revealed maximum plant height (22.73 cm) on red pepper treated with B. subtilis strain JE 21-1 and 30.18cm in case of tomato treated with B. subtilis strain JE 8-1. There was also significant improvement in root and shoot dry weight in both the plants. The strain JE 21-1 showed better promise for all growth parameters in red-pepper and tomato when compared to other strains and positive check BTH. Different strains screened in square plate method also revealed maximum plant height and leaf width, and suppressed anthracnose on red pepper in case of strain JE 21-1 at $10^6$ and $10^7$ cells/ml when compared to other strains. In all the bacterial inoculations the population was significantly high when compared to untreated check. In plant growth promotion with respect to fruit length and weight, fruit length was maximal in treating with JE 9-4 and ES 2-2, while fruit weight was maximal in treating with JE 3-6, ES4-2, ES2-2 and JE 21-2 on red pepper. In case of tomato, comparatively better fruit weight was in JE 21-1, ES 3-3 and JE 10-2 when compared to BTH and untreated control. The soft rot disease caused by Pectobacterium carotovorum SCCI was completely suppressed in case of transgenic tobacco harboring GUS gene related to PR1a and increased the level of salicylic acid significantly in combined application of JE 9-4 on par with BTH. Thus, this study clarified some potential Bacillus subtilis strains for plant growth promotion and ISR in red-pepper and tomato.

• Research in Plant Disease
• /
• v.18 no.1
• /
• pp.1-9
• /
• 2012

A total of 20 agricultural organic materials including inorganic compounds, plant oils and plant extracts were used in the study for assessing the control efficacy on pepper diseases. Among inorganic compounds, only copper hydroxide showed inhibitory effect on both Phytophthora capsici causing Phytophthora blight and Colletotrichum acutatum causing anthracnose. Phosphorous acid inhibited the growth of P. capsici on PDA, and Sulfur/quicklime had it on that of C. acutatum. Plant essential oil, rosemary oil, and rapeseed oil among plant oils and plant extract of Japanese apricot/ginkgo nut inhibited the mycelial growth of the two pathogens. In the screening using pepper plant seedlings, the control efficacy on Phytophthora blight in 6-leaf stage of seedling was superior to that in 4-leaf stage of seedling. A protective effect on Phytophthora blight was displayed by copper hydroxide, sulfur/quicklime, water soluble calcium, phosphorous acid, plant essential oil, and cloves extract. When C. acutatum was inoculated by the non-wound method, copper hydroxide and rapeseed oil showed excellent protective activities with control values of 91.3% and 82.6%, respectively. However, copper hydroxide did not show any activity, when C. acutatum was inoculated after wounding pepper fruits. All organic materials never showed the curative effect on Phytophthora blight and anthracnose in pepper seedling assay and fruit assay.

• The Plant Pathology Journal
• /
• v.25 no.3
• /
• pp.205-212
• /
• 2009

Colletotrichum acutatum was the main cause of the recent outbreaks of anthracnose on pepper fruit in Korea. To facilitate molecular analysis of C. acutatum, we generated an arginine auxotrophic mutant of the C acutatum strain JC24 using a targeted gene replacement strategy. A 3.3-kb genomic region carrying an ortholog (designated CaARG2) of the fungal gene encoding N-acetylglutamate synthase, the first enzyme of arginine biosynthesis in fungi, was deleted from the fungal genome. The mutant exhibited normal growth only when arginine was exogenously supplied into the culture medium. Transformation of the arginine auxotrophic mutant with a plasmid DNA carrying an intact copy of CaARG2, which was smaller than the deleted region in the mutant, not only caused random vector insertions in the fungal genome, but also recovered both hyphal growth and pathogenicity of the mutant to the wild-type level. Using this new selection system, we have successfully developed a restriction enzyme-mediated integration procedure, which would provide an economically efficient random mutagenesis method in C. acutatum.

• Current Research on Agriculture and Life Sciences
• /
• v.8
• /
• pp.35-44
• /
• 1990

Sixty two lines of pepper including Korean local cultivars and introductions were planted out to the experiment farm of Kyungpook National University for seed increase, and 16 plant and fruit characters including days to flower were recorded. In days to flower, KC85(Chilgok Dongmyung) and KC116(PI308791), KC154(Cherry Sweet), and KC185(Choseongochu) were the earliest with 83 days, and KC139(Serrano chili) and KC103(PI297488) were the latest with 126 days. In fruit detachment force, KC85(Chilgok dongmyung) was the tenderest with 0.45kg and KC162(PI22444) was the toughest with 3.34kg. In powdery mildew incidence, KC10(Pimiento), KC23(PI224423), KC51(PI257044), KC56(PI257053), KC126(PI358812), KC119(PI322719), KC143(Emerald Giant), KC148(VR-2), KC163(PI224445), KC163(Papari Mild) were the least diseased. Anthracnose was least on KC39(Serrano Chili). Collection and introduction of pepper germplasm was continued. Fourteen Korean local cultivars and 25 foreign cultivars including 2 wild species were additionally collected or introduced.