• The Plant Pathology Journal
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• v.26 no.2
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• pp.149-153
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• 2010

Biological and structural mechanisms of the nematode disease development in chili pepper caused by the root-knot nematode, Meloidogyne incognita, were investigated. Out of 39 chili pepper cultivars/lines tested, six were found resistant, while 33 were susceptible to M. incognita, of which a susceptible cultivar Chilseongcho and three resistant cultivar/lines CM334, 02G132 and 03G53 with different resistance degrees were selected for microscopic studies on the disease development. Gall formation was greatly reduced in the resistant cultivars/lines. Nematode penetration occurred both in the susceptible and resistant chili pepper roots; however, the penetration rates were significantly lowered in the three resistant peppers compared to the susceptible pepper cv. Chilseongcho. In the susceptible pepper, giant cells were extensively formed with no discernible necrosis around the nematode feeding sites. In the highly resistant pepper cultivar CM334, no giant cell was formed, but extensive necrosis formation was observed around the penetrating nematodes. In the other two resistant pepper lines (02G132 and 03G53), both giant cells and prominent necroses were formed, and the necrotic responses appeared to inhibit the further development of giant cells or accelerate their early degeneration. Although the nematode penetration was retarded significantly in the resistant cultivar/lines, all of the above results suggest that the disease resistance of pepper may be related to post-infectional defense mechanisms (nematode growth and development) more than pre-infectional ones (penetration and establishment). Variations in structural modifications in the resistant cultivar/lines may reflect their genetic differences related to the nematode resistance.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.277-281
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• 2012

Bacillus sp. NAAS-1 isolated from the field of Chili pepper was tested for biocontrol activity against anthracnose pathogen of Chili pepper caused by Colletotrichum acutatum. The antifungal activity of Bacillus sp. NAAS-1 culture broth was compared with synthetic fungicide containing carbendazim (40%) and kasugamycin (3.45%). Bacillus sp. NAAS-1 showed a similar fungicidal activity against the anthracnose pathogen at the concentration of 50 ${\mu}L/mL$ in comparison to the fungicide containing carbendazim (40%) and kasugamycin (3.45%) using a cup method. Bacillus sp. NAAS-1 also exhibited its potent fungicidal activity against the anthracnose in vivo test at the concentration of 50 ${\mu}L/mL$ when compared to the fungicide containing carbendazim (40%) and kasugamycin (3.45%).

• The Plant Pathology Journal
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• v.25 no.2
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• pp.113-120
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• 2009

Microscopic study of chili pepper (Capsicum annuum L.) infected with Phytophthora capsici, causing Phytophthora blight of chili pepper, was conducted to compare histological and cytological characteristics in the root and stem of susceptible (C. annuum cv. Bugang) and resistant (C. annuum cv. CM334) pepper cultivars. The susceptible pepper roots and stems were extensively penetrated and invaded by the pathogen initially into epidermal cells and later cortical and vascular cells. Host cell walls adjacent to and invaded by the infecting hyphae were partially dissolved and structurally loosened with fine fibrillar materials probably by cell wall-degrading enzymes of the pathogen. In the resistant pepper, the pathogen remained on root epidermal surface at one day after inoculation, embedded and captured in root exudation materials composed of proteins and polysaccharides. Also the pathogen appeared to be blocked in its progression at the early infection stages by thickened middle lamellae. At 3 days after inoculation, the oomycete hyphae were still confined to epidermal cells of the root and at most outer peripheral cortical cells of the stem, resulting from their invasion blocked by wound periderms formed underneath the infection sites and/or cell wall appositions bounding the hyphal protrusions. All of these aspects suggest that limitation of disease development in the resistant pepper may be due to the inhibition of the pathogen penetration, infection, invasion, and colonization by the defense structures such as root exudation materials, thickened middle lamellae, wound peridems and cell wall appositions.

• The Plant Pathology Journal
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• v.34 no.1
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• pp.1-10
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• 2018

A previously unreported bacterial disease on chili pepper (Capsicum annuum L.) seedlings affecting as many as 4% of seedlings was observed in greenhouses in Chihuahua, Mexico (Delicias and Meoqui counties). Initial lesions appeared as irregular small spots on leaves and brown necrosis at margins tips were observed. Later, the spots became necrotic with a chlorotic halo. Advanced disease was associated with defoliation. A Gram negative, rod-shaped bacterium was isolated from diseased chili pepper seedlings. Three inoculation methods revealed that isolated strains produce foliage symptoms, similar to those observed in naturally infected seedlings. Pathogenic strains that caused symptoms in inoculated seedlings were re-isolated and identified to fulfill koch's postulate. Polyphasic approaches for identification including biochemical assays (API 20E and 50CH), carbon source utilization profiling (Biolog) and 16S rDNA, hsp60 and rpoB sequence analysis were done. Enterobacter cloacae was identified as the causal agent of this outbreak on chili pepper seedlings.

• The Plant Pathology Journal
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• v.28 no.1
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• pp.10-19
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• 2012

This study investigated the distribution of endophytic fungi obtained from the surface sterilized tissues of leaves, stems and roots of chili pepper ($Capsicum$ $annuum$ L.) plants in seedling, flowering and fruiting stages in Korea and their antifungal activity. A total of 481 isolates were recovered and were identified using molecular techniques. Based on rDNA ITS gene sequence and phylogenetic analysis, 21 fungal genera were characterized, belonging to 16 Ascomycota and 5 Basidiomycota. $Penicillium$ in seedling stage, $Fusarium$ in flowering stage, $Colletotrichum$ followed by $Fusarium$, $Alternaria$ and $Xylaria$ in fruiting stage was predominant and $Alternaria$, $Cladosporium$ and $Fusarium$ were common in all growth stages. Among 481 endophytes 90 phenotypes were evaluated for the antimicrobial activity against three major pathogens ($Phytophthora$ $capsici$, $Colletotrichum$ $acutatum$ and $Fusarium$ $oxysporum$) of chili pepper. Among them 16 isolates inhibited the growth of at least one test microorganisms. Three strains showed a broad spectrum antifungal activity and displayed strong inhibition against chili pepper pathogenic fungi.

• Korean journal of applied entomology
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• v.49 no.1
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• pp.23-29
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• 2010

The environmental risks of cucumber mosaic virus resistant transgenic chili peppers with the CMVP0-CP gene on non-target organisms in the agroecosystem environments was evaluated during the periods of the chili pepper growing season (June 19, July 30, August 31) in 2007. Arthropods assemblages leaves and flowers of chili peppers were quantitatively collected by using an insect vacuum collector to compare the arthropod community structures between non-transgenic chili peppers (nTR, P 915) and mosaic virus resistant transgenic chili peppers (TR, CMV-cp, line 7). There was no statistical difference in the arthropod community structure between the two types of crops, nTR and TR, at the same season, although the species richness and Shannon's index were somewhat different among seasons; indicating no effects of genetically modified peppers on the arthropod community. However, further studies were required to conclude more concretely for the potential environmental risk of the transgenic chili pepper of CMV-cp.

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

• Research in Plant Disease
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• v.23 no.4
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• pp.334-347
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• 2017

Bacterial wilt caused by Ralstonia solanacearum is an important disease in cultivation of chili pepper, causing plant death and significant yield losses. Cultivation of disease-resistant varieties is the most suitable measure to control bacterial wilt of chili pepper. To establish an efficient screening method for resistant chili pepper to R. solanacearum, six resistant or susceptible cultivars to the R. solanacearum were selected and the development of bacterial wilt on the cultivars according to several conditions was investigated. Drenching bacterial suspension into the cut roots using a scalpel was more simple and effective to distinguish resistant and susceptible cultivars than inoculation methods of root-dipping or soil-drenching without wounding. A resistant pepper, 'MC4' to R. solanacearum showed high resistance under the developed conditions which were 21- to 28-day-old pepper inoculated with $1{\times}10^8cfu/ml$ of bacterial suspension. On the other hands, the susceptible cultivars represented high disease severity under the conditions. These results indicated that we developed an efficient method to evaluate resistance of chili pepper cultivars against bacterial wilt. In addition, we successfully evaluated resistance degree of 140 commercial chili pepper cultivars to R. solanacearum using the developed method.

• Mycobiology
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• v.41 no.1
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• pp.18-24
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• 2013

Two new species of endophytic fungi were encountered during a diversity study of healthy tissues of chili pepper plants in Korea. The species were identified as Paecilomyces inflatus and Bionectria ochroleuca based on molecular and morphological analyses. Morphological descriptions of these endophytic isolates matched well with their molecular analysis. In the present study, detailed descriptions of internal transcribed spacer regions and morphological observations of these two fungi are presented.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2006.06a
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• pp.17.1-17.1
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• 2006