• Research in Plant Disease
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• v.10 no.1
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• pp.78-81
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• 2004

The resistance of 10 varieties of cucumber (Cucumis sativus L.) to powdery mildew, caused by Sphaerotheca fusca, was evaluated by a leaf disk assay. Leaf disks (10 mm in diameter) were removed from fully expanded leaves and then placed in petri dishes containing 0.16％ water agar amended with benzimidazole. Leaf disks were inoculated by dropping a 10 $\mu$l of conidia suspension. Conidiophore formation of powdery mildew was the greatest at $25^{\circ}C$. The response of the host to powdery mildew, based on the inoculation onto disks of the first leaf, highly correlated with results obtained from harvesting stage of cucumber plants in greenhouse test (r = 0.99$^{**}$). It is indicating that a leaf disk assay may precisely predict the response of cucumber plant to S. fusca.a.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.380-389
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• 2010

Transgenic herbicide-resistant sweet potato plants [Ipomoea batatas (L.) Lam.] produced through a biolistic transformation were used in this study. The objective of this research was to find out a rapid and reliable assay method for confirming glufosinate-ammonium resistance. The techniques tested include whole-plant bioassay, one leaf bioassay, and leaf disk bioassay. Parameters investigated in this study were leaf injury and ammonium accumulation at 1 and 5 days after treatment of glufosinate-ammonium. In the leaf disk bioassay, leaf injury of the transgenic line 7171 was 1.9-fold less affected by glufosinate-ammonium than the wild type. The leaf injury of 7171 in one leaf and whole-plant bioassays was 59- and 92-fold less affected by glufosinate-ammonium, respectively, compared with that of the wild type. Leaf disk, one leaf, and whole-plant bioassays showed that ammonium accumulation of the 7171 was 2 to 20-, 4 to 43-, and 6 to 115-fold less affected by 0.5-5 mM glufosinate-ammonium than that of the wild type. All three bioassays successfully distinguished the resistance from the transgenic lines, but one leaf bioassay is the simplest and quickest. Leaf injury and ammonium accumulation were the same in leaves 1, 3, 5, 7, and 10 of 3 mM glufosinate-ammonium treated plants or nontreated plants. The one leaf bioassay was chosen as the standard procedure for future confirmation of resistance in transgenic sweet potato because it is a rapid and reliable assay.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.400-404
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• 2011

Safflower is called as the 'beneficial flower' because 'it helps human health', and it was introduced as red flower in Tonguibogam due to the red color of floral leaf. From old times, it has been used for the material of cloth and rouge. Recently, polyphenol compound, the main ingredient of safflower, known as anti-aging and anti-oxidizing material in the healthy food industry becomes the emerging hot topic. This study aims to confirm by DDT (Disk Diffusion Test) assay, MTT assay, and NF-${\kappa}$B Luciferase activity inhibition assay in vitro that polyphenol compound, which is the main ingredient of safflower, has the anti-microbial efficacy to inhibit the growth of acne germs that make troubles for the teenagers or middle aged. Also it aims to evaluate its clinical efficacy on the acne skin, utilizing the facial cleansing cosmetic form of soap sample. This study can contribute to take a major step forward to the development of cosmetic soap for acne in the cosmeceutical industry.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2138-2140
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• 2016

The goal of this study was to identify a source of natural plant compounds with inhibitory activity against pepper mild mottle virus (PMMoV). We showed, using a half-leaf assay, that murrayafoline-A (1) and isomahanine (2) isolated from the aerial parts of Glycosmis stenocarpa have inhibitory activity against PMMoV through curative, inactivation, and protection effects. Using a leaf-disk assay, we confirmed that 2 inhibited virus replication in Nicotiana benthamiana. Using electron microscopy, we found that a mixture of the virus with 2 resulted in damage to the rod-shaped virus.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.231-243
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• 2020

Rice blast, caused by Magnaporthe oryzae, is one of the most destructive rice diseases worldwide. The aim of this study was to screen bacterial isolates to efficiently prevent the occurrence of rice blast. A total of 232 bacterial isolates were extracted from nonrhizospheric rice soil and were screened for antifungal activity against M. oryzae using a leaf segment assay. Strains S170 and S9 showed significant antagonistic activity against M. oryzae in vitro and in leaf disk assays, and controlled M. oryzae infection under greenhouse conditions. The results showed that strains S170 and S9 could effectively control rice leaf blast and panicle neck blast after five spray treatments in field. This suggested that the bacterial strains S170 and S9 were valuable and promising for the biocontrol of rice disease caused by M. oryzae. Based on 16S rDNA, and gyrA and gyrB gene sequence analyses, S170 and S9 were identified as Bacillus amyloliquefaciens and B. pumilus, respectively. The research also demonstrated that B. amyloliquefaciens S170 and B. pumilus S9 could colonize rice plants to prevent pathogenic infection and evidently suppressed plant disease caused by 11 other plant pathogenic fungi. This is the first study to demonstrate that B. amyloliquefaciens and B. pumilus isolated from nonrhizospheric rice soil are capable of recolonizing internal rice stem tissues.