• The Plant Pathology Journal
• /
• v.31 no.2
• /
• pp.195-201
• /
• 2015

Plant growth promoting rhizobacteria (PGPR) are known to confer disease resistance to plants. Bacillus sp. JS demonstrated antifungal activities against five fungal pathogens in in vitro assays. To verify whether the volatiles of Bacillus sp. JS confer disease resistance, tobacco leaves pre-treated with the volatiles were damaged by the fungal pathogen, Rhizoctonia solani and oomycete Phytophthora nicotianae. Pre-treated tobacco leaves had smaller lesion than the control plant leaves. In pathogenesis-related (PR) gene expression analysis, volatiles of Bacillus sp. JS caused the up-regulation of PR-2 encoding ${\beta}$-1,3-glucanase and acidic PR-3 encoding chitinase. Expression of acidic PR-4 encoding chitinase and acidic PR-9 encoding peroxidase increased gradually after exposure of the volatiles to Bacillus sp. JS. Basic PR-14 encoding lipid transfer protein was also increased. However, PR-1 genes, as markers of salicylic acid (SA) induced resistance, were not expressed. These results suggested that the volatiles of Bacillus sp. JS confer disease resistance against fungal and oomycete pathogens through PR genes expression.

• The Plant Pathology Journal
• /
• v.36 no.6
• /
• pp.558-569
• /
• 2020

Fusarium head blight (FHB) is a devastating fungal disease of wheat (Triticum aestivum L.). The lack of genetic resources with stable FHB resistance combined with a reliable and rapid screening method to evaluate FHB resistance is a major limitation to the development of FHB resistant wheat germplasm. The present study utilized an immature wheat spike culture method to screen wheat spike culture derived variants (SCDV) for FHB resistance. Mycotoxin concentrations determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) correlated significantly (P < 0.01) with FHB severity and disease progression during in vitro spike culture. Selected SCDV lines assessed for FHB resistance in a Fusarium field disease nursery in Carman, Manitoba, Canada in 2016 showed significant (P < 0.01) correlation of disease severity to the in vitro spike culture screening method. Selected resistant SCDV lines were also crossed with an elite cv. CDC Hughes and the progeny of F₂ and BC₁F₂ were screened by high resolution melt curve (HRM) analyses for the wheat UDP-glucosyl transferase gene (TaUGT-3B) single nucleotide polymorphism to identify resistant (T-allele) and susceptible (G-allele) markers. The progeny from the crosses were also screened for FHB severity using the immature spike culture method and identified resistant progeny grouped according to the HRM genotyping data. The results demonstrate a reliable approach using the immature spike culture to screen for FHB resistance in progeny of crosses in early stage of breeding programs.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.66.2-66
• /
• 2003

A gain-of-function mutant, SHM-11 obtained through gamma-ray mutagenesis, is resistant to rice blast caused by Magnaporthe grisea while wild type Sanghaehyanghyella is highly susceptible to the same disease. The resistance in the mutant was not race-specific when we tested with four races (KJ-201, KI-1113a, KI-313, KI-409) of M. grisea. To identify genes involved disease resistance in the gain-of-function mutant, genes specifically expressed in the mutant were selected by suppression subtractive hybridization using cDNAS of blast-inoculated mutant and wild type as a tester and a driver, respectively, Random 200 clones from the subtracted library were selected and analyzed by DNA sequencing. The sequenced genes represented three major groups related with disease resistance； genes encoding PR proteins, genes probably for phytoalexin biosynthesis, and genes involved in disease resistance signal transduction. A gene encoding a putative receptor-like protein kinase was identified as highly expressed only in the gain-of-function mutant after blast infection. The role of the putative receptor-like protein kinase gene during blast resistance will be further studied.

• The Plant Pathology Journal
• /
• v.25 no.3
• /
• pp.256-262
• /
• 2009

The potential of. nonpathogenic Fusarium oxysporum strain Avr5, either alone or in combination with chitosan and Bion, for inducing defense reaction in tomato plants inoculated with F. oxysporum f. sp lycopersici, was studied in vitro and glasshouse conditions. Application Bion at concentration of 5, 50, 100 and $500{\mu}g$/ml, and the highest concentration of chitosan reduced in vitro growth of the pathogen. Nonpathogenic F. oxysporum Avr5 reduced the disease severity of Fusarium wilt of tomato in split plants, significantly. Bion and chitosan applied on tomato seedlings at concentration $100{\mu}g$ a.i./plant; 15, 10 and 5 days before inoculation of pathogen. All treatments significantly reduced disease severity of Fusarium wilt of tomato relative to the infected control. The biggest disease reduction and increasing tomato growth belong to combination of nonpathogenic Fusarium and Bion. Growth rate of shoot and root markedly inhibited in tomato plants in response to tomato Fusarium wilt as compared with healthy control. These results suggest that reduction in disease incidence and promotion in growth parameters in tomato plants inoculated with nonpathogenic Fusarium and sprayed with elicitors could be related to the synergistic and cooperative effect between them, which lead to the induction and regulation of disease resistance. Combination of elicitors and non-pathogenic Fusarium synergistically inhibit the growth of pathogen and provide the first experimental support to the hypothesis that such synergy can contribute to enhanced fungal resistance in tomato. This chemical could provide a new approach for suppression of tomato Fusarium wilt, but its practical use needs further investigation.

• Archives of Pharmacal Research
• /
• v.29 no.9
• /
• pp.768-776
• /
• 2006

Non-alcoholic fatty liver disease (NAFLD) is common in obesity. However, weight reduction alone does not prevent the progression of NAFLD to end-stage disease associated with the development of cirrhosis and liver disease. In a previous experiment, 50% ethanol extract of Acanthopanax senticosus stem bark (ASSB) was found to reduce body weight and insulin resistance in high fat diet-induced hyperglycemic and hyperlipidemic ICR mice. To evaluate the anti-steatosis action of ASSB, insulin-resistant ob/ob mice with fatty livers were treated with ASSB ethanol extract for an 8 week-period. ASSB ethanol extract reversed the hepatomegaly, as evident in reduction of % liver weight/body weight ratio. ASSB ethanol extract also specifically lowered circulating glucose and lipids, and enhanced insulin action in the liver. These changes culminated in inhibition of triglyceride synthesis in non-adipose tissues including liver and skeletal muscle. Gene expression studies confirmed reductions in glucose 6-phosphatase and lipogenic enzymes in the liver. These results demonstrate that ASSB ethanol extract is an effective treatment for insulin resistance and hepatic steatosis in ob/ob mice by decreasing hepatic lipid synthesis.

• Journal of Ginseng Research
• /
• v.45 no.3
• /
• pp.380-389
• /
• 2021

Metabolic syndrome (MS) refers to a clustering of at least three of the following medical conditions: high blood pressure, abdominal obesity, hyperglycemia, low high-density lipoprotein level, and high serum triglycerides. MS is related to a wide range of diseases which includes obesity, diabetes, insulin resistance, cardiovascular disease, dyslipidemia, or non-alcoholic fatty liver disease. There remains an ongoing need for improved treatment strategies for MS. The most important risk factors are dietary pattern, genetics, old age, lack of exercise, disrupted biology, medication usage, and excessive alcohol consumption, but pathophysiology of MS has not been completely identified. Korean Red Ginseng (KRG) refers to steamed/dried ginseng, traditionally associated with beneficial effects such as anti-inflammation, anti-fatigue, anti-obesity, anti-oxidant, and anti-cancer effects. KRG has been often used in traditional medicine to treat multiple metabolic conditions. This paper summarizes the effects of KRG in MS and related diseases such as obesity, cardiovascular disease, insulin resistance, diabetes, dyslipidemia, or non-alcoholic fatty liver disease based on experimental research and clinical studies.

• The Plant Pathology Journal
• /
• v.28 no.1
• /
• pp.68-74
• /
• 2012

Biocontrol microbes have mainly been screened among large collections of microorganisms $via.$ nutrient-rich $in$ $vitro$ assays to identify novel and effective isolates. However, thus far, isolates from only a few genera, mainly spore-forming bacilli, have been commercially developed. In order to isolate field-effective biocontrol microbes, we screened for more than 200 oligotrophic bacterial strains, isolated from rhizospheres of various soil samples in Korea, which induced systemic resistance against the soft-rot disease caused by $Pectobacterium$ $carotovorum$ SCC1; we subsequently conducted in $planta$ bioassay screening. Two oligotrophic bacterial strains were selected for induced systemic disease resistance against the $Tobacco$ $Mosaic$ $Virus$ and the gray mold disease caused by $Botrytis$ $cinerea$. The oligotrophic bacterial strains were identified as $Pseudomonas$ $manteilii$ B001 and $Bacillus$ $cereus$ C003 by biochemical analysis and the phylogenetic analysis of the 16S rRNA sequence. These bacterial strains did not exhibit any antifungal activities against plant pathogenic fungi but evidenced several other beneficial biocontrol traits, including phosphate solubilization and gelatin utilization. Collectively, our results indicate that the isolated oligotrophic bacterial strains possessing induced systemic disease resistance could provide useful tools as effective biopesticides and might be successfully used as cost-effective and preventive biocontrol agents in the field.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.201-201
• /
• 2022

Rice bakanae disease is a serious global threat in major rice-cultivating regions worldwide causing high yield loss. It is caused by the fungal pathogen Fusarium fujikuroi. Varying degree of resistance or susceptibility to bakanae disease had been reported among Korean japonica rice varieties. We developed a modified in vitro bakanae disease bioassay method and tested 31 Korean japonica rice varieties. Nampyeong and Samgwang varieties showed highest resistance while 14 varieties including Junam and Hopum were highly susceptible with 100% mortality rate. We carried out mapping QTLs for bakanae disease resistance with four F2:F3 populations derived from the crosses between Korean japonica rice varieties. The Kompetitive Allele-Specific PCR (KASP) markers developed in our laboratory based on the SNPs detected in Korean japonica rice varieties were used in genotyping F2 plants in the populations. We found four major QTLs on chromosome 1, 4, 6, and 9 with LOD scores of 21.4, 6.9, 6.0, and 60.3, respectively. In addition, we are doing map-based cloning of the QTLs on chromosome 1 and 9 which were found with Junam/Nampyeong F2:F3 population and Junam/Samgwang F2:F3 population, respectively. These QTLs will be very useful in developing bakanae disease resistant high quality rice varieties.

• Korean Journal of Plant Tissue Culture
• /
• v.27 no.4
• /
• pp.317-323
• /
• 2000

Molecular genetic techniques can now be applied to the development of advanced plant genotypes, either through genetic transformation or genomic approaches which allow researchers to transfer specific traits using molecular markers. In this paper, we discuss the use of these techniques towards understanding the genetics of blackleg resistance in Brassica. In a comparative mapping study between Arabidopsis thaliana and Brassica napus, 6 R-ESTs, 7 B. napus RFLP markers and a B. napus EST were located in a collinear region of N7 (B. napus) and chromosome 1 (A. thaliana). One of the A. thaliana R-ESTs and 4 of the B. napus RFLPs co-segregated and mapped to the LmRl locus for blackleg resistance. Introgression of blackleg resistance from wild relatives is also investigated with the possibility of accelerating the introgression process via marker assisted selection.

• Journal of Crop Science and Biotechnology
• /
• v.11 no.2
• /
• pp.101-106
• /
• 2008

To identify inheritance of clubroot disease resistance genes in Chinese cabbage, seedling tests of $BC_1P_1,\;BC_1P_2$, and $F_2$ populations derived from $F_1$ hybrid(var. CR Saerona) using single spore isolate(race 4 identified with William's differential host) from Plasmodiophora brassciae were conducted. Resistance(R) and susceptible(S) plants segregated to 1:0 in backcross to the resistant parent. The $F_2$ population segregated in a 3(R):1(S) ratio. This result implied that the resistance of clubroot disease is controlled by a single dominant gene to the race 4 of P. brassicae in CR Saerona. To develop DNA markers linked to clubroot resistance genes, 185 plants of CR Saerona among $F_2$ populations were used. A total of 300 arbitrary decamer was applied to $F_2$ population using BSARAPD(Bulked segregant analysis-Randomly amplified polymorphic DNA). One RAPD marker linked to clubroot resistance gene in CR Saerona($OPJ_{1100}$) was identified. This marker was 3.1 cM in distance from resistance gene in $F_2$ population. This marker may be useful for a marker-assisted selection(MAS) and gene pyramiding of the clubroot disease resistant gene in Chinese cabbage breeding programs.