• The Korean Journal of Mycology
• /
• v.16 no.1
• /
• pp.1-8
• /
• 1988

Effect of suppression for zoosporangial germination and mycelial growth of Phyto­phthora capsici causing red pepper fruit rot, was carried out in vitro test by using $NH_4OH$ and $KNO_2$, as ammonium/ammonia, nitrite/nitrous acid and $CaCl_2$, as calcium ion. Results of in vitro tests with $NH_4OH$, $KNO_2$, and $CaCl_2$, mol solutions demonstrated that zoosporangial germination of P. capsici was inhibited about 15 to 50% compared with control, according to $NH_3$, HNO as nonionized form and $Ca^{+2}$ ions. Ammonia concentration$(NH_3)$ was proportionally increased by high pH level and mol concentration, whereas low pH and high mol concentration showed rather higher concentration of $HNO_2$. Ammonia were more toxic at pH 8 than at pH 7 under the same concentration, while nitrous acid$(HNO_2)$ was more toxic than at pH 8. The zoosporangial germination inhibition in the ammonium/ammonia and nitrite/nitrous acid solutions demonstrated that $NN_3$, and $HNO_2$, were primarily responsible for the inhibition at lower concentration and mor" toxic by increasing concentration. $Ca^{+2}$ ions showed that zoosporangial germination was inhibitory by high pH level and increasing mol concentration in comparison with buffer conlrol. pH levels affected to mycelial growth of the fungus, and especially, high pH caused rather retardation of mycelial growth. There was no definite inhibitory response of mycelial growth at various degree concentrations of the toxicant solutions.

• Korean journal of applied entomology
• /
• v.24 no.3 s.64
• /
• pp.117-121
• /
• 1985

Through the laboratory and vinyl house experiments, the effects of inoculum density, plant age and temperature on the incidence of Phytophthora crown rot of pepper (Capsicum annum L.) were investigated. The propagule survival was greater in the natural soil than in autoclaved soil within first 2 weeks when the sporangial suspension of the pathogenic fungus was incorporated into soil, thereafter the survivability reduced rapidly. The propagule was not detectable in 35 days by means of Papavizas selective medium neither in natural nor in autoclaved soil. At least 5 sporangia per gram soil were required to induce crown rot for 30 days old pepper seedlings. Further increase in inoculum concentration above this threshold level resulted in higher disease incidence and shorter incubation period. When the same amount of inoculum was infested, higher disease incidence was observed for younger plants until 3 weeks after inoculation. On the other hand after 4 weeks this tendency was not extended any more. Younger plants were recognized as having shorter incubation period upon infection, however, the days from first symptom appearance to complete death were not significantly different among differently aged seedlings. Exposure of inoculated pepper seedlings to $25^{\circ}C$ resulted in highest infection rates and followed by those to $30^{\circ}C\;and\;20^{\circ}C$ but no disease was found at $15^{\circ}C\;and\;35^{\circ}C$ for 10 days. When the plants previously incubated at different temperature for 10 days were moved to $25^{\circ}C$ room temperature, prior exposure to $20^{\circ}C\;and\;30^{\circ}C$ brought continuous disease development. Even those plants preincubated at $15^{\circ}C$ were diseased up to 50%. But the prior exposure to $35^{\circ}C$ induced no symptom developed, indicating no seedlings infected at all.

• Current Research on Agriculture and Life Sciences
• /
• v.12
• /
• pp.29-34
• /
• 1994

A leading sweet pepper cultivar, Keystone Resistant Giant #3, was crossed with a line with resistance to Phytophthora capsici, PI201232, for incorporation of the resistance and to study the inheritance of resistance to the disease. Seedlings of parents, $F_1$, $F_2$ and backcross populations of a cross between Keystone Resistant Giant #3 and PI201232 were inoculated with zoospore suspension of P. capsici at 36 days after seeding. Most of the $F_1$ seedlings survied the inoculation and this suggested that resistance is dominant over susceptibility. The number of survived plants in $F_2$ population was, however, much less than the killed. All the plants in a backcross to Keystone Resistant Giant #3 were killed. Therefore, the observed numbers did not fit the expected ratio for segregation of one or two dominant alleles as previously reported. The resistance to P. capsici appeared to be inherited in a quantitative mode in evaluation of root rot. Resistant individuals in $F_2$ population were selected and a breeding program for incorporation of the resistance to P. capsici by backcross method is continued.

• Journal of Life Science
• /
• v.12 no.3
• /
• pp.264-273
• /
• 2002

We have isolated and artificially expressed three cDNA clones of Capsicum annuum PR5 genes for elucidating the antifungal activity against Phytophthora capsici which contracted a hot pepper root rot in field condition. Three divergent PR5 proteins from hot pepper were designated as CAPR5-1 and CAPR5-2 from susceptible cultivar (Subicho) as well as CAPR5-3 from resistant cultivar (CM331) in response to P. capsici. The cDNA similarity was found over 80% of identity among the three CAPR5s, and deduced amino acid sequence was characterized that all of CAPR5s contained 16 cysteine residues which possibly had a significant role in the structural formation. The result of genomic DNA blot showed that CAPR5-1 and CAPR5-2 existed as single copy in the Subicho genome. Three recombinant CPARs in E. coli were identified by SDS-PACE, and each expressed protein was treated on the PDA medium which contained cultured pathogens. Although three CAPR5 proteins did not affected the hyphal growth of Glomerella glycines and Colletotrichum fagenarium, CAPR5-1, CAPR5-2, and CAPR5-3 showed a specific antifungal activities against P. capsici.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.202-202
• /
• 2022

Recently days, soybean production in paddy field is increasing, from 4,422 ha in 2016 to 10,658 ha in 2021 in Korea. It is easy for Phytophthora stem and root rot (PSR) occurring in paddy field condition, when it is poorly drained soils with a high clay content, and temporary flooding and ponding. Therefore PSR resistant soybean cultivar is required. The objective of this study is to identify QTL region and candidate genes relating to PSR resistance of the race in main soybean cultivation area in Korea. 210 soybean materials including cultivars and germplasm were used for inoculation and genome-wide association study (GWAS). Inoculation was conducted using stem-scar method with 2 replications in 2-year for the race 3053 from Kimje and 3617 from Andong. 210 materials were genotyped with Soya SNP 180K chip, and structure analysis and association mapping were conducted with QTLMAX V2. The results of inoculation showed that survival ratio ranged from 0% to 96.7% and mean 9.7% for 3053 and ranged from 0% to 100% and mean 7.6% for 3617. Structure analysis showed linkage disequillibrium (LD) was decayed below r²=0.5 at 335kb of SNP distance. Significant SNPs (LOD>7.0) were identified in Chr 1, 2, 3, 4, 5, 11, 14, 15 for 3053 and Chr 1, 2, 3, 7, 10, 14 for 3617. Especially, LD blocks (AX-90455181;15,056,628bp~AX-90475572;15,298,872bp) in Chr 2 for 3053 and 3067 were duplicated. 29 genes were identified on these genetic regions including Glyma.02gl47000 relating to ribosome recycling factor and defense response to fungus in Soybase.

• Journal of Plant Biotechnology
• /
• v.29 no.4
• /
• pp.229-233
• /
• 2002

Ferritin is ubiquitous in bacteria, animals and plants. Ferritin is thought to play two main roles in living cells to provide iron for the synthesis of iron protein such as ferretoxin and cytochromes and to prevent damage from radicals produced by iron/dioxygen interaction. To enhance the resistance of potato to Erwinia carotovora, the soybean ferritin gene was introduced into the potato either under CaMV 35S or hsr203J promoter. Potato transgenic plants were screened by PCR analysis using specific primers to the ferritin gene. Expression of ferritin gene under CaMV 35S and hsr203J promoter in potato transgenic plants was confirmed by northern blot analysis. hsr203J promoter known to pathogen inducible in tobacco drives the induction upon Phytophthora infestan in potato and the transcript level of ferritin gene was extremely high after 24 hours post inoculation. One of transformants under CaMV 35S promoter was increased 2.5 fold than untransformant. Each one of transgenic potato containing gene promoter CaMV 35S and hsr203J-ferrtin fusion exhibited tolerance against potato soft rot.

• Research in Plant Disease
• /
• v.22 no.4
• /
• pp.284-288
• /
• 2016

A plant growth promoting rhizobacterium, Bacillus vallismortis BS07M, was formulated as a clay pellet (CP) to evaluate its pepper growth promotion and induced resistance against various diseases under field and storage conditions. Peppers were grown in 50-hole tray containing potting mixture with CP in seedling raising stage, and then it was transplanted into a field. After transplanting, pepper plants treated with CP in seedling raising stage increased shoot growth and reduced disease severity caused by Phytophthora capsici in detached pepper leaves compared to untreated control. Moreover, treatment with CP in seedling raising stage increased fruit weight per plant; after harvesting, pepper fruits shown reduced diameter of lesions by Colletotrichum acutatum, and occurrance of soft rot in storage condition. These results indicated that CP could affect plant growth and induced resistance in pepper plants under field condition, and maintenance of fruit during storage.

• Research in Plant Disease
• /
• v.8 no.3
• /
• pp.146-161
• /
• 2002

Incidence of soilborne diseases, as a major cause of failure of continuous monocropping becomes severe in recent years. For examples, recent epidemics of club root of chinese cabbage, white rot of garlic, bacterial wilt of potato, pepper phytophthora blight, tomato fusarium wilt and CGMMV of watermelon are the diseases that require urgent control measures. Reasons for the severe incidence of soilborne diseases are the simplified cropping system or continuous monocropping associated with allocation of major production areas of certain crop and year-round cultivation system that results in rapid degradation of soil environment. Neglect of breeding for disease resistance relative to giving much emphasis on high yield and good quality, and cultural methods putting first on the use of chemical fertilizers are thought to be the reason. Counter-measures against soilborne disease epidemics would become most effective when the remedies are seeded for individual causes. As long-term strategies, development of rational cropping system which fits local cropping and economic condition, development and supply of cultivars resistant to multiple diseases, and improvement of soil environment by soil conditioning are suggested. In short-term strategies, simple and economical soil-disinfestation technology, and quick and accurate forecasting methods for soilborne diseases are urgent matter far development. for these, extensive supports are required in governmental level for rearing soilborne disease specialists and activation of collaborating researches to solve encountering problems of soilborne diseases.

• Korean Journal of Microbiology
• /
• v.42 no.2
• /
• pp.135-141
• /
• 2006

We isolated a bacterium which produces antifungal substances from the Sanktpeterburg soils at Russia. The iso-lated strain was identified as Brevibacillus sp. and shown a strong antifungal activity on plant pathogenic fungi. Brevibacillus sp. KMU-391 produced maximum level of antifungal substances under incubation aerobically at $30^{\circ}C$ for 48 hours in trypticase soybean broth containing 1.0% sucrose and 1.0% polypeptone at 180 rpm and initiated pH adjusted to 7.0. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against Didymella bryoniae by dry cell weight. Butanol extract of cultured broth also shown fungal growth inhibitory activity against Botrytis cinerea KACC 40573, Botrytis fabae KACC 40962, Colletotrichum gloeosporioides KACC 40804, Colletotrichum orbiculare KACC 40808, Didymella bryoniae KACC 40669, Fusarium graminearum KACC 41040, Fusarium oxysporum KACC 40037, Fusarium oxysporum KACC 40052, Fusarium oxysporum f, sp. radicis-Iycopersici KACC 40537, Fusarium oxysporum KACC 40902, Monosporascus cannonballus KACC 40940, Phytophthora camvibora KACC 40160, Rhizoctonia solani AG-1(IA) KACC 40101, Rhizoctonia solani AG-4 KACC 40142, and Scleotinia scleotiorum KACC 41065 by agar diffusion method.

• Korean Journal of Breeding Science
• /
• v.50 no.4
• /
• pp.497-503
• /
• 2018

A strawberry variety 'Arihyang' was derived as an artificial cross between 'Tochiotome' and 'Seolhyang' in 2014. The seedling and line selections were conducted from 2014 to 2015. Preliminary and advanced yield trials of '14-5-5,' which was the final selected line, were conducted from 2015 to 2017. 'Arihyang' is suitable for forced cultivation and has strong plant vigor, uniformly large-sized fruit, and a high yield compared to those of the check variety, 'Seolhyang' and 'Maehyang.' Especially, vitamin C was at a significant level, which was approximately 15% higher than that of 'Seolhyang.' The average number of flowers per first flower cluster was 10.5, which could reduce the labor of thinning fruit. Its fruit has a conical shape, dark red color, and glossy skin. The fruit was of good quality but has recommendations for harvest at the fully ripened stage. 'Arihyang' has intermediate resistant to phytophthora crown rot, but is susceptible to powdery mildew, gray mold, anthracnose, and fusarium wilt. It is reguired to manage major diseases and pests using optimum cultivation techniques and chemical control.