• The Plant Pathology Journal
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• 제36권2호
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• pp.157-169
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• 2020

Two lactic acid bacteria (LAB) designated J02 and J13 were recovered from fermented vegetables based on their ability to suppress soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) on radish. J02 and J13 were identified as Lactobacillus pentosus and Leuconostoc fallax, respectively. The ability of J02 and J13 to suppress plant diseases is highly dependent on chitosan. LAB alone has no effect and chitosan alone has only a moderate effect on disease reduction. However, J02 or J13 broth cultures plus chitosan display a strong inhibitory effect against plant pathogens and significantly reduces disease severity. LAB strains after being cultured in fish surimi (agricultural waste) and glycerol or sucrose-containing medium and mixed with chitosan, reduce three cruciferous vegetable diseases, including cabbage black spot caused by Alternaria brassicicola, black rot caused by Xanthomonas campestris pv. campestris, and soft rot caused by Pcc. Experimental trials reveal that multiple applications are more effective than a single application. In-vitro assays also reveal the J02/chitosan mixture is antagonistic against Colletotrichum higginsianum, Sclerotium rolfsii, and Fusarium oxysporum f. sp. rapae, indicating a broad-spectrum activity of LAB/chitosan. Overall, our results indicate that a synergistic combination of LAB and chitosan offers a promising approach to biocontrol.

• 식물병연구
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• 제10권1호
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• pp.8-12
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• 2004

2003년 7월, 경상북도 봉화지역의 인삼포장에서 인삼의 줄기가 쓰러지고 뿌리썩음증상을 보이는 인삼을 관찰하였다 병든 뿌리로부터 분리된 병원세균을 접종한 결과, 인삼의 잎은 황화되거나 검은색으로 변하여 시들었고, 줄기는 속이 텅비어 있었다. 뿌리는 접종부위가 썩으면서 주름이 생기고 차츰 검은색으로 변화였다. 이 병원세균은 인삼의 모든 부위에 대해 병원성이 인정되었고 이 병원세균의 형태 및 생리적 특성을 Bergey' manual에 기록된 세균의 특성과 비교한 결과, Serratia liquefaciens로 동정되었다. 이 세균은 아직 인삼의 병원세균으로 기록되어 있지 않기에 인삼뿌리썩음병으로 이 병원세균도 추가할 것을 제안한다.

• 식물병연구
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• 제29권3호
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• pp.310-315
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• 2023

In May 2021, characteristic soft rot symptoms, including soft, watery, slimy, black rot, wilting, and leaf collapse, were observed on melon plants (Cucumis melo) in Gokseong, Jeollanam-do, Korea. A bacterial strain, designated KNUB-06-21, was isolated from infected plant samples, taxonomically classified, and phylogenetically analyzed using 16S rRNA and housekeeping gene sequencing. Strain KNUB-06-21 was also examined for compound utilization using the API ID 32 GN system and strain KNUB-06-21 was identified as Pectobacterium brasiliense. Subsequent melon stem inoculation studies using strain KNUB-06-21 showed soft rot symptoms similar to field plants. Re-isolated strains shared phenotypic and molecular characteristics with the original P. brasiliense KNUB-06-21 strain. To our knowledge, ours is the first report of P. brasiliense causing melon soft rot disease in Korea.

• 한국균학회지
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• 제10권2호
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• pp.93-94
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• 1982

Soybean Whetzelinia rot caused by Whetzelinia sclerotiorum was observed in Jinju area. The diseased soybean plants showed withering and sudden collapse under field conditions. Diseased parts exhibited numerous black, irregularly-shaped scleratia embedded in dense white cottonly mycelium on tissue and in the pith of diseased stems. A sclerotium in the moist sand produced several apothecia under laboratary condition. The primary inoculum was supposed to originate from overwintered sclerotia of soil and soybean debris.

• 한국육종학회지
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• 제41권4호
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• pp.603-606
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• 2009

Lipoxygenase and Kunitz trypsin inhibitor protein of mature soybean [Glycine max (L.) Merr.] seed are main anti-nutritional factors in soybean seed. A new soybean cultivar, "Gaechuck#1" with the traits of black seed coat, green cotyledon, lipoxygenase2,3 and Kunitz trypsin inhibitor protein free was developed. It was selected from the population derived the cross of "Gyeongsang#1" and C242. Plants of "Gaechuck#1" have a determinate growth habit with purple flowers, brown pubescence, black seed coat, black hilum, oval leaflet shape and brown pods at maturity. Seed protein and oil content on dry weight basis have averaged 39.1% and 16.2%, respectively. It has shown resistant reaction to soybean necrosis, soybean mosaic virus, Cercospora leaf spot and blight, black root rot, pod and stem blight, and soybean pod borer. "Gaechuck#1" matured on 5-10 October with a plant height of 50 cm. The 100-seed weight of "Gaechuck#1" was 23.2g. Yield of "Gaechuck#1" was averaged 2.2 ton/ha from 2005 to 2007.

• The Plant Pathology Journal
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• 제36권5호
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• pp.418-427
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• 2020

Xanthomonas campestris pv. campestris (Xcc), the pathogen of black rot which is the most destructive disease of Brassica vegetables throughout the world. Here, we reported two novel sequence-characterized amplified region (SCAR) markers (i.e., XccR6-60 and XccR6-67) for the detection of Xcc race 6 via re-alignment of the complete genome sequences of Xcc races/strains/pathovars. The specificity of SCAR primer sets was verified by mean of PCR amplification using the genomic DNA template of Xcc races/strains/pathovars and two other plant infecting bacterial strains. The PCR result revealed that the XccR6-60 and XccR6-67 primer sets amplified 692-bp and 917-bp DNA fragments, respectively, specifically from race 6, while no visible amplification was detected in other samples. In addition, the SCAR primers were highly sensitive and can detect from a very low concentration of genomic DNA of Xcc race 6. However, the complete genome sequence of Xcc race 6 is not yet publicly available. Therefore, the cloning and sequencing of XccR6-60 and XccR6-67 fragments from race 6 provide more evidence of the specificity of these markers. These results indicated that the newly developed SCAR markers can successfully, effectively and rapidly detect Xcc race 6 from other Xcc races/strains/pathovars as well as other plant pathogenic bacteria. This is the first report for race-specific molecular markers for Xcc race 6.

• The Plant Pathology Journal
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• 제16권6호
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• pp.321-324
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• 2000

season of 2000. The disease infection usually started from flower, peduncle and young fruits, then moved to flower stalk, stem and leaves. At first, the lesions started with water-soaked, rapidly softened, and then the area gradually expanded. In severely affected film house, the rate of infected fruits reached to 28.6%. Numerous sporangiospores were formed on the diseased fruits, flower stalk, stem and leaves. Most of the sporangiospores were appeare to be rapidly dispersed in the air. The mycelia grew on the surface of host and formed stolons. Colonies on potato dextrose agar were cottony at first brownish black at maturity. Sporangia were 125.3${\times}$294.2 ${\mu}$m. globose or sub-globose with somewhat flattened base. White at first the black, many spored, and are never overhanging. Sporangiophores were 2.7-6.8${\times}$12.9-33.9 ${\mu}$m, smooth-walled, non-septate, light brown, simple, long, arising in groups of 3-5 from stolons opposite rhizoids. Sporangiophores were 8.6-21.1${\times}$6.41-1.7 ${\mu}$m, irregular, round, oval, elongate, angular and brownish-black streaked. Columella were 63.8${\times}$140.4 ${\mu}$m. brownish gray, umberella-shaped when dehisced. The causal organism was identified as Rhizopus stolonifer Lind on the basis of the morphological characteristics of the fungus. Rhizopus soft rot on squash (Cucurbita moschata) caused by the fungi has not been previously reported in Korea.

• The Plant Pathology Journal
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• 제37권5호
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• pp.476-488
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• 2021

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot for cruciferous vegetables worldwide, especially for the cole crops such as cabbage and cauliflower. Due to the lack of resistant cabbage cultivars, black rot has brought about considerable yield losses in recent years in China. Understanding of the pathogen features is a key step for disease prevention, however, the pathogen diversity, population structure, and virulence are largely unknown. In this study, we studied 50 Xcc strains including 39 Xcc isolates collected from cabbage in 20 regions across China, using multilocus sequence genotyping (MLST), repetitive DNA sequence-based PCR (rep-PCR), and pathogenicity tests. For MLST analysis, a total of 12 allelic profiles (AP) were generated, among which the largest AP was AP1 containing 32 strains. Further cluster analysis of rep-PCR divided all strains into 14 DNA groups, with the largest group DNA I comprising of 34 strains, most of which also belonged to AP1. Inoculation tests showed that the representative Xcc strains collected from diverse regions performed differential virulence against three brassica hosts compared with races 1 and 4. Interestingly, these results indicated that AP1/DNA I was not only the main pathotype in China, but also a novel group that differed from the previously reported type races in both genotype and virulence. To our knowledge, this is the first extensive genetic diversity survey for Xcc strains in China, which provides evidence for cabbage resistance breeding and opens the gate for further cabbage-Xcc interaction studies.

• Journal of Microbiology and Biotechnology
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• 제29권5호
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• pp.785-793
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• 2019

Black rot caused by Xanthomonas campestris pv. campestris (Xcc) is the most damaging disease in Brassica crops around the world. In this study, we developed a molecular marker specific to Xcc race 5. To do this, the available whole genome sequences of Xcc races/strains and Xc subspecies were aligned and identified a highly variable genomic region (XccR5-89.2). Subsequently, a primer set covering the 'XccR5-89.2' region was designed and tested against the genomic DNA of Xcc races/strains, Xc subspecies and other plant-infecting bacterial strains (Pseudomonas syringae pv. maculicola and Erwinia carotovora subsp. carotovora). The results showed that the 'XccR5-89.2' primer pair amplified a 2,172-bp fragment specific to Xcc race 5. Moreover, they also amplified a 1,515-bp fragment for Xcc race 1 and an over 3,000-bp fragment for Xcc race 3. However, they did not amplify any fragments from the remaining Xcc races/strains, subspecies or other bacterial strains. The 'XccR5-89.2' primer pair was further PCR amplified from race-unknown Xcc strains and ICMP8 was identified as race 5 among nine race-unknown Xcc strains. Further cloning and sequencing of the bands amplified from race 5 and ICMP8 with 'XccR5-89.2' primers revealed both carrying identical sequences. The results showed that the 'XccR5-89.2' marker can effectively and proficiently detect, and identify Xcc race 5 from Xcc races/strains, subspecies and other plant-infecting bacteria. To our knowledge, this is the first report for an Xcc race 5-specific molecular marker.

• The Plant Pathology Journal
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• 제38권4호
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• pp.272-286
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• 2022

Black root rot (BRR) caused by Lasiodiplodia theobromae is an alarming disease of mulberry that causes tremendous economic losses to sericulture farmers in India and China. Successful control of this disease can be attained by screening germplasm and identifying resistant sources. Seventy four diseased root samples were collected from farmer's fields belonging to four major mulberry growing states of South India. Based on morpho-cultural and scanning electron microscopy studies, 57 fungal isolates were characterized and identified as L. theobromae. Phylogenetic analysis of concatenated internal transcribed spacer and β-tubulin sequences revealed variation of the representative 20 isolates of L. theobromae. Following the root dip method of inoculation, pathogenicity studies on susceptible mulberry genotypes (Victory-1 and Thailand male) recognized the virulent isolate MRR-142. Accordingly, MRR-142 isolate was used to evaluate resistance on a set of 45 diverse mulberry accessions. In the repeated experiments, the mulberry accession ME-0168 which is an Indonesian origin belonging to Morus latifolia was found to be highly resistant consistently against BRR. Eight accessions (G2, ME-0006, ME-0011, ME-0093, MI-0006, MI-0291, MI-0489, and MI-0501) were found to be resistant. These promising resistant resources may be exploited in mulberry breeding for developing BRR resistant varieties and to develop mapping populations which successively helps in the identification of molecular markers associated with BRR.