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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Plant Pathology Journal
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Korean Society of Plant Pathology
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Volume & Issues
Volume 24, Issue 4 - Dec 2008
Volume 24, Issue 3 - Sep 2008
Volume 24, Issue 2 - Jun 2008
Volume 24, Issue 1 - Mar 2008
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At Death`s Door: Alternaria Pathogenicity Mechanisms
Lawrence, Christopher B. ; Mitchell, Thomas K. ; Craven, Kelly D. ; Cho, Yang-Rae ; Cramer, Robert A. ; Kim, Kwang-Hyung ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 101~111
DOI : 10.5423/PPJ.2008.24.2.101
The fungal genus Alternaria is comprised of many saprophytic and endophytic species, but is most well known as containing many notoriously destructive plant pathogens. There are over 4,000 Alternaria/host associations recorded in the USDA Fungal Host Index ranking the genus 10th among nearly 2,000 fungal genera based on the total number of host records. While few Alternaria species appear to have a sexual stage to their life cycles, the majority lack sexuality altogether. Many pathogenic species of Alternaria are prolific toxin producers, which facilitates their necrotrophic lifestyle. Necrotrophs must kill host cells prior to colonization, and thus these toxins are secreted to facilitate host cell death often by triggering genetically programmed apoptotic pathways or by directly causing cell damage resulting in necrosis. While many species of Alternaria produce toxins with rather broad host ranges, a closely-related group of agronomically important Alternaria species produce selective toxins with a very narrow range often to the cultivar level. Genes that code for and direct the biosynthesis of these host-specific toxins for the Alternaria alternata sensu lato lineages are often contained on small, mostly conditionally dispensable, chromosomes. Besides the role of toxins in Alternaria pathogenesis, relatively few genes and/or gene products have been identified that contribute to or are required for pathogenicity. Recently, the completion of the A. brassicicola genome sequencing project has facilitated the examination of a substantial subset of genes for their role in pathogenicity. In this review, we will highlight the role of toxins in Alternaria pathogenesis and the use of A. brassicicola as a model representative for basic virulence studies for the genus as a whole. The current status of these research efforts will be discussed.
Pre-Infection Behavior of the Pitch Canker Fungus Fusarium circinatum on Pine Stems
Thoungchaleun, Vilakon ; Kim, Ki-Woo ; Lee, Don-Koo ; Kim, Chang-Soo ; Park, Eun-Woo ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 112~117
DOI : 10.5423/PPJ.2008.24.2.112
Pre-infection behavior of Fusarium circinatum on stems of pine species was investigated with scanning electron microscopy. Two-year-old stems of Pinus densiflora and p. rigida were inoculated with the fungal conidial suspension and subjected to
for up to 16 hr. Most microconidia germinated 12 hr after inoculation on pine stems. Conidia produced germ tubes from either one or both ends of microconidia. Germ tubes grew over the stem surface and appeared to enter host tissues through natural openings on pine stems. Surface cracks in the cork were entrance sites of germ tubes of F. circinatum. In addition, host cell wall cracks were often found at the tip of germ tubes. The cuticle appeared to be eroded either at the tip of germ tubes or around germlings. Germ tubes also produced appressoria-like structures, exhibiting swollen tips of germ tubes on the stem surface. There seems to be no significant differences in the pre-infection behavior of F. circinatum on stems between the two pine species.
Cladosporium sp. is the Major Causal Agent in the Microbial Complex Associated with the Skin Sooty Dapple Disease of the Asian Pear in Korea
Park, Young-Seob ; Kim, Ki-Chung ; Lee, Jang-Hoon ; Cho, Song-Mi ; Choi, Yong-Soo ; Kim, Young-Cheol ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 118~124
DOI : 10.5423/PPJ.2008.24.2.118
Skin sooty dapple disease, a fungal disease that lowers Asian pear fruit quality, has emerged recently in Korea but has not yet been thoroughly characterized. This disease affects the surface of fruit, leaves, and young shoots of the Asian pear, typically appearing as a dark or pale black dapple on the fruit surface. The disease initiates on the fruit with small circular lesions that become bigger, eventually spreading to form large circular or indefinite lesions. Sparse dark or flourishing white-greyish aerial mycelia and appearance of a dark or pale black dapple on the fruit surface are typical signs of this disease. The disease was severe during cold storage of the Niitaka and Chuhwangbae varieties, but more limited on the Gamcheonbae and Hwangkeumbae varieties. To identify causal pathogens, 123 fungal isolates were obtained from lesions. The fungi that caused typical skin sooty dapple disease symptoms in our bioassay were identified. Based on their morphological characteristics, 74% of the isolates were Cladosporium sp. and 5-7 % of the isolates were Leptosphaerulina sp., Tripospermum sp., or Tilletiopsis sp. None of the isolates caused severe soft rot by injection to a wound plug, but some of the Cladosporium sp. isolates caused mild maceration. Therefore this microbiol complex cannot account for the soft rot also observed in stored fruits. The high frequency of isolation of Cladosporium sp. from disease tissues and bioassay on pear fruit surface suggest that Cladosporium sp. could be a major pathogen in the microbial complex associated with skin sooty dapple disease of the Asian pear in Korea.
Incidences of Leaf Spots and Blights on Kiwifruit in Korea
Jeong, In-Ho ; Lim, Myoung-Taek ; Kim, Gyung-Hee ; Han, Tae-Woong ; Kim, Hong-Chul ; Kim, Min-Ji ; Park, Hyun-Su ; Shin, Soon-Ho ; Hur, Jae-Seoun ; Shin, Jong-Sup ; Koh, Young-Jin ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 125~130
DOI : 10.5423/PPJ.2008.24.2.125
Various kinds of leaf spots and blights were found in kiwifruit (Actinidia deliciosa) orchards on 2006 in Korea. Disease incidences were quite variable between open-field and rain-proof shelter. Rate of diseased leaves was recorded as about 70% at open-field orchards in late season but use of rain-proof vinyl shelters alleviated the disease incidences by 20%. Angular leaf spots appeared at early infection stage on June and several other symptoms were also recognized as the disease developed afterward. On September, brown leaf blights were the most frequent, followed by grayish brown ring spots, silvering gray leaf blights, zonate leaf blights, dark brown ring spots and angular leaf spots at open-field orchards. Four fungal species were frequently isolated from the disease symptoms. Phomopsis sp. was the most predominant fungus associated with the leaf spot and blight symptoms on kiwifruit, followed by Glomerella cingulata, Alternaria alternata and Pestalo-tiopsis sp. Phomopsis sp. was commonly isolated from angular leaf spots, silvering gray leaf blights, and zonate brown leaf blights. G. cingulata, A. alternata and Pestalotiopsis sp. were isolated from grayish brown ring spots (anthracnose), brown ring spots and zonate dark brown leaf blights. Typical symptoms appeared on the wounded and unwounded leaves, which were inoculated by each of Phomopsis sp., G. cingulata, and Pestalotiopsis sp., but A. alternata caused symptoms only on the wounded leaves.
Identification of Genes Encoding Heat Shock Protein 40 Family and the Functional Characterization of Two Hsp40s, MHF16 and MHF21, in Magnaporthe oryzae
Yi, Mi-Hwa ; Lee, Yong-Hwan ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 131~142
DOI : 10.5423/PPJ.2008.24.2.131
Magnaporthe oryzae, the causal agent of the rice blast disease, poses a worldwide threat to stable rice production. The large-scale functional characterization of genes controlling the pathogenicity of M. oryzae is currently under way, but little is known about heat shock protein 40 (Hsp40) function in the rice blast fungus or any other filamentous plant pathogen. We identified 25 genes encoding putative Hsp40s in the genome of M. oryzae using a bioinformatic approach, which we designated M. oryzae heat shock protein forty (MHF 1-25). To elucidate the roles of these genes, we characterized the functions of MHF16 and MHF21, which encode type ill and type n Hsp40 proteins, respectively. MHF16 and MHF21 expression was not significantly induced by heat shock, but it was down-regulated by cold shock. Knockout mutants of these genes
mhf21) were viable, but conidiation was severely reduced. Moreover, sectoring was observed in the
mutant when it was grown on oatmeal agar medium. Conidial germination, appressorium formation, and pathogenicity in rice were not significantly affected in the mutants. The defects in conidiation and colony morphology were fully complemented by reintroduction of wild type MHF16 and MHF21 alleles, respectively. These data indicate that MHF16 and MHF21 play important roles in conidiation in the rice blast fungus.
Virulence Reduction and Differing Regulation of Virulence Genes in rpf Mutants of Xanthomonas oryzae pv. oryzae
Jeong, Kyu-Sik ; Lee, Seung-Eun ; Han, Jong-Woo ; Yang, Seung-Up ; Lee, Byoung-Moo ; Noh, Tae-Hwan ; Cha, Jae-Soon ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 143~151
DOI : 10.5423/PPJ.2008.24.2.143
To define the functions of the rpf genes in Xanthomonas oryzae pv. oryzae (Xoo), which regulates pathogenicity factors in Xanthomonas campestris pv. campestris (Xcc), marker-exchange mutants of each rpf gene were generated. When the mutants were inoculated on a susceptible cultivar, the lesion lengths caused by the rpfB, rpfC, rpfF, and rpfG mutants were significantly smaller than those caused by the wild type, whereas those caused by the rpfA, rpfD, and rpfI mutants were not. Several virulence determinants, including extracellular polysaccharide (EPS) production, xylanase production, and motility, were significantly decreased in the four mutants. However, the cellulase activity in the mutants was unchanged. Complementation of the rpfB and rpfC mutations restored the virulence and the expression of the virulence determinants. Expression analysis of 14 virulence genes revealed that the expression of genes related to EPS production (gumG and gumM), LPS (xanA, xanB, wxoD, and wxoC), phytase (phyA), xylanase (xynB), lipase (lipA), and motility (pitA) were reduced significantly in the mutants rpfB, rpfC, rpfF, and rpfG. In contrast, the expression of genes related to cellulase (eglxob, clsA), cellobiosidase (cbsA), and iron metabolism (fur) was unchanged. The results of this study clearly show that rpfB, rpfC, rpfF, and rpfG are important for the virulence of Xoo KACC10859, and that virulence genes are regulated differently by the Rpfs.
Isolation and Characterization of Pepper mottle virus Infecting Tomato in Korea
Kim, Mi-Kyeong ; Kwak, Hae-Ryun ; Han, Jung-Heon ; Ko, Sug-Ju ; Lee, Su-Heon ; Park, Jin-Woo ; Jonson, Miranda Gilda ; Kim, Kook-Hyung ; Kim, Jeong-Soo ; Choi, Hong-Soo ; Cha, Byeong-Jin ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 152~158
DOI : 10.5423/PPJ.2008.24.2.152
A peculiar virus-like disease of tomato showing yellow mosaic and necrotic spots on leaves and necrosis on veins, petioles and stems was observed at the Tomato Experimental Station (TES), Buyeo, Chungcheongnamdo, Korea. The disease incidence at TES fields ranged from 21 to 35% infecting different tomato cultivars. For this reason, to identify the virus infecting tomato and to characterize the virus based on biology, serology, cytology and at molecular level. Here, leaf samples were randomly collected from different infected tomato cultivars at TES fields and greenhouses and tested by ELISA using Pepper mottle virus (PePMoV) and Tomato mosaic virus (ToMV) antisera. Infected saps were mechanically inoculated in different host plants to test for pathogenicity, symptomatology and host ranges. Infected tissues and ultrathin sections were examined by electron microscopy. Finally, putative coat protein and 3`-untranslated region (CP/3`-UTR) fragment was amplified and cloned for sequence determination and analyzed its genetic relationship to existing PepMoV and PVY sequences at the Genbank. Results showed 69% of the samples were positive with PepMoV, 13% with ToMV and 19 % were doubly infected with PepMoV and ToMV. Symptoms greatly varied from different host plants inoculated with tomato leaf sap infected with PepMoV alone and discussed in detailed in this paper. Electron microscopy from infected tissues showed filamentous particles of 720-750nm in length, a typical morphology and size of PepMoV. In addition, cylindrical inclusion bodies, pinwheels, scrolls and laminates with masses of fibrillar inclusions were also found in ultrathin sections. Alignment of the sequences of the CP/3`-UTR revealed >96% sequence identity with PepMoV and only <61% with PVY. Taken together, all these evidences presented clearly indicated that the causal agent infecting tomato at TES was PepMoV and we designated this PepMoV infecting tomato as Tom-sd2 strain in this study.
A Simple PCR-RFLP for Idenficiation of Bursaphelenchus spp. Collected from Korea
Han, Hye-Rim ; Han, Bo-Young ; Chung, Yeong-Jin ; Shin, Sang-Chul ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 159~163
DOI : 10.5423/PPJ.2008.24.2.159
Accurate identification of pine wood nematode, Bursaphelenchus xylophilus is a prerequisite to diagnose the pine wilt disease. However, a fungivorous nematode, B. mucronatus is highly similar to B. xylophilus and it is difficult to differentiate these two species by morphological features. A molecular diagnosis method, ITSRFLP was applied for the identification of B. xylophilus and B. mucronatus from Korea. Genomic DNA was extracted from a single individual nematode and ITS DNA was amplified by PCR. The size of PCR product was approximately 900bp and the sequence data were obtained after cloning. Amplified ITS was digested by 5 different restriction enzymes (Rsa I, Hae III, Msp I, Hinf I, and Alu I) and provided a discriminatory profile for B. xylophilus and B. mucronatus. Besides, B. mucro- natus was determined to have 2 different genotypes, East Asian type and European type also clearly separated by Rsa I and Hae III digestion. European type of B. mucronatus is recently collected from Pinus koraiensis and has not been reported before. ITS sequnce data were analyzed by Restriction Mapper program and the result supported ITS-RFLP pattern. These data indicated that PCRRFLP method is an accurate and simple way for identification of Bursaphelenchus species.
Enhancement of Biocontrol Activity of Antagonistic Chryseobacterium Strain KJ1R5 by Adding Carbon Sources against Phytophthora capsici
Kim, Yu-Seok ; Jang, Bo-Ra ; Chung, Ill-Min ; Sang, Mee-Kyung ; Ku, Han-Mo ; Kim, Ki-Deok ; Chun, Se-Chul ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 164~170
DOI : 10.5423/PPJ.2008.24.2.164
Carbon utilization by Chryseobacterium strain KJ1R5 was studied to enhance its biocontrol activity against Phytophthora capsid. Chryseobacterium strain KJ1R5 has previously been shown to control Phytophthora blight of pepper (Capsicum annuum L.). Strain KJ1R5 could utilize carbon sources such as L-arabinose, D-cellobiose,
and D-galactose well. P. capsici could utilize D-glucose well, showing the absorbencies ranged from 0.577 to 0.767 at 600nm. When 2% L-arabinose, which could only be utilized by the bio-control strain KJ1R5, was amended into the bacterial suspension, the efficacy of biological control increased. Among the amendments of various carbon sources into bacterial suspension, L-arabinose and D-(+)-glucose significantly enhanced biological control activity, resulting in a reduction of disease incidence to 6.9%, compared to 21.9% for the strain KJ1R5 alone and 81.3% for P. capsici inoculation alone, indicating that amendment with specific carbon sources could increase the biological control activity.
Enhanced Onion Resistance against Stemphylium Leaf Blight Disease, Caused by Stemphylium vesicarium, by Di-potassium Phosphate and Benzothiadiazole Treatments
Kamal, Abo-Elyousr A.M. ; Mohamed, Hussein M.A. ; Aly, Allam A.D. ; Mohamed, Hassan A.H. ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 171~177
DOI : 10.5423/PPJ.2008.24.2.171
In this study, we investigated the induced defense response and protective effects against Stemphylium vesicarium by application of benzothiadiazole (
) and di-potassium phosphate salt
to onion. Onion leaves were sprayed with
, then inoculated 2 days later with a virulent strain of S. vesicarium under greenhouse conditions. Disease severity and activities of peroxidase (PO), polyphenoloxidase, phenylalanine ammonia-lyase (PAL) and phenol contents were evaluated in the treated leaf tissues. Reduction in the disease severity was observed in plants treated with
. Onion plants treated with
and inoculated with the pathogen showed significantly higher PAL activity, PO activity, and phenol contents than inoculated water-treated plants 2 days after the treatment. In conclusion, the results of this study provide evidence that application of simple non-toxic chemical solutions as di-potassium phosphate and
can control Stemphylium leaf blight of onion.
Nematocidal Screening of Essential Oils and Herbal Extracts against Bursaphelenchus xylophilus
Elbadri, Gamal A.A. ; Lee, Dong-Woon ; Park, Jung-Chan ; Yu, Hwang-Bin ; Choo, Ho-Yul ; Lee, Sang-Myeong ; Lim, Tae-Heon ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 178~182
DOI : 10.5423/PPJ.2008.24.2.178
Five essential oils and 15 herbal extracts were evaluated to control Bursaphelenchus xylophillus in laboratory. The essential oils from clove plant (Syzygium aromaticum), mustard (Brassica integrefolia), thyme (Thymus vulgaris), and Pelargonium inquinans were found to be highly promising and gave excellent control of the nematodes at all the time of exposure. Among them, the least one gave 91.3% mean mortality rate at 24 hours of exposure time, which is highly significant from the control. While in the second study, most of the methanol (Desmodium caudatum, Paulownia coreana, Auckulandia lappa, Sophota flavescens, Aloe sp., Rheum palmatum, Zingiber officinale, Magnolia officinalis, and Eugenia caryophyllata), hexane (Torreya nucifera, Pharbitis nil, Prunus mume, Melia azedarach, and Xanthium strumarium), and hot water (Cinnamomum cassia) herbal extracts killed the nematodes, but in varying degrees compared to the control. Only one extract was found to be promising viz Magnolia officinalis which found to be statistically different from the control and gave mean mortality of 72, 82.3, and 85.3 % for 24, 48, and 72 hours exposure, respectively. Further screening was conducted for M. officinalis with concentrations of 1,000, 100, and 10 ppm against the same species of nematode with the same time of exposure. However, it gave an excellent result for 1,000 ppm for all time of exposure, whereas for the 100 and 10 ppm it gave mean mortality of 39.5 and 25.8% for the time 72hrs, respectively that were statistically different from the control.
Disease-resistant Transgenic Arabidopsis Carrying the expI Gene from Pectobacterium carotovorum subsp. carotovorum SL940
Lee, Joo-Hee ; Hong, Ja-Bin ; Hong, Sang-Bin ; Choi, Min-Seon ; Jeong, Ki-Yong ; Park, Hyoung-Joon ; Hwang, Duk-Ju ; Lee, Seung-Don ; Ra, Dong-Soo ; Heu, Sung-Gi ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 183~190
DOI : 10.5423/PPJ.2008.24.2.183
Plant-cell-wall-degrading enzymes (PCWDEs) of Pectobacterium carotovorum subsp. carotovorum are the key virulence factor in pathogenesis of soft rot disease of vegetables. The production of PCWDEs is controlled in a cell density dependent manner to avoid the premature production of PCWDEs and subsequent activation of plant defense. N-oxoacyl-homoserine lactone (OHL) is essential for quorum sensing in the soft rot pathogen and the expI gene is responsible for OHL production. The ExpI homolog isolated from P. carotovorum subsp. carotovorum SL940 had 94% identity with ExpI of E. carotovora subsp. carotovora scc3193 and 74% identity with Carl of E. carotovora subsp. atroseptica. The transgenic plants that express exp I uner the control of CaMV35S promoter were able to produce diffusible OHL. Transgenic plants producing OHL were very resistant to the infection of P. carotovorum subsp. carotovorum. Since the PR1 gene was strongly induced and NPR1 and NPR4 were induced weakly in transgenic plants compared to the wild type, salicylic acid-dependent pathways is likely involved in the resistance to the soft rot pathogen P. carotovorum subsp. carotovorum in ExpI transgenic plants.
Differential Proteomic Analysis of Secreted Proteins from Cutinase-producing Bacillus sp. SB-007
Ban, Yeon-Hee ; Jeon, Mi-Ri ; Yoon, Ji-Hee ; Park, Jae-Min ; Um, Hyun-Ju ; Kim, Dae-Soon ; Jung, Seung-Ki ; Kim, Keun-Young ; Lee, Jee-Won ; Min, Ji-Ho ; Kim, Yang-Hoon ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 191~201
DOI : 10.5423/PPJ.2008.24.2.191
Bacillus sp. SB-007 was isolated from pea leaves harvested from the southwestern parts of South Korea through screening on a minimal medium containing 0.2% purified cutin for its ability to induce the cutinase production. However, no cutinase was produced when it was grown in a minimal medium containing 0.2% glucose. A proteomic approach was applied to separate and characterize these differentially secreted proteins. The expression level of 83 extracellular proteins of the cutinase-producing Bacillus sp. strain SB-007 incubated in a cutinase-induced medium increased significantly as compared with that cultured in a non cutinase-induced medium containing glucose. The extracellular proteome of Bacillus sp. SB-007 includes proteins from different functional classes, such as enzymes for the degradation of various macromolecules, proteins involved in energy metabolism, sporulation, transport/binding proteins and lipoproteins, stress inducible proteins, several cellular molecule biosynthetic pathways and catabolism, and some proteins with an as yet unknown function. In addition, the two protein spots showed little similarities with the known lipolytic enzymes in the database. These secreted proteome analysis results are expected to be useful in improving the Bacillus strains for the production of industrial cutinases.
Antifungal Activity of Lichen-forming Fungi against Colletotrichum acutatum on Hot Pepper
Wei, Xinli ; Jeon, Hae-Sook ; Han, Keon-Seon ; Koh, Young-Jin ; Hur, Jae-Seoun ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 202~206
DOI : 10.5423/PPJ.2008.24.2.202
Antifungal activity of Korean and Chinese lichen-forming fungi (LFF) was evaluated against plant pathogenic fungus of Colletotrichum acutatum, causal agent of anthracnose on hot pepper. This is the first attempt to evaluate antifungal activity of LFF, instead of lichen thalli, against C. acutatum. Total 100 LFF were isolated from the lichens with discharged spore method or tissue culture method. Among the 100 isolates, 8 LFF showed more than 50% of inhibition rates of mycelial growth of the target pathogen. Especially, Lecanora argentata was highly effective in inhibition of mycelial growth of C. accutatum at the rate of 68%. Antifungal activity of other LFF was in the order of Cetrelia japonica (61.4%), Ramalina conduplicans (59.5%), Umbilicaria esculenta (59.5%), Ramalina litoralis (56.7%), Cetrelia braunsiana (56.5%), Nephromopsis pallescensn (56.1%), and Parmelia simplicior (53.8%). Among the tested LFF, 61 isolates of LFF exhibited moderate antifungal activity against the target pathogen at the inhibition rates from 30 to 50%. Antifungal activity of the LFF against C. acutatum was variable at the species level rather than genus level of LFF. This study suggests that LFF can be served as a promising bioresource to develop novel biofungicides.
First Description of Crown Gall Disease on Ginseng
Jeon, Yong-Ho ; Park, Hoon ; Lee, Byeong-Dae ; Yu, Yun-Hyun ; Chang, Sung-Pae ; Kim, Sang-Gyu ; Hwang, In-Gyu ; Kim, Young-Ho ;
The Plant Pathology Journal, volume 24, issue 2, 2008, Pages 207~210
DOI : 10.5423/PPJ.2008.24.2.207
In March of 2003, tumors (galls) were observed on ginseng seedling roots in ginseng seedbeds at Yeoju, Gyeonggi province, Korea. Symptoms were spherical or galls with about 0.5-1.0cm in diameter formed on the upper through middle parts of the primary roots. Bacterial isolates obtained from the root galls were Gram-negative, rod-shaped with peritrichous flagella, aerobic, not forming yellow or orange colonies on nutrient glucose agar, yeast extract-dextrose
agar and nutrient-broth yeast extract agar, non-fluorescent on King`s B agar, and non-spore forming, which were identical to characteristics of the genus Agrobacterium. They were identified as Agrobacterium tumefaciens with 0.732-0.993 similarities in 100% probability by the Biolog analyses. The 16S rRNA gene partial sequences of the six isolates tested (Genbank Accession EF486308-EF486313) were 100% homologous to those of other A. tumefaciens strains (GenBank accession AF501343, AY701900, AY701898, AY701899). The above results confirmed that this bacterium is A. tumefaciens. Pathogenicity of the bacteria was proved by the inoculation test on carrot root discs and tomato seedlings. This is the first description of A. tumefaciens causing root gall in ginseng seedling. The disease occurred locally and sparsely, but considering its appearances in seedbeds suggests that the ginseng root gall may become a threat to ginseng in Korea.