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The Gram-stain-negative, yellow-pigmented, rod-shaped bacterial strain GSE06T, isolated from the surface-sterilized root of a cucumber plant grown in a field in Gunsan, Korea, was characterized by not only cultural and morphological features but also physiological, biochemical and molecular analyses. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain GSE06T was most closely related to species of the genus Chryseobacterium . Furthermore, strain GSE06T exhibited the highest sequence similarities with the type strains Chryseobacterium indologenes ATCC 29897T (98.9 %), Chryseobacterium gleum ATCC 35910T (98.8 %), Chryseobacterium arthrosphaerae CC-VM-7T (98.7 %), Chryseobacterium contaminans C26T (98.5 %), Chryseobacterium artocarpi UTM-3T (98.3 %), and Chryseobacterium gallinarum 100T (97.9 %). Average nucleotide identity values between genome sequences of strain GSE06T and the above-mentioned reference strains ranged from 81.2 to 86.9 %, which were lower than the threshold of 95 % (corresponding to a DNA–DNA reassociation value of 70 %). The DNA G+C content of strain GSE06T was 36.1 mol%; the predominant respiratory quinone of the strain was MK-6. The major fatty acids were iso-C15 : 0, summed feature 9 (iso-C17 : 1ω9c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and iso-C17 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, three aminolipids, one aminophospholipid, four glycolipids and one unidentified lipid. These results of phenotypic and genotypic characteristics could differentiate strain GSE06T from closely related type strains belonging to the genus Chryseobacterium . Thus, strain GSE06T is proposed as a representative of a novel species in the genus Chryseobacterium, Chryseobacterium cucumeris sp. nov. The type strain is GSE06T (=KACC 18798T=JCM 31422T).

Genetically modified (GM) plants have potential benefits in modern agriculture such as increasing yields and decreasing the use of chemicals. However, GM plants may cause unintended consequences of gene flow to indigenous plants or microbes and the detrimental effects on non-target organisms such as soil microbial communities. To investigate these possible unintended effects of GM plants, we conducted a 3-year field study using the transgenic pepper line H-15 carrying the coat protein gene (CMVP0-CP) of Cucumber mosaic virus (CMV) pathotype CMVP0, which is resistant to two CMV pathotypes CMVP0 and CMVP1, to assess its effects on soil fungal populations and communities. This study was conducted in two different fields using the plate counting method on selective media as well as polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis analyses. In addition, we examined potential gene flow of CMVP0-CP from the transgenic line H-15 into the soil environment, including microflora, in the tested fields. We found little differences in the influence of the line H-15 compared with the inbred line P2377 (non-transgenic control) on the populations of fungal groups (total fungi, Aspergillus and Penicillium spp., Fusarium spp., and Trichoderma spp.), distribution of fungal genera, and fungal communities. Further, coat protein gene (CMVP0-CP) (PCR detection limit in soil = 1–10 pg) of the transgenic line was not detected in the soil samples of the tested fields. Taken together, the transgenic pepper line had no distinct impact on fungal populations and communities with no detection of CMVP0-CP gene flow from the transgenic line into the soil environment of the fields. Thus, the transgenic line H-15 might be little significantly harmful from the perspective of preserving soil fungal diversity; it could be a potential candidate for developing a commercial cultivar.

Garlic (Allium sativum L.) is one of the oldest horticultural crops and an important element for cuisines worldwide, especially in Korea. After isolating several black aspergilli from brownish lesions with black spores on garlic bulbs, we identified a representative isolate GL-125 through molecular analysis of its internal transcribed spacer (ITS)1-5.8S rRNA-ITS2 region, β-tubulin gene, and calmodulin gene. Morphological features of GL-125 were also compared with those of the Aspergillus awamori type strain NRRL 4948T. As a result, GL-125 was identified as A. awamori by neighbor-joining and maximum-likelihood methods with the examined gene sequences. The macro-morphological (colony growth and color) and micro-morphological (stripes, vesicles, metulae, phialides, and conidia) features of GL-125 were also similar, compared with those of NRRL 4849T. Furthermore, we conducted pathogenicity tests for GL-125 and NRRL 4948T against garlic cloves, using pin-prick inoculation with spore suspensions. Both GL-125 and NRRL 4948T were pathogenic on garlic cloves producing brown to pinkish sunken, water-soaking lesions with white mycelia and black spores in the center. These isolates were successfully re-isolated from the lesions, thereby fulfilling Koch's postulates, whereas no fungal mycelia were isolated from water-inoculated cloves (control). The identities of the re-isolated mycelia were re-confirmed by sequence analyses of the previously examined genes. To the best of our knowledge, this is the first report of A. awamori as a fungal pathogen of garlic.

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most important bacterial diseases of citrus. Because citrus canker is not found in many countries including European Union and Australia, Xcc is strictly regulated in order to prevent its spread. In this study, the effects of X-irradiation on Xcc growth either in the suspension or on the surface of citrus fruits were investigated. The suspension containing 1×10(7) cfu/ml of Xcc was irradiated with different absorbed doses of X-irradiation ranging from 50 to 400 Gy. The results showed that Xcc was fully dead at 400 Gy of X-irradiation. To determine the effect of X-irradiation on quarantine, the Xcc-inoculated citrus fruits were irradiated with different X-ray doses at which Xcc was completely inhibited by an irradiation dose of 250 Gy. The D10 value for Xcc on citrus fruits was found to be 97 Gy, indicating the possibility of direct application on citrus quarantine without any side sterilizer. Beside, presence of Xcc on the surface of asymptomatic citrus fruits obtained from citrus canker-infected orchards was noted. It indicated that the exporting citrus fruits need any treatment so that Xcc on the citrus fruits should be completely eliminated. Based on these results, ionizing radiation can be considered as an alternative method of eradicating Xcc for export of citrus fruits.

Chryseobacterium sp. strain ISE14 is a phosphate-solubilizing endophytic bacterium that exhibits plant growth promotion and biocontrol activities against Phytophthora blight and anthracnose on pepper., Chryseobacterium sp. strain ISE14 is a phosphate-solubilizing endophytic bacterium that exhibits plant growth promotion and biocontrol activities against Phytophthora blight and anthracnose on pepper. Here, we report the draft genome sequence of strain ISE14, which contains genes relating to phosphate solubilization, plant growth promotion, and biocontrol traits.

Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15 from stored rice grains exhibited antifungal activity against Aspergillus and Penicillium spp. predominant in stored rice. Here, we report their bacterial draft genomes, which contain genes related to biotic and abiotic stress management, as well as antimicrobial and insecticidal traits.

We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107) among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P < 0.05) reduced Phytophthora blight without influencing rhizosphere microbial populations; they showed similar or better levels of disease suppressions than in metalaxyl treatment in the 2007 and 2009 tests, but not in the 2008 test. In the 2-year plastic house tests, all the selected strains significantly (P < 0.05) reduced anthracnose incidence in at least one of the test years, but their biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit.

Two plant growth-promoting rhizobacteria, Pseudomonas corrugata CCR80 and Chryseobacterium indologenes ISE14, previously reported as suppressive to Phytophthora blight of pepper caused by Phytophthora capsici in the field were selected for use of this study. The effects of the strains on microbial activities, populations, and communities in pepper rhizosphere with or without pathogen inoculation were examined at 40, 80, and 120 days after transplanting (DAT) in the field in 2008 and 2009. To investigate the microbial effects, we used culture-dependent and -independent techniques such as plate counts on selective media, and fluorescein diacetate and denaturing gradient gel electrophoresis (DGGE) analyses. Root treatment with the strains increased total microbial activities in rhizosphere soil compared with controls (untreated, metalaxyl, or Escherichia coli DH5α) over the sampling time regardless of pathogen inoculation; however, microbial activities were greatly decreased in all treatments at 40–80 DAT. The strains also impacted the populations of bacterial and fungal functional groups. Eight fungal species, frequently observed on the medium for total fungi, were identified; these populations were significantly affected by the treatments: three species by metalaxyl, one by strain DH5α, one by strain ISE14, and none by strain CCR80 in both years. The DGGE analysis revealed that the strains affected bacterial and fungal community structure; the test strains increased the bacterial community composition, especially at 80 DAT, but had little effect on fungal community at later DAT. Taken together, strains CCR80 and ISE14 increased microbial activities and community composition, and affected certain microbial populations in the rhizosphere of pepper plants in the field, which might play significant roles in the suppression of Phytophthora blight of pepper.

Chryseobacterium sp. strain GSE06 is a biocontrol endophytic bacterium against the destructive soilborne oomycete Phytophthora capsici, which causes Phytophthora blight of pepper. Here, we present its draft genome sequence, which contains genes related to biocontrol traits, such as colonization, antimicrobial activity, plant growth promotion, and abiotic or biotic stress adaptation.

Strain KJ1R5 of the rhizobacterium Chryseobacterium kwangjuense is an effective biocontrol agent against Phytophthora blight of pepper caused by a destructive soilborne oomycete, Phytophthora capsici . Here, we present the draft genome sequence of strain KJ1R5, which contains genes related to biocontrol, plant growth promotion, and environmental stress adaptation.

In this study, we determined the effect of controlling rice weevils on the mycoflora of stored brown rice by using Anisopteromalus calandrae (Howard), a parasite of the rice weevil. The mycoflora in brown rice with the parasitoid was similar to that without the parasitoid; however, the dominant mold species differed. Without the parasitoid, Aspergillus candidus Link and Penicillium islandicum Sopp were the dominant species, whereas Aspergillus penicilloides Speg. and P. islandicum were dominant when the parasitoid was present. The difference appeared to be due mainly to the difference in the grain moisture content with and without the parasitoid. A. candidus was the dominant species in the communities without the parasitoid and was not observed when the weevils were suppressed. P. islandicum dominated or co-dominated regardless of the presence of the parasitoid which suggested that P. islandicum is tolerant to low grain moisture content or is positively affected by the presence of the rice weevil.

A representative isolate KU53 of the predominant Penicillium species was obtained from rice samples from rice processing complexes of National Agricultural Cooperative Federation in Korea. In this study, isolate KU53 was identified by its morphological and molecular characteristics. The macro- and microscopic characteristics of isolate KU53 were compared with the P. fellutanum reference isolate KCTC16913 on different media; isolate KU53 was generally identical to those of the reference isolate KCTC16913. In a molecular-based identification, the β-tubulin and translation elongation factor 1-alpha sequences of isolate KU53 was most closely related to those of P. fellutanum. Thus, isolate KU53 from stored rice could be identified as P. fellutanum, some isolates of which are known to produce mycotoxin-related metabolites. To our knowledge, this is the first detection of P. fellutanum from stored rice in Korea.

Laboratory of Plant Disease and Biocontrol, Korea University, Seoul 136-713, Korea(Received on March 23, 2011; Accepted on April 17, 2011)During the summer of 2005, specimens of soybean culti-vars (Daepung, Daewon, Hwanggeum and Taegwang)showing frogeye leaf spot (FLS) were obtained fromvarious areas in Korea. Eight isolates identified asCercospora sojina were inoculated on the adaxial leafsurfaces of 63 Korean soybean cultivars; the diseaseresponses to each isolate were evaluated 14 days and 21days after inoculation. Based on the disease responses(resistant or susceptible) of the cultivars by the isolates,a set of cultivars (Anpeong, Bogwang, Cheongdu No. 1,Cheongja No. 3, Dachae, Daemang, Jangwon, Namhae,Sowon, Taegwang) were selected and inoculated withseven isolates for further testing pathogenic variance.Interestingly, 6 out of 7 tested C. sojina isolates revealeddifferential ability in infecting different soybean culti-vars. This result may indicate the possibility of new raceoccurrence or pathogenic variation; this also presentsevidence for prevalent FLS occurrence during humidand hot weather in Korea.Keywords : Cercospora sojina, frogeye leaf spot, soybeancultivarCercospora sojina is the causal agent of frogeye leaf spot(FLS) on soybeans [Glycine max (L.) Merr.]. The pathogencan infect leaves, stems, and seeds of the host plant. Thesymptoms on leaves are circular or angular, and 1−5 mm indiameter. The water soaked and mature symptomatic spotsappear suddenly and develop into brown spots surroundedby a dark reddish brown margin (Hartman et al., 1999).Upon aging of a lesion, the center becomes grey to lightbrown in color and forms conidiophores and conidia.Lesions appear at time intervals and join together to formirregular lesions. When lesions cover about 30% of the totalleaf area, the leaf quickly withers and falls prematurely(Hartman et al., 1999; Phillips and Boerma, 1981), resultingin more than 35% yield loss through a reduction of seedsize during hot, humid weather (Laviolette et al., 1970;Mian et al., 1998; Mwase and Kapooria, 2000; Wrather etal., 2001; Yorinori, 1981). Epidemics and declines of FLS incidence have shownrepeated cycles. New C. sojina races, infecting cultivarsthat are widely grown and resistant to established races,appear; thus, the disease is prevalent. Since a cultivar, that isresistant to a new prevalent race and a previous establishedrace, had been developed, widely grown, the diseaseincidence has been declined (Athow and Probst, 1952;Athow et al., 1962; Phillips and Boerma, 1981; Ross,1968). Many races have been reported worldwide: 12 racesin the USA, 11 races in the People’s Republic of China,more than 20 races in South America and a race in Japan(Hartman et al., 1999). Thus, monitoring C. sojina racesand developing resistant soybean cultivars should beconcerned in widely soybean-producing countries. In Korea, although soybeans have been widely cultivatedand many soybean cultivars are inbred, there has been littleresearch concerning disease response of cultivars against C.sojina. Therefore, the objective of this study was to deter-mine disease responses of ten soybean cultivars to seven C.sojina isolates for race identification in Korea. FLS-diseased leaves of soybean collected from northernGyeonggi, Gangwon, Gyeongsang, and Chungcheong pro-vinces in July to September, 2005 were provided fromGyonggi-do Agricultural Research and Extension Services,Northern Agriculture Research Station, Yeoncheon, Korea.For fungal isolation, single spore was isolated from spotson leaves and cultured on potato dextrose agar (PDA).After incubation of these plates at 25

Sang, M. K., and Kim, K. D. 2011. Biocontrol activity and primed systemic resistance by compost water extracts against anthracnoses of pepper and cucumber. Phytopathology 101:732-740. We investigated direct and indirect effects of compost water extracts (CWEs) from Iljuk-3, Iljuk-7, Shinong-8, and Shinong-9 for the control of anthracnoses caused by Colletotrichum coccodes on pepper and C. orbiculare on cucumber. All tested CWEs significantly (P < 0.05) inhibited in vitro conidial germination and appressorium formation of the fungal pathogens; however, DL-β-amino-n-butyric acid (BABA) failed to inhibit the conidial development of the pathogens. Direct treatments of the CWEs and BABA on pepper and cucumber leaves at 1 and 3 days before or after inoculation significantly (P < 0.05) reduced anthracnose severities; Iljuk-3, Shinong-9, and BABA for pepper and Iljuk-7 for cucumber had more protective activities than curative activities. In addition, root treatment of CWEs suppressed anthracnoses on the plants by the pathogens; however, CWE treatment on lower leaves failed to reduce the diseases on the upper leaves of the plants. The CWE root treatments enhanced not only the expression of the pathogenesis-related (PR) genes CABPR1, CABGLU, CAChi2, CaPR-4, CAPO1, and CaPR-10 in pepper and PR1-1a, PR-2, PR-3, and APOX in cucumber but also the activity of β-1,3-glucanase, chitinase, and peroxidase and the generation of hydrogen peroxide in pepper and cucumber under pathogen-inoculated conditions. However, the CWE treatments failed to induce the plant responses under pathogen-free conditions. These results indicated that the CWEs had direct effects, reducing anthracnoses by C. coccodes on pepper leaves and C. orbiculare on cucumber leaves through protective and curative effects. In addition, CWE root treatments could induce systemic resistance in the primed state against pathogens on plant leaves that enhanced PR gene expression, defense-related enzyme production, and hydrogen peroxide generation rapidly and effectively immediately after pathogen infection. Thus, the CWEs might suppress anthracnoses on leaves of both pepper and cucumber through primed (priming-mediated) systemic resistance.

The efficacy of resistance in tomato plants, induced by rhizobacteria isolated from Jeju Island in Korea, against late blight disease caused by Phytophthora infestans was tested. Among the bacterial isolates tested, pre-inoculation with four isolates induced an effective defense against late blight. The four isolates, TRH423-3, TRH427-2, KRJ502-1 and KRY505-3, were identified as Burkholderia gladioli, Miamiensis avidus, Acinetobacter quenomosp and Bacillus cereus, respectively, by sequencing the ribosomal intergenic spacer region. They also promoted the growth of tomato seedlings. To illustrate resistance mechanisms, the infection process by P. infestans was examined using a fluorescence microscope. There were no noticeable differences in the rate of germination and appressorium formation between the untreated and pre-inoculated plants. However, callose was more frequently formed at the penetration sites on the leaves of pre-inoculated plants than the untreated plants, suggesting that these rhizobacterial isolates induce defense responses against P. infestans.

We evaluated microbial populations and aflatoxin production in unhulled and white rice from rice processing complexes of the National Agricultural Cooperative Federation in five regions in Korea and identified three predominant Aspergillus species. Fungal and bacterial populations in rice samples were significantly different between regions in 2007. Aflatoxins were also detected and varied at the levels of 2.45 - 3.43 ng per g unhulled rice grain and 1.29 - 2.09 ng per g white rice grain. Unhulled rice generally detected higher level of aflatoxins than white rice regardless of sampling regions; however, no significant differences were found in Anseong and Cheonan in 2005 and Cheonan and Gimpo in 2007. Aflatoxin production between sampling regions was not different regardless of rice type and sampling year. Although the fungal diversity was highly distinct from region to region, three Aspergillus isolates were predominant in the rice samples; thus, representative isolates AC317, AF57, and AF8 were selected and identified based on their morphological and molecular characteristics. Consequently, isolates AC317, AF57, and AF8 were identified as A. candidus, A. flavus, and A. fumigatus, respectively. These fungi can produce mycotoxins that are harmful for consumers and thus it is important to detect and reduce the population of storage fungi in rice.

In this study, we characterized the bacterial strain KJ2C12 in relation with its biocontrol activity against Phytophthora capsici on pepper, and identified this strain using morphological, physiological, biochemical, fatty acid methyl ester, and 16S rRNA gene sequence analyses. Strain KJ2C12 significantly (P

We have previously obtained a representative isolate KU101 of the predominant Penicillium species from rice under indoor storage conditions. In this study we attempted to characterize isolate KU101 using its morphological and molecular characteristics. When the micro- and macroscopic characteristics of isolate KU101 were compared with the P. islandicum reference isolate KCCM 34763, isolate KU101 was generally identical to those of isolate KCCM 34763, however, isolate KU101 grew faster and produced more orange to red pigments than isolate KCCM 34763. In a molecular-based identification, the nuclear sequence of the ITS1-5.8S-ITS2 region of isolate KU101 was most closely related to that of P. islandicum. Therefore, these results indicated that isolate KU101 from stored rice could be identified as P. islandicum, some isolates of which are known to produce mycotoxins.

In healthy, untreated pepper plants, transcripts of thionin (CATHION1) gene were induced in an organ-specific manner, as revealed by RNA blot analysis and in situ hybridization. The CATHION1 mRNAs were expressed in stems and flowers as well as roots, but not in leaves and fruits. In the stem and root tissues, the CATHION1 mRNA was present in endodermis and the phloem. In contrast, the transcripts were uniformly located in all the cells of flower tissues. Northern blot analysis and in situ hybridization were also performed to examine the temporal and spatial expression patterns of thionin (CATHION1) mRNA in leaf and fruit tissues of pepper (Capsicum annuum L.) infected by anthracnose pathogens Colletotrichum coccodes and C. gloeosporioides, respectively. Transcripts of the CATHION1 gene were more rapidly induced in pepper leaves at the 4- than at the 8-leaf stage by C. coccodes infection. Typical anthracnose symptoms were observed on green pepper fruits inoculated with C. gloeosporioides, but not on red pepper fruits. The transcript accumulation was more pronounced in green fruits than in red fruits upon C. gloeosporioides infection. The CATHION1 transcripts were detected in the phloem cells infected by anthracnose pathogens.

This research was conducted to evaluate fungal and bacterial populations in unhulled and brown rice under indoor storage conditions, and to examine the relationship between microbial populations and environmental conditions such as temperature and relative humidity. The temperature and relative humidity of the storage room ranged from and 23.3% to 44.2%, respectively. Total fungal and bacterial populations remained relatively stable over the storage period. Predominant fungi included Aspergillus candidus, A. flavus, A. fumigatus, and Penicillium spp.; the predominant bacteria were Bacillus, Microbacterium, Sphingomonas, and Methylobacterium spp. Total fungi and bacteria were not significantly correlated with either unhulled (r

Functional Analyses of Three Gα and One Gβ Subunits in Gibberella zeaeComparison between Wild Strains of Pitoporus betulinus Collected from a Single TreeEcological Study of Sparassis crispa in Gwan...

A method was developed using scanned computer images and software programs to measure the lesion area on leaves with cucumber anthracnose caused by Colletotrichum orbiculare. After cucumber plants were inoculated with various concentrations of conidia, lesions on diseased leaves were scanned, manipulated with Adobe Photoshop 6.0, and measured using the blob analysis feature in Matrox Inspector 2.2. The method requires relatively low-cost equipment including a scanner, a personal computer, and two programs: Adobe Photoshop 6.0 and Matrox Inspector 2.2. Because stored images are used, the lesion area can be measured as time permits. Processing the images requires about 3 min per sample. The image assessment accurately detected anthracnose lesions on cucumber leaves and could be applied to other foliar necrotic or spot diseases.

Colletotrichum gloeosporioides isolate KG13 caused necrotic, sunken anthracnose symptoms on unwounded, wax-removed, and wounded green pepper fruits and on wounded red fruits 7 days after inoculation. Hypersensitive reactions with small brownish discolorations, on some occasions, were found on unwounded red fruits. The isolate produced whitish symptoms with brown margins, but not the typical anthracnose on red fruits wax-removed by chloroform treatment. Generally, wax-removed red fruits, but not green ones, produced larger lesions and more conidia than untreated controls. Wounded pepper fruits had larger lesions than those with other treatments. More germinated conidia, appressoria, and infection hyphae were found on wax-removed fruits than on controls; however, differences between green and red fruits were not found. Cuticular wax layers of fruits were dissolved partially by chloroform and the outer epidermal cells were disrupted slightly. Anthracnose development was negatively related with fruit developmental stage. Well-developed fruits had more cuticular wax than less developed fruits. These results suggest that the cuticular wax layers of pepper fruits may play a significant role in fruit infection by C. gloeosporioides isolate KG13, and mainly determine the incompatibility of red fruits to the isolate. Biochemical differences may also play a role. Zusammenfassung Bedeutung der kutikularen Wachsschichten gruner und roter Paprikaschoten fur die Infektion mit Colletotrichum gloesporiodes Das Isolat KG13 von Colletotrichum gloeosporioides rief bei unverletzten grunen Paprikaschoten, deren Wachsschicht entfernt worden war, bei verletzten grunen Paprikaschoten und bei verletzten roten Paprikaschoten 7 Tage nach der Inokulation nektrotische, eingesunken Brennflecken hervor. Bei einigen unverletzten roten Schoten traten Hypersensitivitatsreaktionen auf, die sich als kleine braunliche Verfarbungen zeigten. Bei roten Fruchten, deren Wachsschicht durch eine Chloroformbehandlung entfernt worden war, rief das Isolat weisliche Lasionen mit braunem Rand, aber keine typischen Brennflecken hervor. Bei den roten Fruchten, deren Wachsschicht entfernt worden war, waren die Lasionen allgemein groser und die Konidien zahlreicher als bei den unbehandelten Kontrollen; bei den grunen Fruchten war dies nicht der Fall. Bei verletzten Paprikafruchten warendie Lasionen groser als bei den anders behandelten Schoten. Auf den Fruchten, deren Wachsschicht entfernt worden war, fanden sich im Vergleich zu den Kontrollen mehr gekeimte Konidien, mehr Appressorien und mehr Infektionshyphen; Unterschiede zwischen grunen und roten Paprikaschoten waren dabei nicht feststellbar. Die kutikularen Wachsschichten der Fruchte wurden durch Chloroform teilweise entfernt, wahrend die auseren Epidermiszellen mechanisch leicht verletzt wurden. Die Entwicklung der Brennfleckenkrankheit war mit dem Entwicklungsstadium der Paprikaschoten negativ korreliert. Gut entwickelte Fruchte besaszen mehr kutikulares Wachs als weniger entwickelte. Diese Ergebnisse legen nahe, das die kutikularen Wachsschichten von Paprikaschoten grose Bedeutung fur die Infektion der Schoten durch das Isolat KG13 von C. gloeosporioides haben und masgeblich fur die Inkompatibilitat roter Schoten fur das Isolat verantwortlich sein konnten. Auch biochemische Unterschiede spielen hier moglicherweise eine Rolle.

Stored rice was collected from rice processing complexes of National Agricultural Cooperative Federation of 11 regions in Korea to evaluate the occurrence of fungi and bacteria and to identify the predominant fungi and bacteria to the genus levels. Most rice samples generally produced the higher levels of fungi and bacteria than white rice. The occurrence of fungi and bacteria varied in various locations of Korea. Among fungi observed, Aspergillus spp. and Penicillium spp. were dominant in the samples and Aspergillus spp. were observed more frequently than Penicillium spp. Predominant bacteria from rice and white rice samples tentatively belonged to the Genus Bacillus, Pectobacterium, Pantoea, and Microbacterium according to BIOLOG and FAME analyses. The results of this study showed that rice in Korea was contaminated in a relatively high level by two dominant storage fungi such as Aspergillus spp. and Penicillium spp. In addition, occurrence of mycotoxins in rice by the fungi could be possible and thus it is necessary to control the storage fungi.

Importing citrus fruits infected by Asiatic citrus canker caused by Xanthomonas citri pv. citri (Xcc) can act as an inoculum source for the disease epidemic in citrus canker-free countries. In this study, the pathogenicity of the causal agent of Asiatic citrus canker surviving on infected Satsuma mandarin fruits was evaluated. The washing solution of infected Satsuma mandarin fruits did not cause lesion formation on the citrus leaves. However, a typical citrus canker lesion was formed on the leaves after inoculation with higher concentrations of the inoculum from the washing solution (washing solution II). It indicated that the pathogenicity of the citrus canker surviving on the symptomatic Satsuma mandarin fruits was not changed. Scanning electron microscopic observation showed that the numbers of bacterial cells on the leaves of Satsuma mandarin which inoculated with the washing solution directly (washing solution I) was less compared to those of leaves inoculated with the washing solution II. This result spports that the pathogenicity of Xcc surviving on Satsuma mandarin fruits may not be changed but that the sucessful infection of citrus caker may depend on the concentration of the inoculum.

The yellow-pigmented, Gram-stain-negative, rod-shaped bacterium KJ1R5T was isolated from the root of a pepper plant grown in a field in Kwangju, Korea. Strain KJ1R5T was characterized by physiological, biochemical, and molecular genetic analyses. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain KJ1R5T was most closely related to members of the genus Chryseobacterium , and that the strain exhibited the highest similarities with type strains of Chryseobacterium vrystaatense (97.0 %) and Chryseobacterium rhizosphaerae (97.1 %). DNA–DNA hybridization reassociation values between strain KJ1R5T and type strains of C. vrystaatense KACC 11675T and C. rhizosphaerae KACC 14918T were 46.9 and 38.4 %, respectively. The DNA G+C content of KJ1R5T is 40.2 mol%. The predominant respiratory quinone of KJ1R5T was menaquinone MK-6; major cellular fatty acids were iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C17 : 1ω9c, and iso-C17 : 0 3-OH. On the basis of these phenotypic and genotypic characteristics, the strain significantly differed from representative strains belonging to the genus Chryseobacterium . Thus, we propose that strain KJ1R5T represents a novel species of the genus Chryseobacterium , named Chryseobacterium kwangjuense sp. nov. The type strain is KJ1R5T ( = KACC 13029T = JCM 15904T).

Sectors of rice blast fungus, Pyricularia grisea, frequently appeared on potato dextrose agar amended with edifenphos and iprobenfos. Thus, we assessed the sector-forming frequency of isolates of P. grisea and compared the fungicide sensitivity between wild types and sectors against the fungicides. The 905 isolates of the fungus were obtained from rice-growing locations in Korea from 1997-1998. When the isolates were grown on potato dextrose agar amended with minimal inhibitory concentrations of edifenphos (20 g a.i./ml)and iprobenfos (55 g a.i./ml), they produced sectors that overcame the effect of the fungicides. Among the 905 isolates tested, 9.0% produced sectors against edifenphos and 5.6%, against iprobenfos. Different sector-forming frequencies were also observed among the 11 locations of Korea. Sectors obtained from the fungicide-amended media generally grew more than their counterpart wild types grown on the media with either edifenphos or iprobenfos, regardless of their origins. In this study, greater relative growth of sectors over wild types of tested isolates can support the resistant characteristic of the fungus to survive against the fungicides. Therefore, the results indicate that the sectoring in rice blast fungus, P. grisea, may play a role in the occurrence of fungicide resistance.

A pepper gene, CABPR1, which encodes basic pathogenesis-related protein 1, has been reported to be strongly induced after ethephon treatment, wounding, and tobacco mosaic virus infection. The potential role of CABPR1 in tolerance of biotic or abiotic stresses was examined in transgenic Nicotiana tabacum cv. xanthi plants. Overexpression of CABPR1 in tobacco plants enhanced tolerance not only to heavy metal stresses, but also to the oomycete pathogen Phytophthora nicotianae, and the bacterial pathogens Ralstonia solanacearum and Pseudomonas syringae pv. tabaci. RT-PCR revealed that the CABPR1 transgene increased expression of the PR-Q and glutathione S-transferase genes, but decreased expression of the PR-1a and thaumatin genes. Moreover, these transgenic lines exhibited significant decreases in total peroxidase activity and transcription level, suggesting that overexpression of CABPR1 in tobacco cells altered the balance of redox systems. Redox imbalance in transgenic lines may lead to H(2)O(2) accumulation, triggering tolerance to biotic and abiotic stresses.

To select active bacterial strains to control plant diseases, 57 bacterial strains were isolated from the rhizosphere of the plants growing in various areas such as coast, middle and top of Halla M...

Six rice cultivars showing various types of resistance or susceptibility to Pyricularia oryzae in the field were compared under controlled environmental conditions. The resistance of the cultivars with adult-plant resistance was race-specificat early growth stage. On all cultivars tested, blast infection became increasingly reduced on either leaves of adult plants or older leaves, as observed in rice plants of different leaf stages infected with different individual races. Their increase inhost resistance was marked by an apparent transition in infection type and reduced blast severity depending on leaf age and developmental stage of plants. The ranking of disease severity of the adult-plantresistant cultivars to different races was constant during plant development, whereas that of the susceptible cultivars was differential. It is suggested that different degrees of resistance in rice cultivars may exist in seedlings and be consistently maintained during plant development, probably becoming more distinct as rice plants mature.