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1.
Symptoms of brown blotch were observed on cultivated Agaricus bisporus on several mushroom farms in Serbia. Subsequently, samples were collected from nine localities during 2006?C2010 and fluorescent Gram-negative bacterial strains were isolated. All strains caused sunken brown lesions on A. bisporus tissue blocks after artificial inoculation. Isolated strains showed the LOPAT characteristics of the group Va being negative for levan production; the ability to produce a hypersensitivity reaction in tobacco; were oxidase and arginine dihydrolase positive; and lacked pectolytic activity. The results from other tests were as follows: oxidative metabolism of glucose; catalase activity positive; aesculin hydrolisis negative; Tween 80 hydrolysis positive; casein hydrolysis positive; gelatine hydrolysis and nitrate reduction negative; mannitol, erythritol, sorbitol, inositol and trehalose were used as a carbon source but not sucrose, arabinose and D(-) tartrate. Based on these features bacterial strains were identified as Pseudomonas tolaasii. The identity of isolated strains was confirmed by polymerase chain reaction. This is the first report of P. tolaasii in Serbia.  相似文献   

2.
Bacterial brown blotch disease, caused by Pseudomonas tolaasii, has been one of the most serious bacterial diseases of the oyster mushroom. Resistance to disease has been a priority in breeding programs for the oyster mushroom. In this study, a set of 37 Pleurotus ostreatus strains was tested for resistance to the pathogen P. tolaasii by two methods, with inoculations on pileus and spawned substrate under controlled environmental conditions. The results showed that the protocol with inoculation on spawned substrate was sensitive and adequate for testing resistance of oyster mushroom to brown blotch disease. According to the disease severity of fruiting bodies with inoculation on spawned substrates, strain ACCC50618 was resistant; ACCC50236 was moderate resistant; and the others were susceptible to the pathogen P. tolaasii (ACCC 01267). However, it was difficult to differentiate the resistance of P. ostreatus strains to P. tolaasii by inoculation on the pileus. This is the first report about resistance evaluation of P. ostreatus to brown blotch disease.  相似文献   

3.
Since 2002, papaya black rot has been spreading over several islands of Okinawa Prefecture, Japan. To devise a prevention strategy for the disease, microbiological research on the pathogen was conducted. Twelve strains were isolated from papaya infected with black rot showing symptoms such as water-soaked lesions on stems and petioles, black spots on fruits, and rotted leaves turning yellow with necrotic spots. Through Koch's postulates, we confirmed that the isolated strains caused papaya black rot. Bacteriological assays showed that the strains have characteristics different from the type strains of Erwinia mallotivora, E. papayae, and E. psidii. Moreover, 16S rDNA sequence similarity searches showed that the isolated strains had less than 98.6% similarity with type strains. Additionally, phylogenetic analysis of 16S rDNA sequences suggested that the isolated strains were possibly a novel species belonging to the genus Erwinia, as the strains formed an independent cluster and had low sequence similarity with the type strains. Earlier studies indicated that papaya black rot is caused by E. cypripedii. Therefore, we propose to add the Erwinia sp. isolated in this study to the list of papaya black rot pathogens.  相似文献   

4.
In October 2010, a bacterial disease produced flecks and spots on leaves of Chinese cabbage, cabbage and Japanese radish in Nagano Prefecture, Japan. The symptoms started on the abaxial surface of leaves as angular, water-soaked flecks of 1–2 mm in diameter with a yellow halo of 3–4 mm width. These flecks then became visible on both leaf surfaces, enlarged and coalesced into large blight lesions. The symptoms were similar to bacterial leaf spot caused by Pseudomonas syringae pv. maculicola. The bacterium isolated from leaf lesions formed a white colony and produced polysaccharides on YP agar. The isolates were identified as P. syringae group by LOPAT tests and the 16S rDNA sequence. Moreover, the results of pathogenicity on cruciferous plants, bacteriological characteristics, rep-PCR and the sequences of rpoD and gyrB showed that the isolates should be identified as P. cannabina pv. alisalensis (recently transferred from P. syringae pv. alisalensis). This is the first report of P. cannabina pv. alisalensis isolated from diseased crucifers in Japan.  相似文献   

5.
In 2008, bacterial rot on onion bulbs (Allium cepa L.) was observed in several low-temperature warehouses in Changnyeong-gun, Korea. The causal pathogen was isolated and identified as Bacillus amyloliquefaciens based on morphological and biochemical characterization and sequence analysis of its genome. The isolated bacteria caused the same rot symptom on inoculated onion bulbs as found in naturally infected onions during storage and was reisolated from these bulbs. This is the first report of bacterial rot of onion caused by B. amyloliquefaciens in Korea.  相似文献   

6.
Sweet peppers (cv. Tosajishi beauty) with leaf blight symptoms were observed in Kochi Prefecture, 2003. Initially, small spots formed on leaves, and later enlarged to brown to dark brown spots, and eventually blighted leaves fell. Several bacteria that caused the same symptoms were isolated and subsequently reisolated. These bacteria were identified as Pseudomonas cichorii on the basis of bacterial characteristics and the 16S rRNA gene sequence. This is the first report of bacterial leaf blight in the sweet pepper in the world.  相似文献   

7.
Essential oils of Matricaria chamommilla, Mentha piperita, M. spicata, Lavandula angusti folia, Ocimum basilicum, Thymus vulgaris, Origanum vulgare, Salvia officinalis, Citrus limon and C. aurantium and their components; linalyl acetate, linalool, limonene, α-pinene, β-pinene, 1,8-cineole, camphor, carvacrol, thymol and menthol were assayed for inhibitory activity against the three major pathogens of the button mushroom, Agaricus bisporus, i.e. the fungi Verticillium fungicola and Trichoderma harzianum and the bacterium Pseudomonas tolaasii. The highest and broadest activity was shown by the Origanum vulgare oil. Carvacrol possessed the highest antifungal activity among the components tested.  相似文献   

8.
为获得对烟草黑胫病有较强生防效果的拮抗细菌,从健康烟草根际采集30份土壤样品,分离纯化得到347株细菌,经病原真菌定向筛选后得到1株对烟草黑胫病菌等病原真菌拮抗活性较好的细菌FB-16,其对烟草黑胫病菌的抑菌带宽为23mm。采用菌丝生长速率法、作用机制试验、温室防病试验测定FB-16的抑菌作用,并通过形态学特征、生理生化特征及16S rDNA序列分析对菌株进行鉴定。结果显示,菌株FB-16发酵液对烟草黑胫病菌菌丝生长抑制率为95.96%;其代谢产物对烟草黑胫病菌菌丝有致畸作用;菌株FB-16为解淀粉芽胞杆菌Bacillus amyloliauefaciens(Gen-Bank登录号为JN245982);饱和度25%硫酸铵获得的抑菌物质对烟草黑胫病菌的抑菌活性较高,抑菌圈直径达42.00 mm;FB-16活性产物处理的烟草植株在接种烟草黑胫病菌7天后的防治效果为69.96%。表明菌株FB-16在烟草黑胫病生物防治中具有潜在的利用价值。  相似文献   

9.
A survey in 1987 and 1988 revealed that basal glume rot, caused by Pseudomonas syringae pv. atrofaciens, occurred nearly everywhere in FRG. The symptoms of the disease usually consisted of water-soaked dark green to brown lesions on unripe wheat heads, mainly at the basal end of the glumes, which later became dark brown. Forty-six isolates of P.s. atrofaciens were obtained from glumes, seeds and leaves of wheat and barley. For a fast identification of the isolated bacteria, a bio-assay was developed. Four to five-day-old wheat seedlings, grown on wet filter paper in Petri dishes, were pricked at two-three sites with a dissecting needle contaminated with bacteria. After 2–3 days, pathogenic isolates induced brown to black spots. The bacterial isolates from wheat inhibited the growth of several fungi grown on potato dextrose agar. In contrast, an authentic isolate of P.s. syringae obtained from wheat showed no inhibitory effect. During screening for resistance, several cultivars of spring and winter wheat were tested in the greenhouse and/or field tests. The results revealed marked differences in the susceptibility of different cultivars.  相似文献   

10.
A bacterial disease of tomato fruits was recorded during the winter in outdoor crops in Crete, causing damage of up to 30% in commercial production. Bacterial spots appeared on the upper surface of middle size immature fruit and the spots became larger with the increase of fruit size. Spots were round or elongated, superficial and lightly sunken, 1.5–2cm in diameter. The centre of the spots dried out and became progressively gray, brown to black-brown and had intensely coloured margins. The infected area did not develop into soft rot. The bacterium Pseudomonas viridiflava (Burkholder) Dowson was identified as the causal agent on the basis of morphological, physiological, biochemical and pathological characters. This appears to be the first time that these symptoms have been described on tomato fruit.  相似文献   

11.
A leaf spot disease was found widespread on Bougainvillea in Brunei Darussalam. Leaf spots were characterized by circular to irregular brown necrotic areas with yellow haloes. A non-fluorescent bacterium was isolated consistently from the lesions and confirmed as the causal agent by Koch's postulates. On the basis of biochemical characterization and inoculation tests, the bacterium was identified as Pseudomonas andropogonis. This is the first report of a bacterial disease on bougainvillea in Brunei Darussalam.  相似文献   

12.
Ewingella americana was identified as the causal agent of internal stipe necrosis on symptomatic samples collected from mushroom farms located in Castilla-La Mancha, Spain, during the years 2008 to 2010. Six isolates obtained from Agaricus bisporus (button mushroom) and Pleurotus ostreatus (oyster mushroom) were studied to gain insight into their diversity. According to their biochemical profile, the isolates corresponded to biogroup 1. RAPD typing was performed directly with broth cultures of bacteria using two selected primers, and the profiles obtained were used to define four RAPD types. The pathogenicity of isolates was tested by artificial inoculation in A. bisporus and P. ostreatus, in both of which the pathogen reproduced the disease symptoms, and was reisolated from inoculated specimens. Artificial inoculations of the bacteria on Pleurotus eryngii (king oyster mushroom) reproduced the symptoms of the disease, but, until now, this bacterium has not been isolated from this fungus.  相似文献   

13.
Gut bacteria of fruit fly, Bactrocera tau (Walker) (Diptera: Tephritidae), were isolated and the isolates attractive to B. tau adults were characterized using morphological, biochemical and 16S rRNA analyses to determine their taxonomic position. Based upon morphological, biochemical and 16S rRNA sequences (on the basis of closest match), five gut bacterial species of B. tau were characterized as Delftia acidovorans, Pseudomonas putida, Flavobacterium sp., Defluvibacter sp. and Ochrobactrum sp., of which four bacterial isolates, viz., Delftia acidovorans, Flavobacterium sp., Defluvibacter sp. and Ochrobactrum sp. are new records from guts of the fruit fly species.  相似文献   

14.
This report is the first of cobweb disease on Agaricus bisporus in Korea. Cobweb on both fruit bodies and casing soils were observed on several mushroom farms in Gyeongbuk Province, Korea. Classical and molecular characterization indicated that the causal agent is Cladobotryum mycophilum. The isolated fungus was used to inoculate fruiting bodies of A. bisporus and caused the same symptoms.  相似文献   

15.
拮抗细菌FD6分离自福建闽侯青口青菜根围土壤,采用凹玻片法和离体叶片接种法测定菌株FD6的抑菌能力,经16S rDNA序列比对和相关生理生化性状分析,对生防细菌FD6进行了鉴定,并通过PCR扩增、薄层层析、薄层色谱生物自显影等探讨FD6产生抗生素的种类及其抑菌效果。结果表明,FD6的细菌悬浮液可显著抑制灰霉病菌分生孢子萌发,抑制率达99%,FD6培养滤液的抑制率仅为31%;细菌悬浮液对番茄灰霉病防效达59.7%。FD6的16S rDNA序列与假单胞菌属Pseudomonas的相似性达99%,系统进化树显示与荧光假单胞菌P.fluorescens遗传距离最近,结合生理生化表型特征将FD6菌株鉴定为荧光假单胞菌P.fluorescens。菌株FD6可产生硝吡咯菌素、2,4-二乙酰基间苯三酚、藤黄绿脓菌素、嗜铁素、氢氰酸和蛋白酶等抗菌物质,不产生吩嗪-1-羧酸,其中,硝吡咯菌素可直接抑制番茄灰霉病菌孢子萌发和菌丝的生长。  相似文献   

16.
In 2014 and 2015, an unknown leaf spot disease was found on tobacco in Guangxi, China. The fungus isolated from these spots was identified as Fusarium proliferatum based on morphological characteristics and sequence analysis of translation elongation factor 1 alpha (tef1α). This fungus also reproduced leaf spot symptoms after inoculation and was reisolated from the symptomatic lesions. This is the first report of a new leaf spot caused by Fusarium proliferatum on tobacco.  相似文献   

17.
Pith necrosis is a common disease of tomato in Europe, mainly caused by Pseudomonas corrugata and other soil-borne species of Pseudomonas. During 2011–2012 a survey was conducted in soil-grown tomato crops in southeastern Sicily (Italy). Plants showed pith necrosis, brown discolouration of the vascular tissues, leaf chlorosis and sometimes wilting of leaves. Thirty bacterial isolates from symptomatic tissues, forming colonies on NA and KB, were identified by morphological, biochemical and physiological tests. Among them, seven isolates were analyzed for their 16S rDNA and 16S–23S spacer region sequence that resulted in 99 % identity to that of the Xanthomonas perforans type strain (GenBank accession number GQ46173over 2.085 bp.). Additional sequences of fusA, gapA, gltA, gyrB, lacF, and lepA from one selected isolate were 100% identical to sequences of the Xanthomonas perforans type strain. X. perforans local isolates showed similar genomic patterns with REP-PCR and fAFLP, and were clearly distinguished from other Xanthomonas spp. type strains. In stem-inoculation assays, bacteria isolated from symptomatic tomato plants identified as P. fluorescens, P. putida, P. marginalis, P. citronellolis, P. straminea, and Pantoea agglomerans induced discolouration of vascular tissues, while Pectobacterium carotovorum subsp. atrosepticum isolates induced soft rot. Conversely, the isolates here identified as Xanthomonas perforans were able to induce pith necrosis, vascular discolouration, longitudinal splits and external lesions on stems. This report of X. perforans causing pith necrosis on tomato represents a potentially serious problem that may limit the productivity of tomato crops.  相似文献   

18.
Fusarium species were consistently isolated from yellow, swollen spots with reddishbrown centers and small black spots on leaves of Cymbidium plants in the greenhouse. Fusarium subglutinans caused the yellow spots and Fusarium proliferatum caused either the yellow or the black spots. We propose the name “yellow spot” for the new disease. To denote differences in their pathogenicity to orchid plants, we designate the population causing yellow spot as race Y and that causing black spot as race B of F. proliferatum. Received 29 October 1999/ Accepted in revised form 10 March 2000  相似文献   

19.
在双孢蘑菇上发现一种新的病原菌:点枝顶孢菌(Acremonium strictum W.)。该菌侵染双孢蘑菇的子实体,形成不规则的褐色斑块,大小为(2-15)mm×(3-20)mm,病斑凹陷于菌肉或穿过菌肉组织直至菌褶,深达2-13 mmo病斑干枯不腐烂,俗你黑疤病或褐疤病。通过人工接菌观察了病害症状、发病规律、培养特性、形态特征,以及温度、pH对菌丝体生长和孢子萌发的影响。经室内外药剂筛选试验,明确克霉灵、甲醛、硫酸铜和石灰水可有效杀灭该病菌。  相似文献   

20.
Litchi (Litchi chinensis) pepper spot disease results in black spotting symptoms on litchi fruits. This disease was first observed on litchi cultivar Guiwei, in Guangzhou, China, in 2009, and then found widespread in other litchi-growing regions of China. Colletotrichum isolates were consistently recovered from typical black spot lesions of diseased fruits with frequency ranging from 83% to 100%. Three representative Colletotrichum isolates from Maoming, Guangzhou and Shenzhen were selected for identification and pathogenicity testing in the field. Based on morphology and phylogenetic analysis using the ribosomal internal transcribed spacer region (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), actin (ACT), β-tubulin (TUB2) and glutamine synthetase (GS) gene sequences, the three isolates were identified as C. siamense. In the pathogenicity experiments, typical symptoms appeared on the inoculated litchi fruits, including black spots and green patches around these black spots. These symptoms were consistent with the symptoms originally observed in the field. Colletotrichum siamense was successfully reisolated from the typical black spot lesions of the inoculated litchi fruits. To the authors' knowledge, this is the first report on characterization of C. siamense as the causal agent of litchi pepper spot disease in mainland China by successful inoculation on fruits under field conditions.  相似文献   

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