scholarly journals Bacterial Blight, a New Disease of Broccoli Caused by Pseudomonas syringae in California

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 370-370 ◽  
Author(s):  
S. T. Koike ◽  
N. A. Cintas ◽  
C. T. Bull
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Nutrient Broth ◽  
New Disease ◽  
Initial Symptoms ◽  
Salinas Valley ◽  
Bacterial Blight Pathogen ◽  
Dark Green

In 1998 and 1999, a new disease was detected in commercial broccoli (Brassica oleracea var. botrytis) grown in the Salinas Valley, Monterey County, CA. Initial symptoms consisted of large, water-soaked, dark green, angular leaf sections that were bordered by major leaf veins. Diseased areas were as large as 10 × 3 cm. As the disease developed, affected areas turned tan and papery, and leaf margins sometimes became tattered. The numerous small (<1 cm diameter), round to angular spots that also were present retained their size and did not develop into larger lesions. A blue-green fluorescing pseudomonad was consistently isolated from both types of lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum L. ‘Turk’). Fatty acid methyl ester analysis (MIS-TSBA version 4.10, MIDI, Inc., Newark, DE) indicated that the strains were highly similar (similarity ≥0.843) to Pseudomonas syringae. Biolog GN (version 3.50, Biolog, Inc., Hayward, CA) profiles also identified the strains as P. syringae. Therefore, the bacterium associated with the disease was identified as P. syringae. Pathogenicity of 13 strains was demonstrated by greenhouse tests. The strains were grown as nutrient broth shake cultures for 48 h at 24°C, diluted to 106 CFU/ml, and misted onto broccoli (cvs. Patriot and Titleist) and broccoli raab (B. rapa subsp. rapa cv. Spring). Control plants were misted with sterile nutrient broth. After 4 to 5 days in a greenhouse (24 to 26°C), large angular leaf lesions developed on all inoculated broccoli and broccoli raab plants. Strains were reisolated from symptomatic tissue and identified as P. syringae. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. Unlike most P. syringae strains, those isolated from broccoli were sensitive to a bacteriophage recovered from a P. syringae pathovar that infects broccoli raab. These results suggest that the broccoli pathogen may be related to the bacterial blight pathogen of broccoli raab (1). This is the first report of this pathogen causing a disease on commercially grown broccoli. Reference: (1) S. T. Koike et al. Plant Dis. 82:727, 1998.

scholarly journals A New Bacterial Leaf Spot Disease of Broccolini, Caused by Pseudomonas syringae pathovar maculicola, in California

Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1207-1207 ◽  
Author(s):  
N. A. Cintas ◽  
C. T. Bull ◽  
S. T. Koike ◽  
H. Bouzar
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Similarity Index ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Nutrient Broth ◽  
Leaf Spot Disease ◽  
Fluorescent Pseudomonad ◽  
Bacterial Leaf Spot ◽  
Initial Symptoms

In 1998, a new disease was detected on 3-week-old commercial broccolini (Brassica oleracea L. var. botrytis × B. alboglabra) transplants in a Salinas Valley, Monterey County, CA greenhouse. Initial symptoms were small (2 to 4 mm diameter) circular to angular, water-soaked spots. As the disease progressed, spots remained relatively small, but turned tan to brown. When diseased tissues were macerated and streaked on King's medium B, a blue-green fluorescent pseudomonad was consistently isolated. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices, but induced a hypersensitive reaction on tobacco (Nicotiana tabacum L. ‘Turk’). Fatty acid methyl ester analysis (MIS-TSBA, version 4.10, MIDI Inc., Newark, DE) indicated that strains had a high similarity index (0.82 or higher) to Pseudomonas syringae, and GN (version 3.50, Biolog, Inc., Hayward, CA) profiles also identified strains as P. syringae. The bacterium associated with the disease, therefore, was identified as P. syringae van Hall. Pathogenicity was demonstrated by growing inoculum in nutrient broth shake cultures for 48 h, misting the broth cultures (1×106 CFU/ml) onto broccolini (cv. Aspabrock), and subjecting the plants to 48 h of high humidity. Control plants were misted with sterile nutrient broth. After 4 to 5 days in a greenhouse, leaf spot symptoms developed on all inoculated broccolini plants, and reisolated strains were characterized and found to be P. syringae. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. Repetitive sequence-based polymerase chain reaction using the BOXA1R primer resulted in identical banding patterns for the broccolini pathogen and for known isolates of P. syringae pv. maculicola from crucifers. In host range testing, P. syringae pv. maculicolawas pathogenic to broccolini plants. The broccolini isolates and P. syringae pv. maculicola isolates had the same pathogenicity results when crucifers and tomatoes were tested as hosts; broccoli and cauliflower (B. oleracea var. botrytis) were infected, and tomato results were variable. These tests suggest that the broccolini pathogen is the bacterial leaf spot pathogen, Pseudomonas syringae pv. maculicola, that occurs on broccoli and cauliflower transplants (1). To our knowledge, this is the first report of this pathogen causing a disease on commercially grown broccolini. Reference: (1) S. T. Koike et al. Plant Dis. 82:727, 1998.

scholarly journals Bacterial Blight on Arugula, a New Disease Caused by Pseudomonas syringae pv. Alisalensis in California

Plant Disease ◽  
2004 ◽  
Vol 88 (12) ◽  
pp. 1384-1384 ◽  
Author(s):  
C. T. Bull ◽  
P. Goldman ◽  
S. T. Koike
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Nutrient Broth ◽  
Leaf Spot Disease ◽  
Diagnostic Feature ◽  
Fluorescent Pseudomonad ◽  
Fresh Market ◽  
Banding Patterns

Beginning in 1995, a leaf spot disease has occasionally developed on the leafy crucifer arugula (Eruca vesicaria subsp. sativa) that is grown in coastal California as a fresh market commodity used mostly in bagged salad mixes. Initially, symptoms consist of small (<2 mm in diameter), angular, water-soaked spots that are visible from both sides of the leaf. The spots later enlarge, remain angular in shape, and turn brown to tan. A purple margin sometimes occurs around the spots. An important diagnostic feature is that this disease closely resembles downy mildew infections that have not produced sporangia (3). A blue-green fluorescent pseudomonad was consistently isolated from both types of lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction on tobacco (Nicotiana tabacum L. cv. Turk). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (4). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10; MIDI, Inc., Newark, DE), which indicated that the strains were highly similar (similarity > = 0.758) to Pseudomonas syringae. Amplification of repetitive bacterial sequence-based polymerase chain reaction (rep-PCR) was used to determine the relationship between the P. syringae strains isolated from arugula and two common crucifer pathogens, P. syringae pv. maculicola and P. syringae pv. alisalensis (1). Using the BOXA1R primer, banding patterns for the arugula strains and the P. syringae pv. alisalensis pathotype were similar, differing by only one band. In contrast, the banding patterns of the arugula strains differed significantly from those of P. syringae pv. maculicola. Additionally, the arugula isolates were sensitive to a bacteriophage originally isolated for its ability to lyse P. syringae pv. alisalensis (1). Previously, the pathogen from arugula was reported to be P. syringae pv. maculicola (2). It is the intent of this disease note to clarify this identification. We completed Koch's postulates by confirming pathogenicity on arugula (cv. Rocket Salad). The strains were grown as nutrient broth shake cultures for 48 h at 24°C, adjusted to 108 CFU/ml, and misted onto 2- to 3-week old plants. Control plants were misted with sterile nutrient broth. After 4 to 5 days in a greenhouse (24 to 26°C), large, angular leaf lesions developed on all inoculated arugula plants. Strains were reisolated from symptomatic tissue and identified as P. syringae pv. alisalensis. Control plants remained symptomless. Similar methods confirmed that the host range of the arugula isolates were identical to that of P. syringae pv. alisalensis. The arugula and P. syringae pv. alisalensis isolates caused disease on broccoli (Brassica oleracea var. botrytis cvs. Patriot and Titleist), broccoli raab (B. rapa subsp. rapa cv. Sorento), and oats (Avena sativa cv. Montezuma), while P. syringae pv. maculicola caused disease on broccoli only. Pathogenicity tests were conducted two times with identical results. This confirms that the bacterial blight that has been occurring on commercial plantings of arugula is caused by P. syringae pv. alisalensis. References: (1) N. A. Cintas et al.Plant Dis. 86:992, 2002. (2) S. T. Koike et al. Plant Dis. 80:464, 1996. (3) S. T. Koike. Plant Dis. 82:1063, 1998. (4) R. A. Lelliott, J. Appl. Bacteriol. 29:470, 1966.

scholarly journals Bacterial Blight of Broccoli Raab: A New Disease Caused by a Pathovar of Pseudomonas syringae

Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 727-731 ◽  
Author(s):  
Steven T. Koike ◽  
Diana M. Henderson ◽  
Hamid R. Azad ◽  
Donald A. Cooksey ◽  
E. L. Little
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Toxin Production ◽  
Grass Species ◽  
New Disease ◽  
Leaf Spots ◽  
Leaf Yellowing ◽  
Salinas Valley ◽  
Cruciferous Plants ◽  
Test Plants

Bacterial blight is a new disease of broccoli raab or rappini (Brassica rapa subsp. rapa) that has developed on commercially grown crops in the Salinas Valley (Monterey County) in California. Symptoms consist of small, angular, water-soaked flecks on lower foliage that are visible from both adaxial and abaxial sides of the leaves. These flecks expand and become surrounded by bright yellow borders. With time, multiple leaf spots coalesce and result in large, irregular necrotic areas, extensive leaf yellowing, and eventual leaf death. If symptoms develop on the uppermost leaves attached to the inflorescence, the shoot loses market quality and will not be harvested. Pseudomonas syringae was consistently isolated from symptomatic plants, and selected strains caused similar symptoms when inoculated onto broccoli raab test plants. Broccoli raab strains caused leaf spot symptoms on nine other Cruciferous plants, as well as on three grass species (California brome, oat, and common timothy). Conversely, broccoli raab was not infected by P. syringae pathovars coronafaciens, maculicola, and tomato. Broccoli raab strains were positive for coronatine toxin production. Fatty acid analyses indicated that the P. syringae from broccoli raab was most closely related to P. syringae pvs. coronafaciens and maculicola, but its distinct host range suggests that it may be considered a separate pathovar.

Bacterial Blight, a New Disease of Broccoli Caused by Pseudomonas syringae in California

2000 ◽  
Vol 1 (1) ◽  
pp. 35 ◽  
Author(s):  
S. T. Koike ◽  
N. A. Cintas ◽  
C. T. Bull
Keyword(s):  
Brassica Oleracea ◽  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
New Disease ◽  
Salinas Valley ◽  
Monterey County

In 1998 and 1999, a new disease was detected in commercial broccoli (Brassica oleracea var. botrytis) grown in the Salinas Valley, Monterey County, CA. Posted 1 June 2000.

scholarly journals First Report of Bacterial Blight of Romanesco Cauliflower (Brassica oleracea var. botrytis) Caused by Pseudomonas syringae pv. alisalensis in California

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1551-1551 ◽  
Author(s):  
S. T. Koike ◽  
K. Kammeijer ◽  
C. T. Bull ◽  
D. O'Brien
Keyword(s):  
Brassica Oleracea ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Bacterial Suspension ◽  
First Report ◽  
Plastic Bags ◽  
Initial Symptoms ◽  
Infested Field

In 2005, a new disease was detected on commercial, organically grown romanesco (green) cauliflower (Brassica oleracea var. botrytis) grown in San Benito County, California. Initial symptoms consisted of small (1 to 2 mm in diameter), angular, water-soaked flecks. These flecks developed into tan-to-gray, angular lesions measuring as much as 5 mm in diameter. Lesions were usually surrounded by chlorotic borders. Coalescing lesions caused the leaf to turn papery in texture and have a blighted appearance. A blue-green fluorescing pseudomonad was consistently isolated from lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10, MIDI, Inc., Newark, DE), which showed that the strains were highly similar (similarity = 0.921 or greater) to Pseudomonas syringae. Amplification of repetitive bacterial sequences (rep-PCR) using the BOXA1R primer and the polymerase chain reaction resulted in identical banding patterns for the romanesco strains and the P. syringae pv. alisalensis pathotype strain. Pathogenicity was demonstrated by growing inoculum of six strains in nutrient broth shake cultures for 48 h (24°C), adjusting the bacterial suspension to 106 CFU/ml, and spraying the resulting suspension onto green cauliflower (cv. Romanesco Precoce). Plants were enclosed in plastic bags for 24 h and then incubated in a greenhouse (24 to 26°C). Control plants were misted with sterile water and treated the same way. After 5 days, foliar symptoms identical to symptoms seen in the field developed on all inoculated plants, and reisolated strains were characterized and found to be identical to P. syringae pv. alisalensis by the tests described above. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. To our knowledge, this is the first report of commercially grown romanesco green cauliflower as a host of P. syringae pv. alisalensis. The infested field had approximately 30% of the plants affected, with perhaps 10% sustaining some crop loss. This bacterial pathogen has previously been reported on commercial plantings of arugula (Eruca sativa), broccoli (Brassica oleracea var. botrytis), and broccoli raab (Brassica rapa var. rapa) and under experimental (greenhouse) conditions causes disease on additional hosts, including members of the Poaceae (1). References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Bacterial Blight of Mulberries Caused by Pseudomonas syringae pv. mori in the Eastern Anatolia Region of Turkey

Plant Disease ◽  
1999 ◽  
Vol 83 (12) ◽  
pp. 1176-1176 ◽  
Author(s):  
F. Sahin ◽  
R. Kotan ◽  
M. F. Dönmez
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Disease Incidence ◽  
Similarity Index ◽  
Acid Methyl Ester ◽  
Central Anatolia ◽  
Eastern Anatolia ◽  
First Report ◽  
Fame Analysis ◽  
Initial Symptoms

During spring 1999, a severe bacterial blight disease was observed on white mulberry (Morus alba L.) trees grown in the Erzincan, Erzurum, and Artvin provinces in the eastern Anatolia region of Turkey. Initial symptoms appeared as small, water-soaked spots on leaves and shoots. The spots eventually expanded and resulted in dark brown to black, elongated, stripe-like lesions on shoots. Diseased leaves wilted at the twig tips and later died. Disease incidence was close to 100% in the regions surveyed. Fluorescent bacteria were isolated consistently from lesions on diseased leaves and shoots on King's medium B. Morphological and biochemical characteristics of 16 presumptive strains tested were rod-shaped, aerobic, gram negative, oxidase negative, and catalase and levan positive. None of the strains reduced nitrate or hydrolyzed gelatin. All strains were confirmed as Pseudomonas syringae by gas-chromatography fatty acid methyl ester (GC-FAME) analysis, with a similarity index ranging from 0.82 to 0.94. The pathogen was identified as P. syringae pv. mori based on pathogenicity tests performed by spray-inoculating healthy leaves (M. alba cv. Beyaz Dut) on 1-year-old host twigs with suspensions of 108 CFU/ml each strain (2). Inoculated plants and sterile water-sprayed controls were maintained in a greenhouse at 18 to 28°C. Plants were covered with polyethylene bags for 48 h after inoculation. Within 7 to 10 days, necrotic spots typical of those found in the nursery were observed on inoculated leaves. No symptoms were seen on control plants. The pathogen was reisolated from lesions on inoculated leaves. Recovered strains were identical to initial strains, based on morphological and biochemical tests and GC-FAME analysis. To our knowledge, the occurrence and incidence of this disease in different geographic regions of Turkey, except the central Anatolia and Aegean regions, have not been studied (1). This is the first report of bacterial blight of mulberries at high incidence in the eastern Anatolia region of Turkey. References: (1) K. Türkolu and Y. E. Öktem. Plant Prot. Bull 13:19, 1973. (2) J. M. Young et al. N. Z.J. Agric. Res. 21:159, 1978.

scholarly journals First Report of Bacterial Blight of Rutabaga (Brassica napus var. napobrassica) Caused by Pseudomonas syringae pv. alisalensis in California

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 112-112 ◽  
Author(s):  
S. T. Koike ◽  
K. Kammeijer ◽  
C. T. Bull ◽  
Doug O'Brien
Keyword(s):  
Brassica Napus ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Acid Methyl Ester ◽  
Hypersensitive Reaction ◽  
Bacterial Suspension ◽  
Experimental Conditions ◽  
First Report ◽  
Plastic Bags ◽  
Initial Symptoms

In 2005, commercial, organically grown rutabaga (Brassica napus var. napobrassica) in San Benito County, CA showed symptoms of a previously undescribed disease on approximately 30% of the plants. Initial symptoms consisted of small (1 to 2 mm in diameter), angular, water-soaked flecks that often were surrounded by chlorotic haloes. These flecks enlarged and coalesced into large, irregularly shaped, gray brown lesions that could be as long as 10 mm. Lesions were visible from both adaxial and abaxial leaf surfaces and generally retained the chlorotic borders. A blue-green fluorescing pseudomonad was consistently isolated from lesions on King's medium B. Eight isolates were characterized and were levan positive, oxidase negative, and arginine dihydrolase negative. Isolates did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10; MIDI, Inc., Newark, DE) that showed that the isolates were highly similar (similarity = 0.922 or greater) to Pseudomonas syringae. Amplification of repetitive bacterial sequences (rep-PCR) using the BOXA1R primer and the polymerase chain reaction resulted in identical banding patterns for the rutabaga isolates and the P. syringae pv. alisalensis pathotype strain. Pathogenicity was demonstrated by growing inocula of six isolates in nutrient broth shake cultures for 48 h (24°C), adjusting the bacterial suspension to 106 CFU/ml, and misting the resulting suspensions onto rutabaga (cv. American Purple Top). Plants were enclosed in plastic bags for 24 h and then incubated in a greenhouse (24 to 26°C). Control plants were misted with sterile water and treated the same way. After 5 to 7 days, foliar symptoms similar to symptoms seen in the field developed on all inoculated plants, and reisolated bacteria were characterized and found to be P. syringae pv. alisalensis. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. To our knowledge, this is the first report of commercially grown rutabaga as a host of P. syringae pv. alisalensis and the first report of a B. napus host of this pathogen. This bacterial pathogen has previously been reported on commercial plantings of arugula (Eruca sativa), broccoli (Brassica oleracea var. botrytis), and broccoli raab (Brassica rapa var. rapa) in California and under experimental conditions it causes disease on additional hosts, including members of the Poaceae (1). References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Bacterial Leaf Spot of Spinach Caused by a Pseudomonas syringae Pathovar in California

Plant Disease ◽  
2002 ◽  
Vol 86 (8) ◽  
pp. 921-921 ◽  
Author(s):  
S. T. Koike ◽  
H. R. Azad ◽  
D. C. Cooksey
Keyword(s):  
Brassica Oleracea ◽  
Beta Vulgaris ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
The United States ◽  
Nutrient Broth ◽  
Bacterial Leaf Spot ◽  
First Report ◽  
Leaf Spots ◽  
Initial Symptoms

In 2000 and 2001, a new disease was observed on commercial spinach (Spinacia oleracea) in the Salinas Valley, Monterey County, CA. Initial symptoms were water-soaked, irregularly shaped leaf spots (2 to 3 mm diameter). As the disease developed, spots enlarged to as much as 1 to 2 cm, were vein-delimited, and turned dark brown. Faint chlorotic halos sometimes surrounded the spots. Death of large areas of the leaf occurred if spots coalesced. Spots were visible from the adaxial and abaxial sides of leaves, and no fungal structures were observed. The disease occurred on newly expanded and mature foliage. No fungi were isolated from the spots. However, cream-colored bacterial colonies were consistently isolated on sucrose peptone agar, and these strains were nonfluorescent on King's medium B. Strains were positive for levan and negative for oxidase, arginine dihydrolase, and nitrate reductase. Strains did not grow at 36°C, did not rot potato slices, but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Turk). These results suggested the bacterium was similar to Pseudomonas syringae. Fatty acid methyl ester (FAME) analysis (MIS-TSBA 4.10, MIDI Inc., Newark, DE) indicated the strains were highly similar (80.1 to 89.3%) to P. syringae pv. maculicola. However, in contrast to P. syringae pv. maculicola, the spinach strains did not utilize the carbon sources erythritol, L+tartrate, L lactate, and DL-homoserine. Pathogenicity of 10 strains was tested by growing inoculum in nutrient broth shake cultures for 48 h, diluting to 106 CFU/ml, and spraying 4-week-old plants of spinach cv. Bossanova. Control plants were sprayed with sterile nutrient broth. After 5 to 8 days in a greenhouse (24 to 26°C), leaf spots identical to those observed in the field developed on cotyledons and true leaves of inoculated plants. Strains were reisolated from the spots and identified as P. syringae. Control plants remained symptomless. The 10 strains were also inoculated on beet (Beta vulgaris), Swiss chard (Beta vulgaris subsp. cicla), cilantro (Coriandrum sativum), and spinach. Spinach showed leaf spots after 8 days; however, none of the other plants developed symptoms. Two strains were inoculated onto spinach cvs. Califlay, Lion, Nordic IV, Polka, Resistoflay, Rushmore, RZ 11, Spinnaker, Springfield, Viroflay, and Whitney. Leaf spot developed on all cultivars, and the pathogen was reisolated. Because the FAME data indicated a similarity between the spinach pathogen and P. syringae pv. maculicola, we inoculated sets of spinach cv. Bolero, cabbage (Brassica oleracea subsp. capitata cv. Grenedere), and cauliflower (Brassica oleracea subsp. botrytis cv. White Rock) with three P. syringae pv. maculicola and three spinach strains. Cabbage and cauliflower developed leaf spots only when inoculated with P. syringae pv. maculicola; spinach had leaf spots only when inoculated with the spinach strains. All inoculation experiments were done twice, and the results of the two tests were the same. To our knowledge, this is the first report of bacterial leaf spot of spinach in California caused by a nonfluorescent P. syringae, and the first record of this disease in the United States. Biochemical characteristics and limited host range of the pathogen indicate the California strains are likely the same as the P. syringae pv. spinaciae pathogen that was reported in Italy (1) and Japan (2). References: (1) C. Bazzi et al. Phytopathol. Mediterr. 27:103, 1988. (2) K. Ozaki et al. Ann. Phytopathol. Soc. Jpn. 64:264, 1998.

scholarly journals First Report of Bacterial Blight Caused by Pseudomonas syringae pv. pisi on Pea in Turkey

Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 923-923 ◽  
Author(s):  
K. Benlioglu ◽  
Ü. Özyilmaz ◽  
D. Ertan
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
Disease Incidence ◽  
Peat Soil ◽  
Green Water ◽  
Western Anatolia ◽  
Limiting Factor ◽  
First Report ◽  
Future Production ◽  
Initial Symptoms

In April of 2009, leaf blight symptoms were observed on field peas (Pisum sativum L.) grown in Söke, Torbali, and Ödemis counties in the Aegean Region of Turkey. Field inspections revealed disease incidence as high as 45% and the disease was found in 13 commercial fields. Initial symptoms consisted of small, dark green, water-soaked lesions on leaves, stipules, and stems near ground level. Lesions often enlarged and coalesced and turned chocolate brown with a water-soaked margin. Stem infections usually coalesced and girdled the stem spreading upward to stipules and leaflets forming a fan-like lesion on the stipule. A fluorescent, gram-negative bacterium was consistently isolated from diseased tissues onto King's B medium. Twelve strains (five from cv. Early Sweet, three from cv. Geneva, two from cv. Bolero, and two from cv. Carina) from thirteen pea fields were obtained. All strains metabolized glucose oxidatively, and their reactions in LOPAT tests were +, —, —, —, +, and thus classified as belonging to Pseudomonas syringae LOPAT group Ia (1). The 12 strains utilized homoserine, inositol, sorbitol, sucrose, mannitol, and mannose but did not utilize erythritol, trehalose, and L-tartarate. All showed ice nucleation activity but variable results were obtained for gelatin liquefaction and esculin hydrolysis. Identification of P. syringae pv. pisi was confirmed by sequencing the 16S rDNA with primers Univ-1390R (3) and 27F (2). Sequences of the three local strains (Bz2, Bz4, and Bz8) were 100% identical to a type culture strain. The nucleotide sequence of strain Bz4 was submitted to GenBank (Accession No. GU332546). Pathogenicity tests were performed on greenhouse-grown 2-week-old pea plants cv. Geneva as three replicates in 12-cm pots containing a steamed sand/peat/soil mixture. Plants were stab inoculated by puncturing the main stem at its junction with the stipules at the second node from the apical end with a 26-gauge needle through a 5-μl drop of 108 CFU/ml bacterial suspensions. Control plants were inoculated with sterile water. After 10 days of incubation in a growth chamber at 24 ± 1°C with a 14-h photoperiod, stems inoculated with pea isolates resulted in water-soaked tissue spreading from the site of inoculation along the veins on stipules and leaflets that were identical to symptoms seen in the field. Control plants remained symptomless. Isolates recovered from the symptomatic stems showed the same morphological and biochemical features of the original isolates. All physiological and biochemical tests as well as the pathogenicity assay were performed at least twice and the type strain of P. syringae pv. pisi (NCPPB 2585) was used as reference. On the basis of the physiological, biochemical, genetic, and pathological characteristics, all strains were identified as P. syringae pv. pisi. To our knowledge, this is the first report of P. syringae pv. pisi causing bacterial blight on pea in Turkey. Turkey currently produces approximately 93.000 t of peas annually and three-quarters of that is produced in Western Anatolia. The new disease may represent a limiting factor for future production. References: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (2) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991. (3) D. Zeng et al. Appl. Environ. Microbiol. 62:4504, 1996.

scholarly journals Bacterial Blight of Shallot, Caused by Pseudomonas syringae pv. porri, a New Disease in Korea

2012 ◽  
Vol 28 (4) ◽  
pp. 454-454 ◽  
Author(s):  
Inn-Shik Myung ◽  
Young-Kee Lee ◽  
Hongsik Shim
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Blight ◽  
New Disease
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