scholarly journals Pseudomonas syringae Leaf Blight, a New Disease of Kalmia latifolia

Plant Disease ◽  
1998 ◽  
Vol 82 (10) ◽  
pp. 1171-1171
Author(s):  
M. L. Putnam
Keyword(s):  
Pseudomonas Syringae ◽  
Acid Methyl Ester ◽  
Leaf Blight ◽  
Bacterial Suspension ◽  
Agar Culture ◽  
Kalmia Latifolia ◽  
Plastic Bags ◽  
Biolog System ◽  
Young Leaves ◽  
Affected Tissue

In spring and fall of 1997, and in February 1998, Kalmia latifolia cv. Olympic Fire plants with severe leaf blight symptoms were submitted to the Oregon State University Plant Clinic from a commercial nursery. The primary symptom was a dark purple leaf blight, often associated with the leaf mid-rib. Disease progressed down the petioles and into twigs, causing blackening of affected tissues and leaf drop. Abundant bacterial streaming was observed oozing from the margins of affected tissue when examined at ×100. Isolations from affected tissues were made onto King's medium B (KB). A fluorescent bacterium was recovered and identified as Pseudomonas syringae by the Biolog system of identification. Identity was confirmed by fatty acid methyl ester analysis performed by Larry Barnes (Texas A&M University, College Station). Attempts to determine the pathovar were unsuccessful. A single colony isolate of the bacterium was raised on KB. Koch's postulates were completed by the following procedures. A bacterial suspension was made from a 24-h-old agar culture of this isolate with phosphate buffer with 0.2% gelatin (PBG). The concentration of the suspension was adjusted to 8 × 107 cells per ml by direct enumeration. Five milliliters of the suspension was atomized onto young leaves on six twigs of Kalmia latifolia. Controls consisted of young leaves on four twigs atomized with 5 ml of PBG. Twigs receiving the inoculum or the PBG were enclosed in plastic bags and maintained at room temperature near a north-facing window. Symptoms appeared 6 days later: dark purple spots on the margins of inoculated leaves and blight symptoms near the leaf mid-rib. Symptoms did not appear on PBG-sprayed leaves. Pseudomonas syringae was successfully reisolated from surface-disinfested inoculated leaves but not from leaves sprayed with PBG. This is the first report of Pseudomonas syringae causing a leaf blight of Kalmia.

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 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 Leaf Blight and Stem Canker of Pachysandra terminalis Caused by Pseudonectria pachysandricola in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 287-287
Author(s):  
K. S. Han ◽  
J. H. Park ◽  
S. E. Cho ◽  
H. D. Shin
Keyword(s):  
United States ◽  
Its Region ◽  
Stem Canker ◽  
The United States ◽  
Culture Collection ◽  
Leaf Blight ◽  
First Report ◽  
Cornell University ◽  
Plastic Bags ◽  
Young Leaves

Pachysandra terminalis Siebold & Zucc., known as Japanese pachysandra, is a creeping evergreen perennial belonging to the family Buxaceae. In April 2011, hundreds of plants showing symptoms of leaf blight and stem canker with nearly 100% incidence were found in a private garden in Suwon, Korea. Plants with the same symptoms were found in Seoul in May and Hongcheon in August. Affected leaves contained tan-to-yellow brown blotches. Stem and stolon cankers first appeared as water soaked and developed into necrotic lesions. Sporodochia were solitary, erumpent, circular, 50 to 150 μm in diameter, salmon-colored, pink-orange when wet, and with or without setae. Setae were hyaline, acicular, 60 to 100 μm long, and had a base that was 4 to 6 μm wide. Conidiophores were in a dense fascicle, not branched, hyaline, aseptate or uniseptate, and 8 to 20 × 2 to 3.5 μm. Conidia were long, ellipsoid to cylindric, fusiform, rounded at the apex, subtruncate at the base, straight to slightly bent, guttulate, hyaline, aseptate, 11 to 26 × 2.5 to 4.0 μm. A single-conidial isolate formed cream-colored colonies that turned into salmon-colored colonies on potato dextrose agar (PDA). Morphological and cultural characteristics of the fungus were consistent with previous reports of Pseudonectria pachysandricola B.O. Dodge (1,3,4). Voucher specimens were housed at Korea University (KUS). Two isolates, KACC46110 (ex KUS-F25663) and KACC46111 (ex KUS-F25683), were accessioned in the Korean Agricultural Culture Collection. Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced using ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequence of 487 bp was deposited in GenBank (Accession No. JN797821). This showed 100% similarity with a sequence of P. pachysandricola from the United States (HQ897807). Isolate KACC46110 was used in pathogenicity tests. Inoculum was prepared by harvesting conidia from 2-week-old cultures on PDA. Ten young leaves wounded with needles were sprayed with conidial suspensions (~1 × 106 conidia/ml). Ten young leaves that served as the control were treated with sterile distilled water. Plants were covered with plastic bags to maintain a relative humidity of 100% at 25 ± 2°C for 24 h. Typical symptoms of brown spots appeared on the inoculated leaves 4 days after inoculation and were identical to the ones observed in the field. P. pachysandricola was reisolated from 10 symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in the United States, Britain, Japan, and the Czech Republic (2,3), but not in Korea. To our knowledge, this is the first report of P. pachysandricola on Pachysandra terminalis in Korea. Since this plant is popular and widely planted in Korea, this disease could cause significant damage to nurseries and the landscape. References: (1) B. O. Dodge. Mycologia 36:532, 1944. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 24, 2011. (3) I. Safrankova. Plant Prot. Sci. 43:10, 2007. (4) W. A. Sinclair and H. H. Lyon. Disease of Trees and Shrubs. 2nd ed. Cornell University Press, Ithaca, NY, 2005.

scholarly journals Report of Bacterial Leaf Spot on Collards and Turnip Leaves in Ohio

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 186-186 ◽  
Author(s):  
M. L. Lewis Ivey ◽  
S. Wright ◽  
S. A. Miller
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Similarity Index ◽  
Acid Methyl Ester ◽  
Bacterial Suspension ◽  
Water Control ◽  
Bacterial Leaf Spot ◽  
Turnip Leaves ◽  
Negative Controls

In 2000, circular water-soaked lesions typical of bacterial leaf spot were observed on leaves of collards (Brassica oleracea L. var. viridis) throughout commercial fields in northwest Ohio. Light brown, rectangular, water-soaked lesions were observed on turnip leaves (Brassica rapa L.). Bacterial streaming from lesions on both crops was observed microscopically. Cream colored, fluorescent colonies were isolated from diseased tissues on Pseudomonas F medium, and eight representative colonies (four from collards and four from turnip) were selected and purified. Fatty acid methyl ester analysis was performed on all of the isolates. Two from collards and two from turnip were identified as Pseudomonas syringae pv. maculicola (mean similarity index = 0.82 [MIDI Inc., Newark, DE]). DNA extracts from pure cultures of the P. syringae pv. maculicola strains were used as template in a polymerase chain reaction (PCR) assay with primers derived from the region of the coronatine gene cluster controlling synthesis of the coronafacic acid moiety found in P. syringae pv. tomato and P. syringae pv. maculicola (CorR and CorF2) (D. Cuppels, personal communication). DNA from P. syringae pv. tomato strain DC3000 and P. syringae pv. maculicola strain 88–10 (2) served as positive controls, while water and DNA from Xanthomonas campestris pv. vesicatoria strain Xcv 767 were used as negative controls. The expected 0.65-kb PCR product was amplified from three of four strains (two from turnip and one from collards) and the positive control DNA, but not from the negative controls. Pathogenicity tests were performed twice on 6-week-old turnip (‘Forage Star’, ‘Turnip Topper’, ‘Turnip Alamo’, ‘Turnip 7’), collard (‘Champion’) and mustard (Brassica juncea L. ‘Southern Giant Curl’) seedlings using the three PCR-positive strains. Premisted seedlings were spray-inoculated separately with each of the three strains (2 × 108 CFU/ml, 5 ml per plant) and a water control. Greenhouse temperatures were maintained at 20 ± 1°C. For both tests, all strains caused characteristic lesions on all of the crucifer cultivars within 5 days after inoculation; the control plants did not develop symptoms. To satisfy Koch's postulates, one of the turnip strains was reisolated from ‘Turnip Topper’ plants, and the collard strain was reisolated from ‘Champion’ plants. The three original and two reisolated strains induced a hypersensitive response in Mirabilis jalapa L. and Nicotiana tabacum L. var. xanthia plants 24 h after inoculation with a bacterial suspension (1 × 108 CFU/ml). The original and reisolated strains were compared using rep-PCR with the primer BOXA1R (1). The DNA fingerprints of the reisolated strains were identical to those of the original strains. To our knowledge, this is the first report of bacterial leaf spot on commercially grown collards and turnip greens in Ohio. References: (1) B. Martin et al. Nucleic Acids Res. 20:3479, 1992. (2) R. A. Moore et al. Can. J. Microbiol. 35:910, 1989.

scholarly journals First Report of Acidovorax avenae subsp. avenae Causing Bacterial Leaf Stripe of Strelitzia nicolai

Plant Disease ◽  
2011 ◽  
Vol 95 (11) ◽  
pp. 1474-1474 ◽  
Author(s):  
T. E. Seijo ◽  
N. A. Peres
Keyword(s):  
Pathogenic Bacteria ◽  
Fatty Acid Analysis ◽  
South Florida ◽  
Metabolic Phenotype ◽  
Bacterial Suspension ◽  
Rrna Gene ◽  
First Report ◽  
Plastic Bags ◽  
Young Leaves ◽  
Symptomatic Tissue

White bird of paradise (Strelitzia nicolai Regel & K. Koch) is a commonly grown ornamental in central and south Florida. Each summer of 2004 to 2007, a reoccurring disease was observed at a commercial nursery in central Florida. Diseased plants had brown, necrotic stripes between the lateral leaf veins, which usually appeared along the midvein and spread toward the leaf edge. Lesions developed on the youngest leaves as they emerged from the central whorl. During 2004 and 2005, 20 symptomatic leaves were sampled. A white, nonfluorescent bacterium was consistently isolated from symptomatic tissue. It induced a hypersensitive response (HR) on tomato, grew at 41°C, and was identified as a Acidovorax sp. based on fatty acid analysis and as Acidovorax avenae subsp. avenae by Biolog metabolic phenotype analysis (similarity 0.76 to 0.86). A partial 16S rRNA gene sequence (1,455 bp) (Accession No. EF418616) was identical to four sequences in the NCBI (National Center for Biotechnology Information) database: one from A. avenae subsp. avenae and three from A. avenae of undetermined subspecies. To confirm pathogenicity, a bacterial suspension (O.D590 = 0.1) was applied to fill the central whorl (~0.5 to 1 ml) of potted S. nicolai. Plants were incubated for 7 to 10 days inside plastic bags at ambient temperature. Plants were inoculated individually with five strains of A. avenae subsp. avenae, four from S. nicolai, and one from corn (ATCC19860). Two to nine plants per strain were inoculated in each experiment. All strains were tested at least twice and noninoculated control plants were included. Symptoms were reproduced on the emerging leaf of 50 to 100% of inoculated plants with all five A. avenae subsp. avenae strains. No symptoms were observed on the controls. The bacteria recovered from symptomatic tissue were confirmed to be A. avenae subsp. avenae. Corn seedlings were inoculated as described above, except that entire seedlings were sprayed. Water-soaked lesions along the length of older leaf blades developed in 4 to 7 days. Only the corn strain was pathogenic (>80% of seedlings symptomatic), indicating host specificity. To our knowledge, this is the first report of A. avenae subsp. avenae infecting S. nicolai. In 1971, Wehlburg (2) described the same symptoms on orange bird of paradise (S. reginae) as being caused by a nonfluorescent Pseudomonas sp. This report likely describes the same disease since the published description is consistent with symptoms caused by A. avenae subsp. avenae. The pathogen reported by Wehlburg (2) had one polar flagellum, reduced nitrate, produced oxidase and a HR, and utilized arabinose, but not sucrose or arginine, characteristics consistent with those of A. avenae subsp. avenae (1). The only difference was A. avenae subsp. avenae has a delayed positive starch hydrolysis (1), whereas Welhburg's strain was negative. This disease occurs mainly on young leaves when plants receive daily overhead irrigation. Incidence can be as high as 40%, occasionally causing mortality, but even mild symptoms affect appearance and reduce marketability as an ornamental. References: (1) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001. (2) C. Wehlburg. Plant Dis. Rep. 55:447, 1971.

scholarly journals Biology and Control of Bacterial Leaf Blight of Cornus mas

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 721-724 ◽  
Author(s):  
M.T. Mmbaga ◽  
E.C. Nnodu
Keyword(s):  
Disease Management ◽  
Pseudomonas Syringae ◽  
Bordeaux Mixture ◽  
Management Strategies ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Cupric Sulfate ◽  
Mature Leaves ◽  
Cornus Mas ◽  
Young Leaves

Cornelian cherry (Cornus mas L.) has been free of disease and pest problems until recently when a bacterial leaf blight caused by Pseudomonas syringae was reported. Since its first observation in middle Tennessee in 1999, the disease has become endemic in the nursery where it was first discovered. The objective of this study was to assess the disease, evaluate factors that favor disease development, and develop disease management strategies. Cool temperatures of 20 to 24 °C (day) and 10 to 15 °C (night) were most favorable to the disease and young leaves were highly susceptible while mature leaves were resistant to infection. Leaf wounding increased the susceptibility of leaves and mature leaves developed infection at 28 °C, temperature at which nonwounded leaves were completely resistant to infection. Results from this study also showed that plant propagation from seemingly healthy branches of infected plants may have perpetuated the disease at the nursery. Six chemicals—Phyton-27 (copper sulfate), Camelot (copper salt of fatty acids), Agri-Mycin 17 (streptomycin), Kocide 101 (copper hydroxide), Basicop (elemental copper 53%), and, Bordeaux mixture (cupric sulfate + lime) were evaluated for disease control. Phyton-27, and Agri-Mycin—were most effective and reduced disease severity to 10% of foliage showing disease symptoms. Information from this study will be useful in designing effective disease management strategies.

scholarly journals First Report of Bacterial Leaf Blight on Broccoli and Cabbage Caused by Pseudomonas syringae pv. alisalensis in South Carolina

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 132-132 ◽  
Author(s):  
W. P. Wechter ◽  
A. P. Keinath ◽  
M. W. Farnham ◽  
J. P. Smith
Keyword(s):  
South Carolina ◽  
Pseudomonas Syringae ◽  
Dna Analysis ◽  
Uv Light ◽  
Negative Control ◽  
Leaf Blight ◽  
Bacterial Suspension ◽  
Limiting Factor ◽  
Future Production ◽  
Pectolytic Activity

In May of 2009, leaf spot and leaf blight symptoms were observed on broccoli (Brassica oleracea var. italica) and cabbage (B. oleracea var. capitata) on several farms in Lexington County, the major brassica-growing region of South Carolina. Affected areas ranged from scattered disease foci within fields to entire fields. Initial infection symptoms on leaves of both crops included circular and irregular-shaped necrotic lesions that were 3 to 10 mm in diameter, often with yellow halos and water soaking. As the disease progressed, the lesions tended to coalesce into a general blight of the entire leaf. Diseased leaves from both broccoli and cabbage were collected from each of four fields at different locations in the county. Leaves were surface disinfested, macerated in sterile distilled water, then aliquots of the suspension were spread on King's medium B (KB) agar. All samples produced large numbers of bacterial colonies that fluoresced blue under UV light after 24 h of growth. In total, 23 isolates (13 from broccoli and 10 from cabbage) were collected. These isolates were gram negative, levan production positive, oxidase negative, pectolytic activity negative, arginine dihydrolase negative, and produced a hypersensitive response on tobacco, thus placing them in the Pseudomonas syringae LOPAT group (2). Two broccoli and two cabbage isolates were selected at random and tested for pathogenicity to cabbage cv. Early Jersey Wakefield, broccoli cv. Decicco, turnip cv. Topper, broccoli raab cv. Spring, collard cv. Hi-Crop, and oat cv. Montezuma in greenhouse tests. Bacteria were grown on KB agar for 24 h and a bacterial suspension was prepared and adjusted to an optical density of 0.1 at 600 nm. Three-week-old plants were spray inoculated to runoff and held at 100% relative humidity for 12 h after inoculation, prior to return to the greenhouse bench (4). P. syringae pv. maculicola strain F18 (4) and the pathotype strain of P. syringae pv. alisalensis BS91 were included as controls, along with a water-inoculated negative control. Plants were evaluated at 14 days postinoculation. The four unknown bacterial isolates and BS91 were pathogenic on all brassica plants tested, as well as on oat. In contrast, the P. syringae pv. maculicola strain F18 was not pathogenic on broccoli raab or oat. Symptoms produced by all isolates and strains tested were similar to those observed in the field. No symptoms were observed on water-inoculated plants. Comparative repetitive sequence-based (rep)-PCR DNA analysis using the BOXA1R primer (3) resulted in a DNA banding pattern of each of the isolates from the South Carolina fields (23 isolates), as well as those reisolated from inoculated plants, that was identical to P. syringae pv. alisalensis BS91 and differed from the P. syringae pv. maculicola F18 strain. On the basis of the rep-PCR assays and the differential host range (1), the current disease outbreak on broccoli and cabbage in South Carolina is caused by the bacterium P. syringae pv. alisalensis. Broccoli is a relatively new, albeit rapidly expanding, production vegetable in South Carolina; this disease may represent a limiting factor to future production. References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (3) J. Versalovic et al. Methods Mol. Cell. Biol. 5:25, 1994. (4) Y. F. Zhao et al. Plant Dis. 84:1015, 2000.

BIOASSAY TO DETERMINE CHERRY ROOTSTOCK TOLERANCE TO `BACTERIAL CANKER' CAUSED BY PSEUDOMONAS SYRINGAE PV SYRINGAE

HortScience ◽  
1990 ◽  
Vol 25 (11) ◽  
pp. 1354F-1355
Author(s):  
Elzbieta Krzesinska ◽  
Anita Nina Miller
Keyword(s):  
Relative Humidity ◽  
Pseudomonas Syringae ◽  
Bacterial Suspension ◽  
Avirulent Strain ◽  
Bacterial Canker ◽  
Symptom Development ◽  
Virulent Strains ◽  
Callus Production ◽  
Root Stock ◽  
One Year

An excised twig assay was developed to evaluate cherry geno-types for their tolerance to Pseudomonas syringae pv. syringae. One-year-old wood was collected at monthly intervals from October until January of `Royal Ann', `Corum', and a number of cherry rootstock. The rootstock included; F/12–1 and Giessen (GI) and M × M selections. A 2-cm incision (“^”-shaped flap) was made on each twig. A 20-μl droplet of inoculum or water was placed onto each incision. The inoculum was prepared with one avirulent (K4) and three virulent strains (W4N54, AP2, B15) concentrations (105, 106, or 107 cfu). Inoculated twigs were placed in test tubes and incubated at 15C in high relative humidity for 3 weeks. After incubation, twigs were evaluated for gummosis production (0–3, 0 = no gummosis), incision browning (1–4, 1 = yellow pith), and callus production (0–1, 0 = no callus). The concentration of bacterial suspension had no effect on symptom development. No gummosis or browning was observed on twigs inoculated with water or the avirulent strain. Based on the gummosis and browning ratings, rootstock M × M 2, M × M 39, M × M 60, GI 148-1, GI 154-2, and GI 154-4 were found to be resistant to these three strains of P. syringae in this assay. Root-stock F 12-1, GI 169–15, GI 172–9, and GI 173-9 were found to be tolerant.

scholarly journals First Report of Pseudomonas syringae pv. aptata Causing Bacterial Leaf Spot on Sugar Beet in Serbia

Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 281-281 ◽  
Author(s):  
V. Stojšin ◽  
J. Balaž ◽  
D. Budakov ◽  
Slaviša Stanković ◽  
I. Nikolić ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Leaf Surface ◽  
Negative Control ◽  
Gyrb Gene ◽  
Bacterial Suspension ◽  
Bacterial Strains ◽  
Gene Sequences ◽  
Bacterial Leaf Spot

A severe bacterial leaf spot was observed during June and July 2013 on commercial cultivars of sugar beet (Beta vulgaris var. saccharifera) in the Vojvodina Province of Serbia. Serbia is a major sugar beet production area in southeastern Europe, with 62,895 ha and 3 million tons of sugar beet yield in 2013. A foliar leaf spot observed in 25 commercial sugar beet fields surveyed ranged from 0.1 to 40% severity. Symptoms were characterized as circular or irregular, 5- to 20-mm diameter, white to light brown necrotic spots, each with a dark margin. Diseased leaves were rinsed in sterilized, distilled water (SDW) and dried at room temperature, and leaf sections taken from the margin of necrotic tissue were macerated in SDW. Isolations from 48 symptomatic leaves onto nutrient agar with 5% (w/v) sucrose (NAS) produced bacterial colonies that were whitish, circular, dome-shaped, and Levan-positive. Representative isolates (n = 105) were Gram negative; aerobic; positive for catalase, fluorescence on King's medium B, and tobacco hypersensitivity; and negative for oxidase, potato rot, and arginine dehydrolase. These reactions corresponded to LOPAT group Ia, which includes Pseudomonas syringae pathovars (2). Repetitive extragenic palindromic sequence (rep)-PCR was used for genetic fingerprinting the isolates using the REP, ERIC, and BOX primers. Twenty-five different profiles were obtained among the strains. From each profile group, one representative strain was sequenced for the gyrB gene (1). Four heterogenic groups were observed, and representative gyrB gene sequences of each group were deposited in the NCBI GenBank (Accession Nos. KJ950024 to KJ950027). The sequences were compared with those of pathotype strain P. syringae pv. aptata CFBP 1617 deposited in the PAMDB database; one strain was 100% homologous, and the other three were 99% homologous. To fulfill identification of the Serbian sugar beet isolates, gltA and rpoD partial gene sequences were determined (1), and the sequences were deposited as Accession Nos. KM386838 to KM386841 for gltA and KM386830 to KM38683033 for rpoD. The sequences were 100% homologous with those of pathotype strain CFBP 1617. Pathogenicity of each of four representative bacterial strains was tested on 3-week-old plants of the sugar beet cultivars Marinela, Serenada, and Jasmina (KWS, Belgrade, Serbia) and Lara (NS Seme, Novi Sad, Serbia) by atomizing a bacterial suspension of ~106 CFU/ml of the appropriate isolate onto the abaxial leaf surface of three plants per cultivar until water-soaking of the leaf surface was observed. Three plants of each cultivar atomized similarly with P. syringae pv. aptata CFBP 2473 and SDW served as positive and negative control treatments, respectively. Inoculated plants were kept in a clear plastic box at 80 to 100% RH and 17 ± 1°C and examined for symptom development over 3 weeks. For all test isolates and the control strain, inoculated leaves first developed water-soaked lesions 7 days after inoculation (DAI). By 10 to 14 DAI, lesions were necrotic and infection had spread to the petioles. By 21 DAI, wilting was observed on more than 50% of inoculated plants. Negative control plants were symptomless. Bacteria re-isolated onto NAS from inoculated leaves had the same colony morphology, LOPAT results, and gyrB partial gene sequences as described for the test strains. No bacteria were re-isolated from negative control plants. Based on these tests, the pathogen causing leaf spot on sugar beet in Serbia was identified as P. syringae pv. aptata. References: (1) P. Ferrente and M. Scortichini. Plant Pathol. 59:954, 2010. (2) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals A New Bacterial Disease on Bluberry (Vaccinium Corymbosum) Caused by Pseudomonas Spp.

2013 ◽  
Vol 53 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Monika Kałużna ◽  
Joanna Puławska ◽  
Beata Meszka
Keyword(s):  
Hypersensitivity Reaction ◽  
Pseudomonas Syringae ◽  
Vaccinium Corymbosum ◽  
Leaf Spot Disease ◽  
Bacterial Disease ◽  
Pseudomonas Spp ◽  
Leaf Spots ◽  
Pectolytic Activity ◽  
Young Leaves ◽  
First Time

Abstract In 2011, leaf spot disease was observed on the blueberry (Vaccinium corymbosum) cv. Nelson growing on a commercial field located in Central Poland. The disease symptoms could be seen as russet brown, irregular spots. The diameter of the spots was 0.3-0.5 cm, and the spots often coalesced. From these leaf spots, a fluorescent bacterium was repeatedly isolated in almost pure culture. Polymerase chain reaction (PCR) using primers Ps-for and Ps-rev, specific for Pseudomonas spp. confirmed that they belong to this genus. Based on LOPAT tests [levan production from sucrose (L), presence of oxidase (O), pectolytic activity on potato (P), the presence of arginine dihydrolase (A), hypersensitivity reaction on tobacco (T)], 6 isolates were classified to the LOPAT group Ib - group of Pseudomonas syringae subsp. savastanoi and Pseudomonas delphini, and one isolate to group Ia - P. syringae. All isolates caused a hypersensitivity reaction on tobacco plants, and symptoms similar to those under natural conditions, when young leaves of blueberry cv. Nelson were inoculated. Sequence analysis of 16S rRNA and rpoB genes showed the highest similarity of 6 studied strains to the species P. avellanae. Further taxonomic study is necessary to enable definitive classification of these isolates. It is the first time that a bacterial disease caused by the Pseudomonas spp. was observed in Poland.

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