scholarly journals Reaction of Indicator Tobacco Cultivars to Races of Pseudomonas syringaepv. tabaciTox+

2001 ◽  
Vol 19 (7) ◽  
pp. 353-359
Author(s):  
DL Cole ◽  
N Mapuranga
Keyword(s):  
Mixed Culture ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Angular Leaf Spot ◽  
Bacterial Suspension ◽  
Lesion Diameter ◽  
Colony Forming Units ◽  
Race 2 ◽  
Viable Culture

AbstractThree races of Pseudomonas syringaepv. tabaciTox+ (wildfire) (races 0, 1 and 2) and two races of Tox- (angular leaf spot) (races 1 and 2) have been confirmed on tobacco in Zimbabwe (Zim). Very few cultivars with no resistance to Ps. syringaepv. tabaci are grown commercially and race 0 has not been isolated since 1996. Because we no longer have a viable culture of race 0, we obtained an isolate of race 0 from Kentucky (0 KY), USA in January 2000. We included this isolate in race tests on standard indicator cultivars K E1 (susceptible to all races), KM 10 (resistance to race 0 derived from Nicotianalongiflora), WZ (resistance to races 0 and 1 derived from N. rustica) and a hybrid, K 35 (resistance to races 0 and 0 and 1 derived from N. longiflora and N. rustica respectively). Two leaves on 10-week-old seedlings were inoculated with a bacterial suspension (106 colony forming units [cfu] per mL) by spraying selected areas until just watersoaked and incubating the plants at 28 C and 70% RH for 10 d. The reaction to race 0, measured as lesion diameter, was different from that previously obtained with race 0 (Zim). Races 0 and 1 (Zim) are avirulent on WZ but race 0 (KY) was virulent. Further isolates of race 0 were received from Maryland (MD) and Tennessee (TN). The TN isolates overcame resistance derived from N. longiflora and N. rustica, except where both sets of genes were present in the same cultivar. Reactions have been variable with the race 0 (MD) isolate suggesting it is a mixed culture. We conclude that there are at least four races of Ps. syringaepv. tabaciTox+ worldwide and race 0 (KY) should be designated race 3. On all cultivars, race 2 consistently caused the largest lesions.

scholarly journals A New Race of Pseudomonas syringae pv. tabaci on Tobacco in Zimbabwe

Plant Disease ◽  
1998 ◽  
Vol 82 (12) ◽  
pp. 1404-1404 ◽  
Author(s):  
N. Mapuranga
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Treatment Resistance ◽  
Angular Leaf Spot ◽  
Ringer’S Solution ◽  
Fluorescent Pigment ◽  
Race 1 ◽  
Series Of Experiments ◽  
New Race ◽  
Race 2

Two forms of Pseudomonas syringae pv. tabaci cause wildfire (Tox+) and angular leaf spot (Tox-) diseases of tobacco in Zimbabwe. Two races of the pathogen (races 0 and 1) occur in Zimbabwe (4). Two groups of cultivars are available: one with resistance to race 0 only, tbe second with resistance to races 0 and 1 (4). P. syringae pv. tabaci was first observed on cultivars with resistance to races 0 and 1 in 1993, and infection on these cultivars is now widespread. The bacteria isolated from the infected plants were gram-negative rods and produced fluorescent pigment on King's medium B. Levan-oxidase-potato rot-arginine dihydrolase-tobacco hypersensitivity (LOPAT) tests indicated that the pathogen was a Group 1a pseudomonad (2). Pathogenicity and race designation for 58 isolates of the pathogen were determined on 8-week-old, greenhouse-raised tobacco plants. Inoculated plants were kept in controlled environment units (13/11 h photoperiod, 30 ± 2°C, relative humidity >75%) for 10 days. Pathogenicity was determined on cv. Kutsaga E1, which has no known resistance to any races of P. syringae pv. tabaci (4), and isolates from typical wildfire and angular leaf spot lesions were used for race designation by inoculating six plants of each indicator tobacco genotype. Genotypes included Nicotiana tabacum cv. Kutsaga E1 (susceptible to races 0, 1, and 2), which was used as the indicator genotype for race 0, N. longiflora (race 0 resistance) (1), N. tabacum cv. Kutsaga Mammoth 10 (resistance to race 0 derived from N. longiflora), N. rustica var. brasilea (resistance to races 0 and 1) (3,4), a breeding line, WZ 3-2-1-1, and cv. Kutsaga 35 (both resistant to races 0 and 1 with resistance derived from N. rustica var. brasilea). Six spots, three on either side of the midrib, were inoculated with an artist's airbrush (Aero-pro 251) operated at 250 kPa. The inoculum, (approximately 1 × 106 CFU/ml) suspended in a quarter-strength Ringer's solution was applied to one side of the midrib and Ringer's solution only to the other side, which served as control. Thirty-eight Tox+ isolates and 20 Tox- isolates were tested in a series of experiments in randomized complete blocks with four replications per treatment. Resistance to wildfire was characterized by localized chlorosis or whitish-tan hypersensitive lesions and susceptibility by necrotic lesions (>2 mm) surrounded by large chlorotic halos. Resistance to angular leaf spot was characterized by hypersensitive lesions or absence of symptoms and susceptibility by presence of symptoms (4). Sixty-six percent of the Tox+ isolates and 70% of the Tox- isolates successfully infected cultivars with known resistance to races 0 and 1, and were therefore designated race 2 (1). All other isolates were race 1. This is the first report of P. syringae pv. tabaci Tox+ and Tox- race 2 in Zimbabwe. References: (1) K. K. Knoche et al. Phytopathology 77:1364, 1987. (2). R. A. Lelliott and D. E. Stead. Methods in Plant Pathology. Vol. 2. 1987. (3). J. R. Stavely and H. A. Skoog. Proc. Am. Phytopathol. Soc. 3:231 (Abstr.), 1976. (4). J. J. Woodend and E. Mudzengerere. Euphytica 64:149, 1992.

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 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 Bacterial Leaf Spot of Coriander Caused by Pseudomonas syringae pv. coriandricola in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Lei Li ◽  
Yishuo Huang ◽  
Yanxia Shi ◽  
A LI CHAI ◽  
Xuewen Xie ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Citrate Synthase ◽  
Morphological Characteristics ◽  
Likelihood Method ◽  
Bacterial Suspension ◽  
Leaf Spot Disease ◽  
Distilled Water ◽  
Bacterial Leaf Spot ◽  
First Report

Coriander (Coriandrum sativum L.) or Chinese parsley is a culinary herb with multiple medicinal effects that are widely used in cooking and traditional medicine. From September to November 2019, symptoms were observed in 2-month-old coriander plants from coriander fields in Lanzhou and Wenzhou, China. The disease developed rapidly under cold and wet climatic conditions, and the infection rate was almost 80% in open coriander fields. Typical symptoms on leaves included small, water-soaked blotches and irregular brown spots surrounding haloes; as the disease progressed, the spots coalesced into necrotic areas. Symptomatic leaf tissue was surface sterilized, macerated in sterile distilled water, and cultured on nutrient agar plates at 28 °C for 48 h (Koike and Bull, 2006). After incubation, six bacterial colonies, which were individually isolated from collected samples from two different areas, were selected for further study. Colonies on NA plate were small, round, raised, white to cream-colored, and had smooth margins. All bacterial isolates were gram-negative, rod-shaped and nonfluorescent on King's B medium. The bacteria were positive for levan production, Tween 80 hydrolysis, and tobacco hypersensitivity but negative for oxidase, potato slice rot test, arginine dihydrolase, ice nucleation activity, indole production and H2S production. The suspension of representative isolate for inoculating of plants was obtained from single colony on King's B medium for 2-3 days at 28 °C. DNA was extracted from bacterial suspensions of YS2003200102 cultured in 20 ml of King’s B medium broth at 28 °C for 1 day. Extraction was performed with a TIANamp Bacterial DNA Kit (TIANGEN, China) according to the manufacturer’s recommendations. The pathogen was confirmed by amplification and sequencing of the glyceraldehyde-3-phosphate dehydrogenase A (gapA) gene, the citrate synthase (gltA) gene, the DNA gyrase B (gyrB) gene and the RNA polymerase sigma factor 70 (rpoD) gene using gapA-For/gapA-Rev, gltA-For/gltA-Rev, gyrB-For/gryB-Rev, rpoD-For/rpoD-Rev primers, respectively (Popović et al., 2019). The sequences of the PCR products were deposited in GenBank with accession numbers MZ681931 (gapA), MZ681932 (gltA), MZ681933 (gyrB), and MZ681934 (rpoD). Phylogenetic analysis of multiple genes (Xu and Miller, 2013) was conducted with the maximum likelihood method using MEGA7. The sequences of our isolates and ten published sequences of P. syringae pv. coriandricola were clustered into one clade with a 100% confidence level. To confirm the pathogenicity of isolate YS2003200102, 2-month-old healthy coriander plants were inoculated by spraying the leaves with a bacterial suspension (108 CFU ml−1) at 28 °C incubation temperature and 70% relative humidity condition, and sterile distilled water was applied as a negative control treatment (Cazorla et al. 2005). Three replicates were conducted for every isolate, and each replicate included 6 coriander plants. After twelve days, only the inoculated leaves with bacterial suspension showed bacterial leaf spot resembling those observed on naturally infected coriander leaves. Cultures re-isolated from symptomatic leaves showed the same morphological characteristics and molecular traits as those initially isolated from infected leaves in the field. This bacterium was previously reported causing leaf spot of coriander in India and Spain (Gupta et al. 2013; Cazorla et al. 2005). To our knowledge, this is the first report of P. syringae pv. coriandricola causing leaf spot disease on coriander in China. Studies are needed on strategies to manage P. syringae pv. coriandricola in crops, because its prevalence may cause yield loss on coriander in China.

scholarly journals First Report of Bacterial Leaf Spot Caused by Pseudomonas syringae pv. aptata on Swiss Chard, Beta vulgaris subsp. vulgaris, in Arizona

Plant Disease ◽  
2021 ◽  
Author(s):  
Marilen Nampijja ◽  
Mike Derie ◽  
Lindsey J. du Toit
Keyword(s):  
Beta Vulgaris ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Phosphate Buffer ◽  
Negative Control ◽  
Bacterial Suspension ◽  
Bacterial Leaf Spot ◽  
First Report ◽  
Leaf Spots ◽  
Swiss Chard

Arizona is an important region of the USA for winter production of baby leaf crops such as spinach (Spinacia oleracea), table beet (Beta vulgaris subsp. vulgaris Condivita Group), and Swiss chard (B. vulgaris subsp. vulgaris Cicla Group). In the winter of 2019, severe leaf spots were observed at 80% incidence and 40% severity per plant in a 1-ha baby leaf Swiss chard crop of an (unknown cultivar) in Arizona. The lesions were circular to irregular, necrotic, water-soaked, and 1 to 5 mm in diameter. Symptomatic leaf sections (1-cm2) were surface-sterilized with 0.6% NaOCl, rinsed, and macerated in sterilized, deionized water. An aliquot of each macerate was streaked onto King’s B (KB) agar medium. Cream-colored, non-fluorescent colonies typical of Pseudomonas were isolated consistently, and all were non-fluorescent. A dozen isolates selected randomly were all negative for potato soft rot, oxidase, and arginine dihydrolase, and positive for levan production and tobacco hypersensitivity, which is typical of fluorescent P. syringae isolates, but can also include non-fluorescent strains (Lelliot et al. 1966). Three isolates were tested for pathogenicity on the table beet cv. Red Ace and Swiss chard cv. Silverado. Strain Pap009 of P. syringae pv. aptata (Psa), demonstrated previously to be pathogenic on Swiss chard and table beet, served as a positive control strain (Derie et al. 2016; Safni et al. 2016). Each isolate was grown inoculated into medium 523 broth and incubated on a shaker at 175 rpm overnight at 25°C. Each bacterial suspension was adjusted to an optical density (OD) of 0.3 at 600 nm (108 CFU/ml), and diluted in 0.0125M phosphate buffer to 107 CFU/ml. Thirty-day-old seedlings grown in Redi-Earth Plug and Seedling Mix in a greenhouse at 22 to 26°C were inoculated by rubbing the abaxial and adaxial leaf surfaces of each plant with a cotton swab dipped in inoculum to which Carborundum had been added (0.06 g/10 ml). The negative control plants were treated similarly with phosphate buffer with Carborundum. The experiment was set up as a randomized complete block design with 4 replications per treatment and 6 seedlings per experimental unit. In both trials, leaf spots resembling those on the original plants developed on all table beet and Swiss chard plants inoculated with the Arizona isolates and Pap009, but not on negative control plants. Disease severity was greater on Swiss chard (average 39% leaf area with spots) than on table beet (14%). Re-isolates obtained from inoculated seedlings using the same method as the original isolations resembled Psa. Multilocus sequence analysis (MLSA) was carried out for the original three Arizona isolates and the re-isolates using DNA amplified from the housekeeping genes gyrB, rpoD, gapA, and gltA (Hwang et al. 2005; Sarkar and Guttman 2004). Sequence identities of these genes of the Arizona isolates (GenBank accession numbers MW291615 to MW291618 for strain Pap089; MW291619 to MW291622 for Pap095; and MW291623 to MW291626 for Pap096 for gltA, gyrB, rpoD, and gapA, respectively) and the re-isolates ranged from 98 to 100% with those of Psa pathotype strain CFBP 1617 in the PAMDB database (Almeida et al. 2010; Altschul et al. 1997). Based on Koch’s postulates, colony characteristics, and MLSA, Psa was the causal agent of leaf spots in the Arizona Swiss chard crop. To our knowledge, this is the first report of bacterial leaf spot on chard in Arizona. The pathogen could have been introduced on infected seed as Psa is readily seedborne and seed transmitted.

scholarly journals Amendment of Muskmelon and Watermelon Transplant Media with Plant Growth-Promoting Rhizobacteria: Effects on Seedling Quality, Disease, and Nematode Resistance

2003 ◽  
Vol 13 (3) ◽  
pp. 476-482 ◽  
Author(s):  
Nancy Kokalis-Burelle ◽  
C.S. Vavrina ◽  
M.S. Reddy ◽  
J.W. Kloepper
Keyword(s):  
Plant Growth ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Citrullus Lanatus ◽  
Plant Growth Promoting Rhizobacteria ◽  
Angular Leaf Spot ◽  
Root Weight ◽  
Didymella Bryoniae ◽  
Plant Growth Promoting ◽  
Growth Promoting

Greenhouse and field trials were performed on muskmelon (Cucumis melo) and watermelon (Citrullus lanatus) to evaluate the effects of six formulations of plant growth-promoting rhizobacteria (PGPR) that have previously been shown to increase seedling growth and induce disease resistance on other transplanted vegetables. Formulations of Gram-positive bacterial strains were added to a soilless, peat-based transplant medium before seeding. Several PGPR treatments significantly increased shoot weight, shoot length, and stem diameter of muskmelon and watermelon seedlings and transplants. Root weight of muskmelon seedlings was also increased by PGPR treatment. On watermelon, four PGPR treatments reduced angular leaf spot lesions caused by Pseudomonas syringae pv. lachrymans, and gummy stem blight, caused by Didymella bryoniae, compared to the nontreated and formulation carrier controls. One PGPR treatment reduced angular leaf spot lesions on muskmelon compared to the nontreated and carrier controls. On muskmelon in the field, one PGPR treatment reduced root-knot nematode (Meloidogyne incognita) disease severity compared to all control treatments.

Genetic mapping of angular leaf spot resistance to Pseudomonas syringae pv. lachrymans in a Cucumis hystrix introgression line of cucumber

Euphytica ◽  
2019 ◽  
Vol 215 (10) ◽  
Author(s):  
Kaijing Zhang ◽  
Yifan Wei ◽  
Martin Kagiki Njogu ◽  
Xing Wang ◽  
Qunfeng Lou ◽  
...  
Keyword(s):  
Genetic Mapping ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Introgression Line ◽  
Angular Leaf Spot ◽  
Cucumis Hystrix

scholarly journals Angular Leaf Spot of Cucumber Caused by Pseudomonas syringae pv. lachrymans in Kurdistan

Plant Disease ◽  
2007 ◽  
Vol 91 (6) ◽  
pp. 769-769 ◽  
Author(s):  
B. Harighi
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Biochemical Characterization ◽  
Protein Pattern ◽  
Disease Incidence ◽  
Angular Leaf Spot ◽  
Cell Protein ◽  
Fluorescent Pseudomonad ◽  
Cucumis Sativus L ◽  
Production Of Hydrogen

During the spring of 2004 and 2005, angular leaf spot was observed on cucumber (Cucumis sativus L.) in some areas of Kurdistan Province in Iran for the first time. Disease incidence in affected fields was approximately 100%. Symptoms were initially small, round or irregular, water-soaked spots on leaves ranging from 3 to 5 mm in diameter. These spots were limited by the leaf veins that gave them an angular appearance. Under humid conditions, tiny, white exudates formed on the undersides of the leaves and severely infected leaves turned yellow. A fluorescent pseudomonad was consistently isolated from lesions on King's medium B and characterized. Twelve strains were selected from Marivan, Dehgolan and Kamyaran in western Iran. When compared with previously identified strains, (1,2) on the basis of phenotypic, biochemical, and physiological properties, isolates were identified as Pseudomonas syringae pv. lachrymans. This was confirmed with data from whole-cell protein pattern analysis, which indicated that the strains were highly similar to reference strain 4963T (International Collection of Microorganism from Plants [ICMP]). Isolates produced round, white colonies that were 1 to 2 mm in diameter. All strains were gram negative, aerobic, levan positive, oxidase negative, potato soft rot negative, arginine dihydrolase negative, and induced a hypersensitive response on tobacco leaves. The strains were positive for catalase, urease, and 4% NaCl tolerance and negative for nitrate reduction, methyl red production, acetoin and indole production, phosphatase, gas from glucose, reducing substances from sucrose, and ketolactose tests. All strains hydrolyzed Tween 80, esculin, casein, and gelatin, but failed to hydrolyze starch and lecithin. Results for growth at 41°C and production of hydrogen sulfide from cystein and peptone were negative. In Ayers' medium, all strains produced acid from d-galactose, citrate, sucrose, raffinose, fructose, d-xylose, glucose, inositol, mannitol, sorbitol, glycerin, mannose, ribose but not from trehalose, maltose, salicin, l-rhamnose, adonitol, cellobiose, ethanol, l-sorbose, inulin, dulcitol, starch, lactose or melibiose. All strains used l-asparagine, l-lysine, aspartate and l-arginine but did not use l-tartrate, propionate, ornithine, l-tyrosine, borate, benzoate, l-tryptophan, or acetate as carbon sources. Pathogenicity of four strains was confirmed by injecting bacterial suspensions (108 CFU/ml) into the undersides of 3- to 4-week-old cucumber leaves using a sterile syringe. Sterile water was injected into cucumber leaves as a negative control. Inoculated plants were maintained in the greenhouse at 25 to 28°C with 90 to 98% relative humidity until symptoms were assessed 4 to 7 days after inoculation. Angular leaf lesions developed on inoculated cucumber. Bacterial strains were reisolated from infected tissues and confirmed as P. syringae pv. lachrymans by biochemical characterization as previously described. This disease has been observed in other areas of Iran, but to our knowledge, this is the first report that characterizes the phenotypic and biochemical properties of the bacterium and disease in Kurdistan Province. References: (1) D. J. Brenner et al. Bergy's Manual of Systematic Bacteriology. 2nd ed. Springer, New York, NY, 2005. (2) D. C. Sands et al. J. Bacteriol. 101:9, 1970.

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