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.

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 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 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 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 leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain

Plant Disease ◽  
2021 ◽  
Author(s):  
José Luis Palomo Gómez ◽  
Maria Shima ◽  
Adela Monterde ◽  
Inmaculada Navarro ◽  
Silvia Barbé ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Xanthomonas Campestris ◽  
Negative Control ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Pcr Analysis ◽  
Bacterial Suspension ◽  
Rrna Gene ◽  
Distilled Water ◽  
First Report

In September 2019, symptoms resembling those of bacterial leaf blight were observed on carrot plants (Daucus carota L. subsp. sativus Hoffm.) cv. Romance cultivated in commercial plots in Chañe (Segovia), Spain. Symptoms were observed in two plots surveyed representing three hectares, with an incidence greater than 90%, and also in some plots in other nearby municipalities sown with the same batch of seeds. The lesions observed at the ends of the leaves were initially yellow that develop dark brown to black with chlorotic halos on leaflets that turned necrotic. Yellow, Xanthomonas-like colonies were isolated onto YPGA medium (Ridé 1969) from leaf lesions. Two bacterial isolates were selected and confirmed by real-time PCR using a specific primer set for Xanthomonas hortorum pv. carotae (Temple et al. 2013). All isolates were gram-negative, aerobic rods positive for catalase, able of hydrolyzing casein and aesculin and growing at 2% NaCl, while were negative for oxidase and urease tests. Sequences of 16S rRNA gene showed 100% similarity with Xanthomonas campestris, X. arboricola, X. gardneri, X. cynarae strains (GenBank accession numbers: MW077507.1 and MW077508.1 for the isolates CRD19-206.3 and CRD19-206.4, respectively). However, the resulting phylogeny of multilocus sequence analysis (MLSA) of a concatenation of the housekeeping genes atpD, dnaK, and efp (Bui Thi Ngoc et al. 2010), by using neighbour-joining trees generated with 500 bootstrap replicates, grouped the two isolates with the X. hortorum pv. carotae M081 strain (Kimbrel et al. 2011) (GenBank accession numbers: MW161270 and MW161271 for atpD for the two isolates, respectively; MW161268 and MW161269 for dnaK; MW161272 and MW161273 for efp). A pairwise identity analysis revealed a 100% identity between all three isolates. Pathogenicity of the isolates was tested by spray inoculation (Christianson et al. 2015) with a bacterial suspension (108 CFU/ml) prepared in sterile distilled water at 3 to 4 true-leaf stage (six plants per isolate). Sterile distilled water was used as negative control. The inoculated plants were incubated in a growth chamber (25°C and 95% relative humidity [RH]) for 72 h, and then transferred to a greenhouse at 24 to 28°C and 65% RH. Characteristic leaf blight symptoms developed on inoculated carrot plants, while no symptoms were observed on the negative control plants 20 days after inoculation. The bacterium was re-isolated from symptomatic tissue and the identity confirmed through PCR analysis. Based on PCR, morphological and phenotypic tests, sequence analysis, and pathogenicity assays, the isolates were identified as X. hortorum pv. carotae. To our knowledge, this is the first report of bacterial leaf blight of carrot caused by X. hortorum pv. carotae in Spain, and the first molecular and pathological characterization. It is important to early detect this pathogen and take suitable measures to prevent its spread, since it could cause yield losses for a locally important crop such as carrot.

scholarly journals First Report of Pseudomonas savastanoi Causing Bacterial Leaf Spot of Mandevilla sanderi in Slovenia

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 415-415 ◽  
Author(s):  
M. Pirc ◽  
M. Ravnikar ◽  
T. Dreo
Keyword(s):  
Uv Light ◽  
Geographical Area ◽  
The United States ◽  
Positive Control ◽  
Hypersensitive Reaction ◽  
Negative Control ◽  
Bacterial Suspension ◽  
First Report ◽  
Systemic Spread ◽  
Necrotic Spots

Foliar necrotic spots with narrow chlorotic halos were observed on different cultivars of Brazilian Jasmine (Mandevilla sanderi) during spring 2010 in several commercial greenhouses in Slovenia. Up to 70% were symptomatic and were unmarketable. No galls were observed on the stems of symptomatic plants. Circular, flat, granulated colonies with entire margins were isolated from symptomatic leaves of two plants from different greenhouses on King's B medium (KB). The isolates were negative for levan, oxidase, pectinolytic and arginine dihydrolase activity. They caused a hypersensitive reaction on tomato but not on tobacco cv. White Burley. Isolates were weakly fluorescent on KB under UV light. One isolate per sample (NIB Z 1413 and 1415) was further characterized. Partial sequences of 16S rDNA (1; GenBank KM603318 of 722 bp, KM603319 of 686 bp) grouped the isolates within genomospecies 2 of Pseudomonas. Repetitive polymerase chain reaction (PCR) assay using the BOXA1R primer (5) resulted in highly similar DNA fragment banding patterns of the two NIB Z isolates and other reference strains of genomospecies 2 (minimum 95.1% identity with Pearson's correlation). Partial sequences of rpoD (3) of the two Slovenian isolates (600 bp; GenBank KJ744202, KJ744201) were identical to the P. savastanoi isolate from Mandevilla B200 (W. Wohanka, Germany; GenBank KJ744203) and P. s. pv. nerii strain NCPPB 3334 (GenBank AB039513). The sequences differed in two nucleotides relative to the sequence of the pathotype strain of pv. nerii NCPPB 3278 (positions 487 and 510 relative to GenBank FN433279) and had an insertion of six nucleotides compared to available P. savastanoi pv. savastanoi rpoD sequences (NZ_JOJV01000073, CM001834). Pathogenicity of isolated bacteria (two isolates) was determined on M. sanderi cv. Pretty Rose inoculated by two different methods, spraying foliage and pricking stems. The abaxial and adaxial surfaces of leaves were sprayed with a 30-ml bacterial suspension (5 × 106 CFU/ml). Three plants were inoculated with each isolate: NIB Z 1413 and 1415 and the reference strain NCPPB 3278. Necrotic spots developed on leaves after 14 days of incubation, under >80% high relative humidity, with 16 h of daylight at 25°C and 8 h of dark at 21°C. One month after inoculation, necrosis also developed on stems and new growth. Inoculation of bacteria by pricking nodes of healthy M. sanderi cv. Pretty Rose with a needle dipped in the isolates grown on KB for 24 h (each of NIB Z 1413, 1415, and NCPPB 3278 for positive control) led to development of galls in 14 days at the inoculation points. The re-isolation was performed separately from necrotic spots on leaves, stems, new growth above the inoculation points, and galls. The BOX-PCR profiles of the bacteria isolated from symptomatic tissues were identical to the original profiles, thus confirming the systemic spread of the bacteria. None of the three negative control plants sprayed with 0.01M MgSO4 or pricked with a sterile needle developed symptoms. This is the first report of P. savastanoi on Mandevilla sanderi plants in greenhouse production in Slovenia. The galls caused by P. savastanoi have previously been reported from the United States (4) and Germany (2). This report broadens the geographical area where P. savastanoi, causing both galls on stems and necrotic spots on leaves, can be found in commercial production of Mandevilla spp. References: (1) U. Edwards et al. Nucleic Acids Res. 17:7843, 1989. (2) N. Eltlbany et al. Appl. Environ. Microbiol. 78:8492, 2012. (3) N. Parkinson et al. Plant Pathol. 60:338, 2011. (4) M. L. Putnam et al. Phytopathology 100:S104, 2010. (5) J. Versalovic et al. Methods Mol. Cell Biol. 5:25, 1994.

scholarly journals First Report of Xanthomonas axonopodis pv. poinsettiicola Causing Bacterial Leaf Spot of Euphorbia pulcherrima in Slovenia

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 70-70 ◽  
Author(s):  
T. Dreo ◽  
M. Pirc ◽  
J. Erjavec ◽  
M. Ravnikar ◽  
I. Miklič-Lautar
Keyword(s):  
Hypersensitive Reaction ◽  
Negative Control ◽  
Leaf Blight ◽  
Economic Damage ◽  
Bacterial Suspension ◽  
Euphorbia Pulcherrima ◽  
Biochemical Tests ◽  
Xanthomonas Axonopodis ◽  
First Report ◽  
Leaf Spots

In September 2009, water-soaked spots, 2 mm in diameter, surrounded by a pale yellow halo were observed on leaves of pot-grown poinsettia plants (Euphorbia pulcherrima L.) cv. Christmas Feeling in a commercial greenhouse in Slovenia. Several spots per leaf developed on 10% of 84 plants used for propagation and slowly progressed to necrotic brown spots. While all plants were watered by overhead irrigation until mid-September, and afterward by flooding, no symptoms were observed on parent plants of four other separately grown cultivars. Propagated cuttings were all grown together, and in addition to cv. Christmas Feeling, an estimated 90% of 315, 35% of 29, 10% of 240, and 5% of 840 plants of cvs. Crazy Marble Star, Crazy Christmas, Lemon Snow, and Cortez Red, respectively, developed leaf spots. Yellow, smooth, and butyrous colonies with entire margins were isolated from symptomatic leaves of poinsettia parent plants of cv. Christmas Feeling on yeast peptone glucose agar (YPGA). They were identified as a Xanthomonas sp. based on biochemical tests (oxidase negative, positive for hydrolysis of H2S, starch and tributiryn and acid production from sucrose) and the isolates caused a hypersensitive reaction in leaves of tomato cv. Moneymaker. Partial sequences of gyrase subunit B-like (gyrB) gene (2) from an isolate (Accession No. HQ215596, 676 bp) showed highest similarity to Xanthomonas axonopodis pv. poinsettiicola strain LMG 5401 (Accession No. GU144264.1, 99% identity, 98% coverage) and 98% identity with gyrB sequence of X. axonopodis pv. poinsettiicola pathotype strain LMG 849 (Accession No. GU144273.1, 99% coverage, 3 gaps). Repetitive BOX-PCR (3) revealed high similarity of our isolate to pathotype strain LMG 849 with one additional band of approximate size of 1,500 bp present in our isolate. The pathogenicity of two isolates from parent plants of cv. Christmas Feeling was confirmed on four young poinsettia plants each. Plants were inoculated with a bacterial suspension of approximate concentration of 106 CFU/ml by spraying on the under side and upper side of the leaves, some of which were pricked with a sterile needle (1). Plants were then incubated under high relative air humidity (minimum 85%), 12 h of daylight, and 25°C day and 20°C night temperature regimens. After 10 days, all inoculated plants developed faint leaf spots, consistent with mild symptoms observed in the greenhouse. Colonies isolated from the developed spots had identical morphology and BOX-PCR profile to original isolates. Mock inoculated, negative control plants did not develop characteristic symptoms and no colonies similar to X. axonopodis pv. poinsettiicola were isolated from them. Bacteria isolated from leaf spots of other poinsettia cultivars had the same biochemical characteristics and BOX-PCR profiles as the first isolate. Since no leaf blight was observed on poinsettias in the greenhouse in the previous season and no host plants were kept between the seasons, imported parent plants are the most likely source of infection. To our knowledge, this is the first report of X. axonopodis pv. poinsettiicola on poinsettia in Slovenia, providing further data on the occurrence and potential economic damage of leaf blight of poinsettia in Europe. References: (1) R. A. Lelliott and D. E. Stead. Host tests. In: Methods in Plant Pathology. Vol 2. Blackwell, Oxford, 1987. (2) N. Parkinson et al. Int. J. Syst. Evol. Microbiol. 59, 264, 2009. (3) J. Versalovic et al. Methods Mol. Cell Biol. 5:25, 1994.

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 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.

scholarly journals Complete and Draft Genome Sequences of the Cruciferous Pathogens Pseudomonas cannabina pv. alisalensis and Pseudomonas syringae pv. maculicola

2021 ◽  
Vol 10 (17) ◽  
Author(s):  
Takashi Fujikawa ◽  
Yuichi Takikawa ◽  
Yasuhiro Inoue
Keyword(s):  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Draft Genome ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Genome Sequences ◽  
Bacterial Leaf Spot ◽  
Content Type

ABSTRACT Pseudomonas cannabina pv. alisalensis and Pseudomonas syringae pv. maculicola cause bacterial leaf blight and bacterial leaf spot of crucifers (Brassicaceae). Both pathogens are threats to the cultivation of cruciferous crops. Here, we sequenced two strains of each pathogen, which will contribute to the development of countermeasures for the above diseases.

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