scholarly journals First Report of Bacterial Blight of Crucifers Caused by Pseudomonas cannabina pv. alisalensis in Minnesota on Arugula (Eruca vesicaria subsp. sativa)

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 415-415 ◽  
Author(s):  
C. T. Bull ◽  
M. C. Ortiz-Lytle ◽  
A. G. Ibarra ◽  
L. J. du Toit ◽  
G. Reynolds
Keyword(s):  
Bacterial Blight ◽  
Cropping Systems ◽  
Potassium Phosphate ◽  
Leaf Tissue ◽  
Positive Control ◽  
Hypersensitive Reaction ◽  
Bacterial Strains ◽  
Banding Patterns ◽  
First Report ◽  
Initial Symptoms

In 2011, bacterial blight of arugula (Eruca vesicaria subsp. sativa; cv. Roquette) was observed in organically grown plants under overhead irrigation in a field near Delano, MN. Approximately 80 to 100% of each planting was affected, with greater rates of infection occurring after periods of high humidity. Small, water-soaked, angular spots apparent on both sides of the leaves comprised the initial symptoms, which sometimes expanded and coalesced. Lesions maintained a dark water-soaked appearance or dried and turned a brown/tan color. Additionally, some lesions were outlined by a purple margin. Blue-green fluorescent pseudomonads were isolated consistently on King's Medium B agar (KMB) from symptomatic leaf tissue surface-disinfested with sodium hypochlorite (0.525%). The isolates nucleated ice and produced levan. Isolates were oxidase and arginine dihydrolase negative. They did not rot potato slices but did induce a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliott's LOPAT group 1 (2). DNA fragment banding patterns generated by amplifying DNA of the arugula isolates using repetitive extragenic palindromic sequence–polymerase chain reaction (rep-PCR) and the BOX A1R primer were identical and nearly identical to the banding patterns of the Pseudomonas cannabina pv. alisalensis (formerly P. syringae pv. alisalensis) (1) strain (CFBP1637) and the pathotype strain (CFBP 6866PT), respectively. Pathogenicity was confirmed on the arugula cv. My Way in two independent experiments, each with three replicate plants per treatment. Four isolates were grown on KMB for 48 h at 27°C, suspended in 0.01M potassium phosphate buffer (pH 7.0), and adjusted to 0.6 optical density at 600 nm (approximately 1 × 108 CFU/ml). Five- to six-week old plants were spray-inoculated until run-off, incubated in a humidity chamber for 48 h, and then placed in a greenhouse at 20 to 25°C for symptom development. For negative and positive control treatments, a similar number of plants each were sprayed with sterile buffer or P. cannabina pv. alisalensis strains CFBP1637 and CFBP 6866PT, respectively. Water-soaked and brown/tan lesions similar to the original symptoms appeared on plants inoculated with the arugula isolates and P. cannabina pv. alisalensis strains 7 to 14 days postinoculation. No symptoms developed on plants treated with sterile buffer. The bacterial strains re-isolated from surface-disinfested symptomatic tissue were identical by rep-PCR to the isolates used to inoculate the plants, thus, confirming Koch's postulates. Identical replicated experiments conducted on broccoli raab indicated that the arugula isolates were also pathogens of broccoli raab (Brassica rapa subsp. rapa, the original host from which P. cannabina pv. alisalensis was isolated). To our knowledge, this is the first report of bacterial blight of crucifers caused by P. cannabina pv. alisalensis in Minnesota. Arugula germplasm is being evaluated for resistance to this pathogen as an acceptable management method for organic cropping systems. References: (1) C. T. Bull et al. Syst. Appl. Microbiol. 33:105, 2010. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of the Crucifer Pathogen Pseudomonas cannabina pv. alisalensis Causing Bacterial Blight on Radish (Raphanus sativus) in Germany

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 904-904 ◽  
Author(s):  
I. Rubio ◽  
G. Hiddink ◽  
M. Asma ◽  
C. T. Bull
Keyword(s):  
Pseudomonas Syringae ◽  
Raphanus Sativus ◽  
Bacterial Blight ◽  
Management Strategies ◽  
Leaf Tissue ◽  
Hypersensitive Reaction ◽  
Negative Control ◽  
Banding Patterns ◽  
First Report ◽  
Dna Fragment

In 2008, a bacterial blight was observed on Raphanus sativus in the Pfalz region in Germany. Disease was sporadic but severe when present within R. sativus fields, which resulted in unmarketable crops. Symptoms consisted of small, angular, water-soaked flecks that often were surrounded by chlorotic haloes. Lesions were visible from adaxial and abaxial leaf surfaces and generally retained chlorotic borders. A gram-negative, bluefluorescing bacterium was isolated from surface-disinfested leaf tissue on King's medium B agar. The radish isolate was levan positive, oxidase negative, and arginine dihydrolase negative. The isolate did not rot potato slices but induced a hypersensitive reaction in tobacco. These reactions corresponded to Lelliot's LOPAT group 1 (2). Repetitive extragenic palindromic sequence (rep)-PCR assays using the BOXA1R primer resulted in different DNA fragment banding patterns between the radish isolate and the pathotype strain of Pseudomonas syringae pv. maculicola (CFBP 1657), but identical DNA fragment banding patterns between the radish isolate and the pathotype strain of P. cannabina pv. alisalensis (CFBP 6866). Unlike P. syringae pv. maculicola, P. cannabina pv. alisalensis and the radish isolate were lysed by bacteriophage PBS1 (1). Pathogenicity was evaluated on two hosts, radish (R. sativus cv. Comet) and broccoli raab (Brassica rapa cv. Sorrento). In each of two independent experiments, 3-week-old radish and broccoli raab plants were inoculated with either the radish isolate, P. cannabina pv. alisalensis, or P. syringae pv. maculicola. Inoculum was prepared by growing the bacteria on nutrient agar for 48 h at 27°C, suspending the bacteria in 0.01 M phosphate buffer (pH 7.0), and adjusting each suspension to 0.6 OD at 600 nm (approximately 1 × 108 CFU/ml). All plants were inoculated by spraying until runoff, incubated in a humidity chamber for 48 h, then placed in a greenhouse at 20 to 25°C for symptom development. Plants inoculated with P. cannabina pv. alisalensis or sprayed with buffer served as positive and negative control treatments, respectively. Seven to ten days postinoculation, the development of symptoms similar to those originally observed in the field were observed on plants inoculated with the radish isolate. In addition, symptoms on radish and broccoli raab plants caused by the radish isolate were similar to symptoms caused by P. cannabina pv. alisalensis in contrast to the lack of symptoms on plants inoculated with P. syringae pv. maculicola. Bacteria isolated from symptomatic tissue and surface-disinfested with sodium hypochlorite (0.525%) had identical characteristics to the radish isolate used to inoculate plants and to the P. cannabina pv. alisalensis pathotype for LOPAT reactions, rep-PCR DNA fragment banding pattern analysis, and sensitivity to phage PBS1, thus fulfilling Koch's postulates. To our knowledge, this is the first report of P. cannabina pv. alisalensis isolated from diseased crucifers in Germany. Verification of P. cannabina pv. alisalensis in Germany indicates that German crucifer growers should differentiate between outbreaks caused by P. cannabina pv. alisalensis and P. syringae pv. maculicola and apply appropriate, specific management strategies. References: (1) C. T. Bull et al. Syst. Appl. Microbiol. 33:105, 2010. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Bacterial Blight of Brussels sprouts (Brassica oleracea var. gemmifera) Caused by Pseudomonas cannabina pv. alisalensis in California

Plant Disease ◽  
2010 ◽  
Vol 94 (11) ◽  
pp. 1375-1375 ◽  
Author(s):  
C. T. Bull ◽  
S. J. Mauzey ◽  
S. T. Koike
Keyword(s):  
Brassica Oleracea ◽  
Bacterial Blight ◽  
Positive Control ◽  
Hypersensitive Reaction ◽  
Negative Control ◽  
Brussels Sprouts ◽  
First Report ◽  
Initial Symptoms ◽  
Dna Fragment ◽  
Mist Chamber

Greenhouse-grown Brussels sprouts (Brassica oleracea L. var. gemmifera) transplants from Monterey County, California showed symptoms in 2006 of a previously undescribed disease. Initial symptoms consisted of small (1 to 2 mm in diameter), angular, water-soaked flecks, some of which were surrounded by chlorotic haloes. These flecks coalesced into large, irregularly shaped, gray brown lesions as large as 10 mm. Lesions were visible from both adaxial and abaxial leaf surfaces and generally retained chlorotic borders. This disease resulted in decreased quality and reduced marketability of the transplants. Gram-negative, blue-green fluorescing bacteria were consistently isolated from lesions on King's medium B agar. Ten isolates were selected and used in further studies. Isolates were levan positive, oxidase negative, and arginine dihydrolase negative. Isolates did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum L. cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). Repetitive extragenic palindromic sequence (REP)-PCR using the BOXA1R primer resulted in identical DNA fragment banding patterns for the Brussels sprouts isolates and the pathotype of Pseudomonas cannabina pv. alisalensis (formerly P. syringae pv. alisalensis). Like P. cannabina pv. alisalensis, the isolates from Brussels sprouts were sensitive to bacteriophage PBS1 (1). All 10 isolates were used in two independent pathogenicity experiments. Inoculum for pathogenicity studies was prepared by growing the bacteria on nutrient agar for 48 h (27°C), suspending the bacteria in 0.01 M phosphate buffer (pH 7.0), and adjusting each suspension to 0.6 OD at 600 nm (approximately 108 CFU/ml). In each experiment, six Brussels sprouts plants were inoculated for each isolate by spraying until runoff or by swabbing a suspension of the appropriate bacterial isolate to which Carborundum had been added. Additionally, four Brussels sprouts isolates were used to spray inoculate six broccoli raab (Brassica rapa subsp. rapa) plants. Positive control plants were inoculated with the pathotype of P. cannabina pv. alisalensis, and the negative control plants were inoculated with sterile buffer or sterile buffer with Carborundum. Inoculated plants were placed in a mist chamber for 48 h and then in a greenhouse (20 to 25°C). After 5 to 7 days, foliar symptoms similar to symptoms observed on the original diseased Brussels sprouts plants developed on all inoculated plants, including the positive control plants inoculated with P. cannabina pv. alisalensis. Negative control plants remained symptomless. In each experiment, bacteria reisolated from symptomatic tissue were identical to the bacteria used to inoculate the plants and to P. cannabina pv. alisalensis for LOPAT reactions, REP-PCR DNA fragment banding pattern, and sensitivity to phage PBS1. To our knowledge, this is the first report of P. cannabina pv. alisalensis causing bacterial blight of Brussels sprouts. References: (1) C. T. Bull et al. Syst. Appl. Microbiol. 33:105, 2010. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Blossom Blight of Strawberry (Fragaria × ananassa) Caused by Pseudomonas marginalis

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1350-1350 ◽  
Author(s):  
C. T. Bull ◽  
A. I. Huerta ◽  
S. T. Koike
Keyword(s):  
Phosphate Buffer ◽  
Methyl Esters ◽  
Hypersensitive Reaction ◽  
Fluorescent Pseudomonad ◽  
Fragaria Ananassa ◽  
Banding Patterns ◽  
First Report ◽  
Incidence Data ◽  
Initial Symptoms ◽  
Green Fluorescent

In 2003, a new disease was observed on commercial strawberries (Fragaria × ananassa Duch.) grown in multiple fields in Watsonville, CA. Initial symptoms consisted of brown lesions on the undersides of the sepals of strawberry flowers. The lesions coalesced and spread to upper sepal surfaces and anther bases. No leaf symptoms were observed. Fields affected with this disease appeared to have a greater number of deformed fruit, though incidence data were not collected. A gram-negative, blue-green fluorescent pseudomonad was isolated from lesions on King's medium B agar from both sepals and anthers from 23 of 24 samples from three different fields. All isolates were levan, oxidase, and arginine dihydrolase positive. The strains did rot potato slices but did not induce a hypersensitive reaction in tobacco (Nicotiana tabacum L. cv. Sansun), indicating that the bacteria belonged to Lelliot's LOPAT group IVa, P. marginalis (3). Isolates from strawberry were compared with pathotype strains of Pseudomonas marginalis pv. marginalis, P. marginalis pv. alfalfae, and P. marginalis pv. pastinaceae. The 16S rDNA sequence of type strain of P. marginalis (Z76663) was 97 to 99% similar to the four strawberry isolates sequenced (GQ845121). Identity was further supported by analysis of fatty acid methyl esters (MIS-TSBA version 4.10; MIDI, Inc., Newark, DE). Polymerase chain reaction using BOX-A1R primers (repetitive sequence-based (rep)-PCR [1]) resulted in DNA fragment banding patterns that were identical among strawberry isolates. These banding patterns were different from the three distinct patterns of the P. marginalis pathotypes. Pathogenicity on strawberry (cv. Albion) was confirmed in three experiments using four strawberry isolates originally isolated from plants from three different fields and the P. marginalis pathotype strains. Inoculum was produced by growing bacteria in nutrient broth shake cultures for 48 h (24°C) and washing and suspending the cultures in 0.01 M phosphate buffer (pH 7.0). Three to five attached strawberry flowers on separate plants were dipped in the bacterial suspensions (106 CFU/ml) or sterile buffer for 1 min. To maintain high humidity, flower buds were enclosed in plastic bags for 36 to 48 h and then incubated in the greenhouse (24 to 26°C). After 7 days, approximately half of the flowers inoculated with the strawberry isolates had symptoms on sepals that were identical to symptoms seen in the field. Additionally, reisolates obtained from the symptomatic, inoculated flowers were identical to those used to inoculate the plants as confirmed by LOPAT reactions and rep-PCR, thus completing Koch's postulates. Flowers dipped in phosphate buffer or the P. marginalis pathotype strains did not develop symptoms and no bacteria were reisolated. To our knowledge, this is the first report of blossom blight of strawberry caused by P. marginalis and the first report of P. marginalis on strawberry in California. P. marginalis causes leaf bud rot of strawberry in Japan (2). Further research is needed to determine if the strawberry isolates represent a new or previously described pathovar of P. marginalis. References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) T. Kijima et al. Bull. Tochigi. Agric. Exp. Stn. 36:59, 1989. (3) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Bacterial Blight of Cabbage (Brassica oleracea var. capitata) Caused by Pseudomonas cannabina pv. alisalensis in California

Plant Disease ◽  
2011 ◽  
Vol 95 (1) ◽  
pp. 71-71 ◽  
Author(s):  
S. J. Mauzey ◽  
S. T. Koike ◽  
C. T. Bull
Keyword(s):  
Brassica Oleracea ◽  
Phosphate Buffer ◽  
Bacterial Blight ◽  
Positive Control ◽  
Negative Control ◽  
Tween 20 ◽  
First Report ◽  
Initial Symptoms ◽  
Dna Fragment ◽  
Negative Controls

In 2008, field-grown cabbage (Brassica oleracea var. capitata L., cv. Grenader) from Monterey County, California showed symptoms on the wrapper leaves of immature plants that had formed heads. Initial symptoms consisted of small, brown, water-soaked flecks surrounded by chlorotic haloes. These flecks later coalesced into large, irregularly shaped, brown-black, necrotic lesions with chlorotic haloes visible on both adaxial and abaxial surfaces of the leaf. This disease resulted in lower quality and reduced marketability of the cabbage. Five gram-negative, blue-green fluorescing bacteria were isolated from separate lesions on different plants on King's medium B agar. The isolates were positive for levan formation and negative for oxidase and arginine dihydrolase. The isolates did not cause soft rot on potato slices but did induce a hypersensitive reaction in tobacco (Nicotiana tabacum L. cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). Repetitive extragenic palindromic sequence (rep)-PCR using the BOXA1R primer resulted in identical DNA fragment banding patterns for the cabbage isolates and the pathotype of Pseudomonas cannabina pv. alisalensis (formerly P. syringae pv. alisalensis). Additionally, both P. cannabina pv. alisalensis and the five cabbage isolates were sensitive to bacteriophage PBS1 while the pathotype strain of P. syringae pv. maculicola was not (1). Pathogenicity of the five cabbage isolates was evaluated in two independent experiments. Inoculum was prepared by growing the bacteria on nutrient agar for 48 h (27°C), suspending the bacteria in 0.01 M phosphate buffer (pH 7.0), adjusting each suspension to 0.6 OD at 600 nm (approximately 108 CFU/ml), and adding three to five drops of Tween 20. In each experiment, two cabbage, broccoli raab (Brassica rapa subsp. rapa cv. Sorrento), and oat (Avena sativa cv. Montezuma) plants were inoculated for each isolate by spraying until runoff. Positive control plants were inoculated with the pathotype strain of P. cannabina pv. alisalensis and negative control plants were treated with sterile 0.01 M phosphate buffer. The plants were placed in a mist chamber for 48 to 72 h and then in a greenhouse (20 to 25°C). After 7 to 10 days, foliar symptoms similar to symptoms observed on the original diseased cabbage plants developed on all inoculated plants including the positive control plants inoculated with P. cannabina pv. alisalensis. Additionally severe symptoms on broccoli raab and minor symptoms on oats developed on plants inoculated with cabbage strains or P. cannabina pv. alisalensis. For each experiment, bacteria reisolated from symptomatic tissue were identical to the bacteria used to inoculate the plants and to P. cannabina pv. alsialensis for rep-PCR DNA fragment banding pattern and sensitivity to phage PBS1. There were no symptoms on any of the cabbage and oat negative controls. Additionally, there were no symptoms on any broccoli raab negative controls in the first experiment; however, in the second experiment, a small (<1 mm) lesion was detected on one leaf of one plant. To our knowledge, this is the first report of P. cannabina pv. alisalensis causing bacterial blight of cabbage in California. This disease may have significant impact because of the large acreage of cabbage grown in California (approximately 5,666 ha annually). References: (1) C. T. Bull et al. Syst. Appl. Microbiol. 33:105, 2010. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

scholarly journals First Report of Xanthomonas hortorum pv. hederae Causing Bacterial Leaf Spot of Hedera hibernica in Slovenia

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 141-141 ◽  
Author(s):  
M. Pirc ◽  
T. Dreo ◽  
M. Šuštaršič ◽  
J. Erjavec ◽  
M. Ravnikar
Keyword(s):  
Type Strain ◽  
Negative Control ◽  
The European Union ◽  
Bacterial Strains ◽  
Biochemical Tests ◽  
Adaxial Side ◽  
Banding Patterns ◽  
First Report ◽  
Dna Fragment ◽  
Pale Green

In October 2008, water-soaked spots, each 5 to 10 mm in diameter and surrounded by a pale green halo, were observed on leaves of a single Atlantic ivy plant (Hedera hibernica Kirchn.) out of 89 plants imported from the European Union into a commercial greenhouse in Slovenia. Leaves were surface disinfected, and spots were cut and suspended in 10 mM phosphate buffered saline. From this extract, yellow-pigmented, Xanthomonas-like bacterial colonies were isolated onto nutrient agar, and two colonies (NIB Z 1310 and NIB Z 1312) were each identified as a Xanthomonas sp. based on biochemical tests (oxidase negative; positive for hydrolysis of H2S, starch, and tributyrin; and positive for acid production from sucrose). Both isolates caused a hypersensitive reaction (1) on leaves of tomato cv. Moneymaker. A repetitive extragenic palindromic sequence (REP)-PCR assay using the BOXA1R primer (3) resulted in highly similar DNA fragment banding patterns (Pearson's correlation: 95% identity) between the two isolates (NIB Z 1310 and NIB Z 1312) and the type strain of Xanthomonas hortorum pv. hederae CFBP 4925 (ICMP 453). Partial sequences of the gyrB gene (DNA gyrase, subunit B) (2) from isolates NIB Z 1310 (Accession No. JF794785; 599 bp) and NIB Z 1312 (Accession No. JF794784; 544 bp), showed identical sequences (100% identity with 100% coverage) to type strain ICMP 453 (Accession No. EU498975.1). The pathogenicity of the two isolates from H. hibernica was confirmed on three plants of H. helix ‘Evita’ (each 6 months old) for each isolate. Plants were sprayed on the abaxial and adaxial side of leaves with 10 ml of a 48-h suspension of the appropriate isolate with approximately 106 CFU/ml (1), covered individually with plastic bags for 24 h, and incubated under high relative humidity (>80%) with 16 h of daylight at 25°C by day and 20°C by night. Three positive and three negative control plants were inoculated with the type strain of X. hortorum pv. hederae CFBP 4925 and 0.01 M magnesium sulfate buffer, respectively. After 21 days, water-soaked spots with a pale green halo were observed on all plants inoculated with the bacterial strains, including the positive control plants. Colonies isolated from these lesions were identical in morphology and BOX-PCR DNA fragment banding patterns to the original isolates. Negative control plants did not develop symptoms, and colonies similar to X. hortorum pv. hederae were not isolated from these plants. To our knowledge, this is the first report of X. hortorum pv. hederae on H. hibernica in greenhouse production in Slovenia. If the disease spreads, it could reduce quality and marketability of this popular ground cover plant. References: (1) Z. Klement et al. Inoculation of Plant Tissues. In: Methods in Phytobacteriology. Akadémiai Kiadó, Budapest, 1990. (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.

scholarly journals First Report of Bacterial Leaf Spot of Rieger Begonia Caused by Xanthomonas campestris pv. begoniae in China

Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 282-282 ◽  
Author(s):  
L. H. Zhou ◽  
G. H. Ji
Keyword(s):  
Leaf Spot ◽  
Xanthomonas Campestris ◽  
Infection Process ◽  
Leaf Spot Disease ◽  
Leaf Margin ◽  
Bacterial Strains ◽  
Bacterial Leaf Spot ◽  
First Report ◽  
Initial Symptoms ◽  
Phosphate Buffered Saline

Rieger begonia are collectively referred to as a begonia hybrid group. Its global annual sales is 90,000,000 cutting seedlings. It is one of the top ten potted plants. In the summer of 2011, serious outbreaks of a suspected bacterial leaf spot disease were observed on five Rieger begonia cultivars (Dark Britt, Rebecca, Blitz, Barkos, and Borias). These plants were grown for potted cutting seedling production in commercial nurseries located in Shilin county of Yunnan Province, China. The initial symptoms of the disease were small circular or polygonal water-soaked needle spots on leaf margin that later these spots expanded and joined together, forming bigger inverted V-shaped necrotic specks (4). Yellow-pigmented bacterial colonies were consistently isolated from diseased leaves and stems on NA agar medium and incubated at 28°C. Twelve bacterial strains were isolated and used for further studies. All the isolates were Gram-negative, rod-shaped, motile, aerobic, and non-sporing. All of the bacterial strains isolated in the present study were identified as Xanthomonas campestris pv. begoniae (Xcb) based on biochemical and physiological identification (Biolog carbon source utilization analysis) and 16S rDNA sequences analysis and further pathogenicity determination (1). The results show that the sequence homology rate of HT1-1 (GenBank Accession No. JN648097) and X. euvesicatoria (syn. X. campestris pv vesicatoria) (GeneBank Accession No. AM039952) is 99%. This strongly suggests that the Rieger begonia isolates belong to X. campestris pv. begoniae (2). For Koch's postulates, 10 surface-disinfected young leaves from five susceptible Rieger begonia plants (cv. Dark Britt) were inoculated by spraying a phosphate-buffered saline suspension of each bacterial isolate (3.0 × 108 CFU/ml) onto the leaves (3). Controls were inoculated similarly with phosphate-buffered saline solution. All inoculated plants were covered with polyethylene bags for 24 h at 25°C and then put in the greenhouse. After inoculation, water-soaked and necrotic symptoms were observed on inoculated Rieger begonia leaves within 7 to 9 days. No symptoms were observed on controls. Bacteria were reisolated and confirmed to be identical to the original isolates by the methods described above. To our knowledge, this is the first report of Xcb causing leaf spot on Rieger begonia plants in China. The infection process of Xcb on Rieger begonia plants and rapid detection of this pathogen are underway. References: (1) M. R. Gillings et al. PNAS 12:102, 2005. (2) C. L. Oliver et al. Plant Dis. 4:96, 2012. (3) H. Ornek et al. New Dis. Rep. 13:40, 2006. (4) O. Pruvost et al. Plant Dis. 4:96, 2012.

scholarly journals First Report of Bean Leafroll Luteovirus Infecting Pea in Italy

Plant Disease ◽  
1999 ◽  
Vol 83 (4) ◽  
pp. 399-399 ◽  
Author(s):  
R. C. Larsen ◽  
D. M. Webster
Keyword(s):  
Nucleic Acid ◽  
Faba Bean ◽  
Acyrthosiphon Pisum ◽  
Sequence Data ◽  
Potassium Phosphate ◽  
Leaf Tissue ◽  
Po River ◽  
First Report ◽  
Access Period ◽  
Pea Aphids

Approximately 5,000 ha of processing peas (Pisum sativum L) are cultivated annually in the Po River Valley of northern Italy. During the 1998 growing season, affected pea plants in this region were observed that exhibited mild chlorosis and mottling, leaf rolling, and stunting symptoms. High aphid populations and disease levels of nearly 100% were observed in susceptible varieties. Samples from affected fields were analyzed for the presence of bean leafroll virus (BLRV). Nonviruliferous pea aphids (Acyrthosiphon pisum Harris) received a 48-h acquisition access period on symptomatic leaves. Aphids were then transferred to Puget pea and Diana faba bean for a 72-h inoculation access period. Leaf samples were also macerated in 0.05 M potassium phosphate pH 7.4, and inoculated mechanically to pea, faba bean, chickpea (Cicer arietinum L.), Chenopodium quinoa Willd., and C. amaranticolor Coste & Reyn. Symptoms typical of those observed in the original field plants appeared 10 to 14 days after aphid transmissions in both pea and faba bean inoculated with pea aphids. No symptoms were observed in any of the hosts that were inoculated mechanically. Total nucleic acid extracts from the original pea samples, and from leaf tissue of pea and faba bean plants inoculated with aphids, served as templates in reverse-transcriptase polymerase chain reaction assays. Primers BLR-V157 and BLR-C546, which flanked a 400-bp fragment, were designed with available sequence data for the coat protein gene of BLRV (1). An amplification product of the expected size was generated from symptomatic plants but not from healthy controls. Sequence analysis of the cloned fragments revealed a 99% nucleic acid homology with the published sequence for BLRV and an isolate obtained from alfalfa in Washington State (R. Larsen, unpublished). This is the first report of BLRV in Italy. Reference: (1) B. Brill et al. Nucleic Acids Res. 18:5544, 1990.

scholarly journals First Report of Fire Blight Caused by Erwinia amylovora on Meadowsweet (Spirea prunifolia) in Turkey

Plant Disease ◽  
2014 ◽  
Vol 98 (1) ◽  
pp. 153-153 ◽  
Author(s):  
K. K. Bastas ◽  
F. Sahin
Keyword(s):  
Pathogenic Bacteria ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Natural Infection ◽  
Hypodermic Needle ◽  
Identification System ◽  
Bacterial Strains ◽  
First Report ◽  
Molecular Tests ◽  
Initial Symptoms

Fire blight, caused by Erwinia amylovora (Burr.) Winslow et al., affects plants in the Rosaceae family, which includes trees and shrubs in orchards, nurseries, and landscape plantations. During the springs and summers of 2008 and 2010, dying branches, necrotic leaves attached to shoots, and blighted twigs of meadowsweet (Spirea prunifolia) were observed at three different locations of landscape areas in Konya Province, Turkey. Disease incidence was approximately 1% on the plants during the surveys. Initial symptoms of reddish to brownish streaks on the shoots of infected plants were observed in spring. Nine representative bacterial strains were isolated from the lesions on shoots of seven meadowsweet plants on nutrient sucrose agar (NSA) medium and identified as E. amylovora on basis of biochemical, physiological (2,3) and molecular tests (1). Bacteria were gram-negative, rod shaped, aerobic, fermentative, yellow-orange on Miller and Scroth medium (2), positive for levan formation and acetoin production, did not grow at 36°C, positive for gelatin hydrolysis, and negative for esculin hydrolysis, indole, urease, catalase, oxidase, arginine dehydrolase, reduction of nitrate, acid production from lactose, and inositol. All strains were hypersensitive response-positive on tobacco (Nicotiana tabacum var. White Burley) plants. All strains were identified as E. amylovora using the species-specific primers set, A/B (1), by PCR assay, and by fatty acid methyl ester (FAME) profiles determined by Sherlock Microbial Identification System software (TSBA 6 v. 6.00; Microbial ID, Newark, DE) with similarity indices ranging from of 79 to 99%. Pathogenicity was tested by injecting of petioles and actively growing three shoot tips of 2-year-old S. prunifolia seedlings cv. number 29 using a 0.46 mm-diameter hypodermic needle with bacterial suspensions containing 108 CFU mL–1 in sterile distilled water (SDW) Plants were inoculated with each of the nine bacterial strains and two references strains, Ea29 and NCPPB 2791 (Selcuk University, Department of Plant Protection, Konya, Turkey). Symptoms resembling those associated with natural infection appeared on the inoculated plants 7 days after inoculation. Plants inoculated with SDW served as a negative control treatment, and no symptoms were observed on these plants. All tests were repeated three times with the same results. Bacterial re-isolations were attempted from the control plants as well as shoots and leaves inoculated with the two reference strains and the nine bacteria identified as E. amylovora. Bacteria isolated from inoculated plants were identified as E. amylovora using the biochemical, physiological, and molecular tests described above, but this bacterium was not isolated from the control plants. Phytosanitary measures must be taken to avoid spread of the pathogen to ornamentals in new landscape areas in Turkey. This report is important because infected Spirea spp. can be a potential inoculum source for other rosaceous ornamentals. To our knowledge, this is the first report of the occurrence of fire blight on meadowsweet in Turkey. References: (1) S. Bereswill et al. Appl. Environ. Microbiol. 58:3522, 1992. (2) A. L. Jones and K. Geider. Laboratory Guide for Identification of Plant Pathogenic Bacteria, pp. 40-55. American Phytopathological Society, St. Paul, MN, 2001. (3) R. A. Lelliott and D. E. Stead. Methods for Diagnosis of Bacterial Diseases of Plants (Methods in Plant Pathology). Oxford, UK, 1987.

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 First Report of Bacterial Blight of Crucifers Caused by Pseudomonas cannabina pv. alisalensis in Australia

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 1027-1027 ◽  
Author(s):  
C. T. Bull ◽  
I. Rubio
Keyword(s):  
Pseudomonas Syringae ◽  
Phosphate Buffer ◽  
Bacterial Blight ◽  
Control Treatment ◽  
Wagga Wagga ◽  
Bacterial Disease ◽  
Banding Patterns ◽  
First Report ◽  
Dna Fragment ◽  
Buffer Control

In 1978 and 1979, Pseudomonas syringae pv. maculicola strains DAR 33362, DAR 33363, and DAR 33406 were isolated from diseased Brassica hirta, B. nigra, and B. napus var. napus, respectively, in Wagga Wagga and Armatree, NSW, Australia (2). Peters et al. (2) demonstrated that these strains were similar to P. syringae pv. maculicola ICMP 4326 (CFBP 1637), which was recently transferred to Pseudomonas cannabina pv. alisalensis (1). We evaluated these Australian strains to determine if they might also be P. cannabina pv. alisalensis. Amplification of DNA using the BOXA1R primer and PCR resulted in identical DNA fragment banding patterns for Australian strains DAR 33362 and DAR 33363 and P. cannabina pv. alisalensis ICMP 4326 and CFBP 6875. The third Australian strain, DAR 33406, was 90% similar to P. cannabina pv. alisalensis; in contrast, it was only 77% similar to P. syringae pv. maculicola. All strains of P. cannabina pv. alisalensis, including the pathotype strain (CFBP 6866) and all three Australian strains, were lysed by bacteriophage PBS1, which is specific for P. cannabina pv. alisalensis strains (1). To complete Koch's postulates, pathogenicity was evaluated on B. hirta, B. nigra, and B. napus var. napus. In two independent experiments, two plants of each species were inoculated with each Australian strain or a phosphate buffer control treatment. In separate experiments, pathogenicity was evaluated on the differential hosts radish (Raphanus sativus cv. Comet) and broccoli raab (Brassica rapa cv. Sorrento), and plants inoculated with the pathotypes of P. cannabina pv. alisalensis and P. syringae pv. maculicola served as additional control treatments. Inoculum was prepared by growing the bacteria on nutrient agar for 48 h (27°C), suspending the bacteria in 0.01 M phosphate buffer (pH 7.0), and adjusting each suspension to 0.6 OD at 600 nm (approximately 108 CFU/ml). Treatments were applied by spraying until runoff. DAR 33362, DAR 33363, and DAR 33406 caused typical bacterial blight symptoms on B. hirta, B. nigra, and B. napus var. napus. Infected leaves became yellow, followed by the development of small (<2 mm in diameter), angular, water-soaked, and eventually, shot-holed spots. Bacteria isolated from symptomatic tissue following surface disinfestation of tissue with sodium hypochlorite (0.525%) had identical characteristics (rep-PCR DNA fragment banding patterns and phage sensitivity) to the strains used to inoculate the plants. Additionally, DAR 33362, DAR 33363, and DAR 33406, as well as P. cannabina pv. alisalensis, caused symptoms on radish and broccoli raab while P. syringae pv. maculicola and the buffer control did not. These data support the transfer of the Australian crucifer strains, originally identified as P. syringae pv. maculicola, to P. cannabina pv. alisalensis. To our knowledge, this is the first report of a bacterial disease of crucifers caused by P. cannabina pv. alisalensis in Australia. Differentiation of these pathogens will inform crop rotation strategies for disease management. References: (1) C. T. Bull et al. Syst. Appl. Microbiol. 33:105, 2010. (2) B. J. Peters et al. Plant Pathol. 53:3, 2004.

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