A REVIEW OF BACTERIAL LEAF SPOT OF PEPPERS (CAPSICUM ANNUUM L.) CAUSED BY XANTHOMONAS CAMPESTRIS PV. VESICATORIA (DOIGE) DYE AND SOME METHODS OF ITS CONTROL

1985 ◽  
pp. 369-376 ◽  
Author(s):  
T. Tegegn
Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1064-1064 ◽  
Author(s):  
I.-S. Myung ◽  
J. Y. Lee ◽  
H. L. Yoo ◽  
J. M. Wu ◽  
H.-S. Shim

In September 2011, bacterial leaf spot was observed on zinnia plants (Zinnia elegans L.) grown in a garden in Suwon, Korea. Leaf symptoms included angular lesions that were yellow or brown-to-reddish brown in the center. Bacterial isolates (BC3293 to BC3299) were recovered on trypticase soy agar from lesions surface-sterilized in 70% ethyl alcohol for 1 min. Pathogenicity of the isolates was confirmed by spray inoculation with a bacterial suspension (106 CFU/ml) prepared in sterile distilled water and applied to zinnia plants at the four- to five-leaf growth stage (two plants per isolate). Sterile distilled water was used as the negative control. The inoculated plants were incubated in a greenhouse at 26 to 30°C and 95% relative humidity. Characteristic leaf spot symptoms developed on inoculated zinnia plants 5 days after inoculation. No symptoms were observed on the negative control plants. The bacterium reisolated from the inoculated leaves was confirmed through gyrB gene sequence analysis (3). All isolates were gram-negative, aerobic rods, each with a single flagellum. Isolates were positive for catalase and negative for oxidase. The biochemical and physiological tests for differentiation of Xanthomonas were performed using methods described by Shaad et al. (2). The isolates were positive for mucoid growth on yeast extract-dextrose-calcium carbonate agar, growth at 35°C, hydrolysis of starch and esculin, protein digestion, acid production from arabitol, and utilization of glycerol and melibiose. Colonies were negative for ice nucleation, and alkaline in litmus milk. The gyrB gene (870 bp) and the 16S-23S rRNA internal transcribed spacer (ITS) regions (884 bp) were sequenced to aid in identification of the original field isolates using published PCR primer sets Xgyr1BF/Xgyr1BR (3) and A1/B1 (1), respectively. Sequence of the gyrB gene (GenBank Accession Nos. JQ665732 to JQ665738) from the zinnia field isolates shared 100% sequence identity with the reference strain of Xanthomonas campestris pv. zinniae (GenBank Accession No. EU285210), and the ITS sequences (GenBank Accession Nos. JQ665725 to JQ665731) had 99.9% sequence identity with X. campestris pv. zinnia XCZ-1 (GenBank Accession No. EF514223). On the basis of the pathogenicity assays, biochemical and physiological tests, and sequence analyses, the isolates were identified as X. campestris pv. zinniae. To our knowledge, this is the first report of bacterial leaf spot of zinnia caused by X. campestris pv. zinniae in Korea. The disease is expected to result in economic and aesthetic losses to plants in Korean landscapes. Thus, seed treatment with bactericides will be required to control the bacterial leaf spot of zinnia before planting. References: (1) T. Barry et al. The PCR Methods Appl. 1:51, 1991. (2) N. W. Schaad et al. Page 189 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. The American Phytopathological Society, St. Paul, MN, 2001. (3) J. M. Young et al. Syst. Appl. Microbiol. 31:366, 2008.


2018 ◽  
Vol 27 (6) ◽  
pp. 30-39
Author(s):  
Loreto Robles-Hernández ◽  
Dámaris Leopoldina Ojeda-Barrios ◽  
Ana Cecilia González-Franco ◽  
Jared Hernández-Huerta ◽  
Nora Aideé Salas-Salazar ◽  
...  

En el presente estudio, 10 aislados bacterianos de chile (Capsicum annuum L.) fueron identificados como Xanthomonas campestris pv. vesicatoria; se determinó su patogenicidad en invernadero y se evaluó su susceptibilidad a Streptomyces lydicus y extractos bioactivos de Ganoderma lucidum en condiciones in vitro y de invernadero, utilizando en cada caso un diseño completamente al azar. Todos los aislados causaron infección con una incidencia del 100% y variaciones en su severidad. Aunque todos los aislados fueron susceptibles a los tratamientos biológicos, los extractos bioactivos fueron superiores con un 100% de inhibición in vitro, así como en la reducción de infección foliar y población bacteriana en invernadero. Destacó una correlación fuerte entre población bacteriana e infección foliar (r = 0.9139**) en plantas inoculadas únicamente con el patógeno; en plantas tratadas adicionalmente con los biológicos, solo hubo una correlación débil en cada caso, sugiriendo su efecto benéfico en la supresión de X. campestris pv. vesicatoria.


2013 ◽  
Vol 80 (2) ◽  
pp. 164-168 ◽  
Author(s):  
Osamu Netsu ◽  
Toshio Kijima ◽  
Yuichi Takikawa

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 186-186 ◽  
Author(s):  
M. L. Lewis Ivey ◽  
S. Wright ◽  
S. A. Miller

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.


HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 745e-745
Author(s):  
Brent Rowell ◽  
Terry Jones ◽  
William Nesmith

Kentucky growers currently produce about 1300 acres of bell peppers worth $2 million for both fresh market and processing. Bacterial leaf spot (BLS) caused by Xanthomonas campestris pv. vesicatoria has been the scourge which continues to limit expansion of pepper production in the state. Fourteen new BLS-resistant varieties and experimental lines were evaluated together with two standard (susceptible) varieties in 1995 at two locations. All entries were exposed to an induced BLS epidemic at one location but were kept disease-free at the second location. Field resistance to four races of BLS was high for all but one of the lines tested, which claimed resistance to races 1, 2, and 3. Cultivars with resistance to only race 2 or races 1 and 2 of the pathogen were no different from susceptible checks in terms of yields and disease resistance. Six entries performed well at both locations; these will be included in further trials in 1996.


Plant Disease ◽  
2013 ◽  
Vol 97 (2) ◽  
pp. 282-282 ◽  
Author(s):  
L. H. Zhou ◽  
G. H. Ji

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.


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