scholarly journals Recent Outbreaks of Black Rot of Brassicas Caused by Xanthomonas campestris pv. campestris in Southern Mozambique

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1218-1218
Author(s):  
J. Bila ◽  
A. M. Mondjana ◽  
E. G. Wulff ◽  
C. N. Mortensen
Keyword(s):  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Identification System ◽  
Black Rot ◽  
Microbial Identification ◽  
Brassica Spp ◽  
Brassica Crop ◽  
Leaf Tissues ◽  
Pathogenicity Tests ◽  
Xanthomonas Campestris Pv Campestris

In August and September of 2007, black rot symptoms were observed on seedbed and field plants of Brassica spp. grown in the southern districts of Boane, Mahotas, and Chòkwé in Mozambique. One hundred eighty-two cabbage-growing households were evaluated for the incidence of Xanthomonas campestris pv. campestris. Five Brassica cultivars, Glory F1, Glory of Enkhuizen, Copenhagen Market, Starke (Brassica oleracea pv. capitata L.), and Tronchuda (B. oleracea L. var. costata DC) were grown in the areas for several years. The hybrid Glory F1 was the most popular grown cultivar in the surveyed areas. In the Boane district, the highest incidence of black rot was recorded on Copenhagen Market (70%), Starke (67.9%), and Glory F1 (67.3%). In Chòkwé, Tronchuda (Portuguese kale) was the least affected Brassica crop. Water-soaked lesions starting at the edge of leaves with typical V-shaped necrotic lesions and vein discoloration were the most commonly observed symptoms. When examined with a microscope, cut edges of symptomatic stem and leaf tissues consistently exhibited bacterial streaming. The bacteria were isolated from commercial seed and field-grown plants on semiselective agar media (2). Forty-six X. campestris pv. campestris strains that were gram negative, aerobic, starch positive, nitrate negative, and oxidase negative or weakly positive (3) were further identified on the basis of ELISA (Agdia Inc., Elhart, IN), GN Biolog Microbial Identification System, version 4.2 (Biolog Inc., Hayward, CA), and PCR-specific primers (1). Pathogenicity tests were conducted by pin inoculating two upper leaves of cabbage (cv. Wirosa) in the 2- to 3-leaf stage with bacterial growth from 24-h-old agar cultures (2). Black rot symptoms developed on nearly all inoculated plants within 7 to 14 days. No symptoms were observed on control plants inoculated with a sterile pin without bacterial inoculum. The severity of black rot of Brassica spp. in three important farming districts caused significant losses in Mozambique. References: (1) T. Berg et al. Plant Pathol. 54:416, 2005. (2) S. J. Roberts and H. Koenraadt. Page 1 in: International Rules for Seed Testing: Annexe to Chapter 7 Seed Health Methods. ISTA, 2007. (3) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001.

scholarly journals Occurrence and Diversity of Xanthomonas campestris pv. campestris in Vegetable Brassica Fields in Nepal

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Brita Dahl Jensen ◽  
Joana G. Vicente ◽  
Hira K. Manandhar ◽  
Steven J. Roberts
Keyword(s):  
Xanthomonas Campestris ◽  
Mustard Seed ◽  
Black Rot ◽  
Brassica Spp ◽  
Mustard Plant ◽  
Race 1 ◽  
Polymerase Chain ◽  
Race 4 ◽  
Xanthomonas Campestris Pv Campestris ◽  
Vegetable Brassica

Black rot caused by Xanthomonas campestris pv. campestris was found in 28 sampled cabbage fields in five major cabbage-growing districts in Nepal in 2001 and in four cauliflower fields in two districts and a leaf mustard seed bed in 2003. Pathogenic X. campestris pv. campestris strains were obtained from 39 cabbage plants, 4 cauliflower plants, and 1 leaf mustard plant with typical lesions. Repetitive DNA polymerase chain reaction-based fingerprinting (rep-PCR) using repetitive extragenic palindromic, enterobacterial repetitive intergenic consensus, and BOX primers was used to assess the genetic diversity. Strains were also race typed using a differential series of Brassica spp. Cabbage strains belonged to five races (races 1, 4, 5, 6, and 7), with races 4, 1, and 6 the most common. All cauliflower strains were race 4 and the leaf mustard strain was race 6. A dendrogram derived from the combined rep-PCR profiles showed that the Nepalese X. campestris pv. campestris strains clustered separately from other Xanthomonas spp. and pathovars. Race 1 strains clustered together and strains of races 4, 5, and 6 were each split into at least two clusters. The presence of different races and the genetic variability of the pathogen should be considered when resistant cultivars are bred and introduced into regions in Nepal to control black rot of brassicas.

scholarly journals First Report of Black Rot of Cauliflower and Kale Caused by Xanthomonas campestris pv. campestris in Yugoslavia

Plant Disease ◽  
1999 ◽  
Vol 83 (10) ◽  
pp. 965-965 ◽  
Author(s):  
A. Obradović ◽  
M. Arsenijević
Keyword(s):  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Black Rot ◽  
Triphenyl Tetrazolium Chloride ◽  
American Phytopathological Society ◽  
Tetrazolium Chloride ◽  
Gram Negative ◽  
First Occurrence ◽  
Dark Green ◽  
Xanthomonas Campestris Pv Campestris

In Yugoslavia, Xanthomonas campestris pv. campestris was isolated from forage kale in 1964 and cabbage in 1997 (1). Recently, the incidence and severity of black rot symptoms on cabbage, cauliflower, and kale have increased. Gram-negative, rod-shaped, motile bacteria were isolated from the diseased leaf and vascular tissues of cauliflower and kale plants collected from 1995 to 1998. The isolates formed yellow, convex, mucoid colonies on yeast dextrose chalk medium, metabolized glucose oxidatively, grew at 37°C, hydrolyzed gelatin and esculin, produced acids from d-arabinose, glucose, sucrose, and trehalose, and did not reduce nitrates. They were nonfluorescent, amylolytic and pectolytic, oxidase negative and catalase positive, and tolerant to 5% NaCl but not to 0.1% triphenyl tetrazolium chloride. Koch's postulates were completed by injecting bacterial suspensions (108 CFU/ml) into leaf petioles of cabbage, cauliflower, and kale seedlings (2- to 3-leaf stage). Dark green watersoaking of petioles and leaf veins followed by yellowing and collapse of inoculated plants was observed after 3 to 5 days. When compared with published information (2), the isolates were identified as X. campestris pv. campestris. This is the first occurrence of this bacterium in cauliflower and kale in Yugoslavia. References: (1) O. Jovanovic et al. Plant Prot. Belgrade 221:175, 1997. (2) N. W. Schaad. 1988. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 2nd ed. The American Phytopathological Society, St. Paul, MN.

scholarly journals First Report of Black Rot on Arugula Caused by Xanthomonas campestris pv. campestris in Argentina

Plant Disease ◽  
2008 ◽  
Vol 92 (6) ◽  
pp. 980-980 ◽  
Author(s):  
A. M. Romero ◽  
R. Zapata ◽  
M. S. Montecchia
Keyword(s):  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Biochemical Characterization ◽  
Bacterial Suspension ◽  
Black Rot ◽  
Strictly Aerobic ◽  
First Report ◽  
Plastic Bags ◽  
Water Plants ◽  
Xanthomonas Campestris Pv Campestris

During the fall of 2005, arugula (Eruca sativa Mill.) plants grown in experimental field plots in Buenos Aires, Argentina presented V-shaped necrotic lesions on leaf margins and blackened veins with broad yellow halos, followed by leaf necrosis. At flowering, 96% of the plants were affected with 27% of the leaves with symptoms. Yellow, round, mucoid, convex, bacterial colonies were isolated from several leaves on yeast dextrose chalk agar. Two strains were further studied. Xanthomonas campestris pv. campestris Xcc8004 was used as a control. Strains were gram negative, rod shaped, strictly aerobic, catalase-positive, oxidase and urease-negative, hydrolyzed starch, gelatine and aesculin, and did not reduce nitrate (2). Pathogenicity was tested by spraying 10 3-week-old arugula plants with either a bacterial suspension (107 CFU/ml) or sterile water. Plants were placed in plastic bags for 72 h after inoculation. All inoculated plants showed necrotic lesions enlarging from the margin of the leaves 7 days after inoculation. No lesions were observed on control plants. On the basis of biochemical characterization (2) and genomic fingerprints generated by BOX-PCR (1), the pathogen was identified as X. campestris pv. campestris. To our knowledge, this is the first report of X. campestris pv. campestris causing black rot on arugula in Argentina. References: (1) J. L. Rademaker et al. Int. J. Syst. Evol. Microbiol. 50:665, 2000. (2) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001.

scholarly journals Genetic Diversity and Population Structure of the Xanthomonas campestris pv. campestris Strains Affecting Cabbages in China Revealed by MLST and Rep-PCR Based Genotyping

2021 ◽  
Vol 37 (5) ◽  
pp. 476-488
Author(s):  
Guo Chen ◽  
Congcong Kong ◽  
Limei Yang ◽  
Mu Zhuang ◽  
Yangyong Zhang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Xanthomonas Campestris ◽  
Resistance Breeding ◽  
Black Rot ◽  
Yield Losses ◽  
Mlst Analysis ◽  
Pathogen Diversity ◽  
Pathogenicity Tests ◽  
Xanthomonas Campestris Pv Campestris

<i>Xanthomonas campestris</i> pv. <i>campestris</i> (<i>Xcc</i>) is the causal agent of black rot for cruciferous vegetables worldwide, especially for the cole crops such as cabbage and cauliflower. Due to the lack of resistant cabbage cultivars, black rot has brought about considerable yield losses in recent years in China. Understanding of the pathogen features is a key step for disease prevention, however, the pathogen diversity, population structure, and virulence are largely unknown. In this study, we studied 50 <i>Xcc</i> strains including 39 <i>Xcc</i> isolates collected from cabbage in 20 regions across China, using multilocus sequence genotyping (MLST), repetitive DNA sequence-based PCR (rep-PCR), and pathogenicity tests. For MLST analysis, a total of 12 allelic profiles (AP) were generated, among which the largest AP was AP1 containing 32 strains. Further cluster analysis of rep-PCR divided all strains into 14 DNA groups, with the largest group DNA I comprising of 34 strains, most of which also belonged to AP1. Inoculation tests showed that the representative <i>Xcc</i> strains collected from diverse regions performed differential virulence against three brassica hosts compared with races 1 and 4. Interestingly, these results indicated that AP1/DNA I was not only the main pathotype in China, but also a novel group that differed from the previously reported type races in both genotype and virulence. To our knowledge, this is the first extensive genetic diversity survey for <i>Xcc</i> strains in China, which provides evidence for cabbage resistance breeding and opens the gate for further cabbage-<i>Xcc</i> interaction studies.

Improved control of black rot of broccoli caused by Xanthomonas campestris pv. campestris using a bacteriophage and a nonpathogenic Xanthomonas sp. strain

2017 ◽  
Vol 83 (6) ◽  
pp. 373-381 ◽  
Author(s):  
Hirofumi Nagai ◽  
Noriyuki Miyake ◽  
Shinro Kato ◽  
Daisuke Maekawa ◽  
Yasuhiro Inoue ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Black Rot ◽  
Xanthomonas Campestris Pv Campestris

scholarly journals Antagonism of yeasts to Xanthomonas campestris pv. campestris on cabbage phylloplane in field

1999 ◽  
Vol 30 (3) ◽  
pp. 191-195 ◽  
Author(s):  
Sayonara M.P. Assis ◽  
Rosa L.R. Mariano ◽  
Sami J. Michereff ◽  
Gil Silva ◽  
Elizabeth A.A. Maranhão
Keyword(s):  
Disease Severity ◽  
Xanthomonas Campestris ◽  
Antagonistic Activity ◽  
Black Rot ◽  
Significant Difference ◽  
Xanthomonas Campestris Pv Campestris

Twenty yeast isolates, obtained from cabbage phylloplane, were evaluated for antagonistic activity against Xanthomonas campestris pv. campestris, in field. Plants of cabbage cv. Midori were pulverized simultaneously with suspensions of antagonists and pathogen. After 10 days, plants were evaluated through percentage of foliar area with lesions. Percentage of disease severity reduction (DSR%) was also calculated. Yeast isolates LR32, LR42 and LR19 showed, respectively, 72, 75 and 79% of DSR. These antagonists were tested in seven different application periods in relation to pathogen inoculation (T1=4 d before; T2=simultaneously; T3=4 d after; T4=4 d before + simultaneously; T5=4 d after + simultaneously; T6=4 d before + 4 d after; T7=4 d before + simultaneously + 4 d after). The highest DSRs were showed by LR42 (71%), LR42 (67%), LR35 (69%) and LR19 (68%) in the treatments T7, T4, T5 and T6, which significantly differed from the others. The same yeast antagonists were also tested for black rot control using different cabbage cultivars (Fuyutoyo, Master-325, Matsukaze, Midori, Sekai I and Red Winner). The DSRs varied from 58 to 61%, and there was no significant difference among cultivars.

scholarly journals Characterization of Xanthomonas campestris pv. campestris in Algeria

2021 ◽  
Vol 60 (1) ◽  
pp. 51-62
Author(s):  
Samia LAALA ◽  
Sophie CESBRON ◽  
Mohamed KERKOUD ◽  
Franco VALENTINI ◽  
Zouaoui BOUZNAD ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Housekeeping Genes ◽  
First Record ◽  
Black Rot ◽  
Physiological And Biochemical Characteristics ◽  
Main Production ◽  
Production Areas ◽  
Cruciferous Plants ◽  
Xanthomonas Campestris Pv Campestris

Xanthomonas campestris pv. campestris (Xcc) causes the black rot of cruciferous plants. This seed-borne bacterium is considered as the most destructive disease to cruciferous crops. Although sources of contamination are various, seeds are the main source of transmission. Typical symptoms of black rot were first observed in 2011 on cabbage and cauliflower fields in the main production areas of Algeria. Leaf samples displaying typical symptoms were collected during 2011 to 2014, and 170 strains were isolated from 45 commercial fields. Xcc isolates were very homogeneous in morphological, physiological and biochemical characteristics similar to reference strains, and gave positive pathogenicity and molecular test results (multiplex PCR with specific primers). This is the first record of Xcc in Algeria. Genetic diversity within the isolates was assessed in comparison with strains isolated elsewhere. A multilocus sequence analysis based on two housekeeping genes (gyrB and rpoD) was carried out on 77 strains representative isolates. The isolates grouped into 20 haplotypes defined with 68 polymorphic sites. The phylogenetic tree obtained showed that Xcc is in two groups, and all Algerian strains clustered in group 1 in three subgroups. No relationships were detected between haplotypes and the origins of the seed lots, the varieties of host cabbage, the years of isolation and agroclimatic regions.

scholarly journals Occurrence of Bacterial Stem Rot, Caused by Erwinia chrysanthemi, on Field-Grown Tomato in Florida

Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 831-831 ◽  
Author(s):  
D. O. Chellemi ◽  
H. A. Dankers ◽  
K. Hill ◽  
R. E. Cullen ◽  
G. W. Simone ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Methyl Esters ◽  
Sole Source ◽  
Erwinia Chrysanthemi ◽  
Identification System ◽  
Bacterial Cells ◽  
Sterile Water ◽  
Microbial Identification ◽  
Pure Cultures ◽  
Tomato Isolate

In September 1997, wilted 4-week-old tomato (Lycopersicon esculentum Mill.) plants were observed in a commercial production field in St. Lucie County, FL. Closer inspection of affected plants revealed hollow stems and petioles with dark, water-soaked lesions. Diseased tissue was macerated and streaked onto nutrient agar (NA) and crystal violet pectate (CVP) agar. After incubation for 2 days at 30°C, isolates produced pits on the CVP agar. Isolates were transferred onto NA and the incubation and transfer procedure was performed two additional times to obtain pure cultures. Suspensions of bacterial cells were injected into tomato and tobacco leaves to test for a hypersensitive or pathogenic reaction. Isolates produced collapsed necrotic tissue on tomato while no reaction was observed on tobacco. Tests for differentiating species and subspecies in the ‘carotovora’ group of Erwinia were conducted following the protocol of Dickey and Kelman (1). With known cultures of E. carotovora subsp. carotovora and E. chrysanthemi as controls, the isolate from tomato was determined to function as a facultative anaerobe, utilize asparagine as a sole source of carbon and nitrogen, and give positive reactions for pectate degradation, phosphatase, and growth at 37°C. Known cultures of E. carotovora subsp. carotovora, E. chrysanthemi, and the tomato isolate were grown on trypticase soy broth agar for 24 h at 28°C and their cellular fatty acids derivatized to fatty acid methyl esters (FAMEs). Statistical analyses of FAME profile data (MIDI Microbial Identification System, Newark, DE, version 3.60) identified the tomato isolate as Erwinia chrysanthemi. Pathogenicity was determined by inoculating 50-day-old tomato plants (cv. SunPride) with a suspension of E. chrysanthemi obtained from nutrient broth plates incubated at 24°C for 60 h. Three plants each were inoculated with the E. chrysanthemi identified from tomato, sterile water, and known cultures of E. chrysanthemi and E. carotovora subsp. carotovora by placing a drop at the junction of the petiole and stem and passing a sterile needle through the drop into the stem. Plants were maintained in a greenhouse. Dark, water-soaked cankers were observed on the stems of plants inoculated with E. chrysanthemi, including the tomato isolate and E. carotovora subsp. carotovora, after 7 days. No symptoms were observed on plants inoculated with sterile water. Reisolation of the pathogen and identification was performed with tissue from one of the symptomatic inoculated plants. Analyses of FAMEs confirmed E. chrysanthemi as the causal agent. This is the first report of E. chrysanthemi causing a vascular disease of field-grown tomato in Florida. Reference: (1) R. S. Dickey and A. Kelman. 1988. Pages 44–59 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. N. W. Schaad, ed. American Phytopathological Society, St. Paul, MN.

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