Relation of xylem plugging to black rot lesion development in cabbage

1970 ◽  
Vol 48 (2) ◽  
pp. 391-401 ◽  
Author(s):  
John C. Sutton ◽  
Paul H. Williams
Keyword(s):  
Xanthomonas Campestris ◽  
Water Shortage ◽  
Black Rot ◽  
Electrolyte Balance ◽  
Lesion Development ◽  
Virulent Isolate ◽  
Viable Bacteria ◽  
Weakly Virulent ◽  
Plug Formation ◽  
The Relationship

Black rot lesion development in cabbage leaves was correlated with accumulation of plugging material in the xylem vessels as Xanthomonas campestris multiplied and spread. Plug formation preceded a partial disorganization of the xylem, and spillage of bacteria from the vessels. The movement of eosin and 32PO43− was blocked within the vessels, and plugs caused water shortage in affected cells. Vein blackening, the first symptom of the disease, occurred after plugs had formed, and was associated with an accumulation of melanins among collapsing cells of the vascular bundle. The population of viable bacteria within the veins declined rapidly as the veins blackened.Advance of the bacteria in the xylem vessels accounted for the relationship between venation and lesion spread. A weakly virulent isolate spread extensively in the xylem vessels if inoculated with a virulent isolate, but not when inoculated alone. Acid mucopolysaccharide plugging material was not formed in vessels infected with the weakly virulent isolate.Water stress in cells of interveinal tissues of inoculated leaves resulted in chlorosis, loss in turgor, and loss of electrolytes. If net water loss from infected leaves was prevented by high atmospheric relative humidity, affected cells remained green and turgid and maintained their electrolyte balance.

Comparison of extracellular polysaccharide of Xanthomonas campestris from culture and from infected cabbage leaves

1970 ◽  
Vol 48 (3) ◽  
pp. 645-651 ◽  
Author(s):  
John C. Sutton ◽  
Paul H. Williams
Keyword(s):  
Xanthomonas Campestris ◽  
Extracellular Polysaccharide ◽  
Hexadecyltrimethylammonium Bromide ◽  
Gas Liquid Chromatography ◽  
Aqueous Extracts ◽  
Polysaccharide Fraction ◽  
Virulent Isolate ◽  
Culture Filtrates ◽  
Weakly Virulent ◽  
Repeated Precipitation

The extracellular polysaccharide fraction of Xanthomonas campestris was precipitated with hexadecyltrimethylammonium bromide from aqueous extracts of cabbage leaves infected with the black rot pathogen, and further purified by repeated precipitation with ethanol. The polysaccharide fraction was shown to be similar to extracellular polysaccharide fraction purified from culture fitlrates of X. campestris. Sugars present in samples of acid-hydrolyzed polysaccharide were identified by gas–liquid chromatography. Chromatograms showed that polysaccharide purified from infected cabbage leaves contained glucose, mannose, and glucuronolactone in ratios similar to those of the polysaccharide from culture filtrates. Polysaccharide purified from noninfected cabbage leaves contained only glucose and galactose. The polysaccharide from infected cabbage leaves was serologically related to polysaccharide from culture filtrates. In immunodiffusion tests both the polysaccharide fractions from culture filtrates and that from infected leaves reacted to give two precipitin bands with an antiserum to the polysaccharide from culture filtrates. No precipitin bands formed with polysaccharide from noninfected leaves. Antibodies against the culture polysaccharide were completely removed from the antiserum by the polysaccharides isolated from infected cabbage leaves. A weakly virulent isolate of X. campestris did not produce extracellular polysaccharide in culture filtrates.

scholarly journals Genomic insights advance the fight against black rot of crucifers

2021 ◽  
Vol 87 (3) ◽  
pp. 127-136
Author(s):  
Zoë E. Dubrow ◽  
Adam J. Bogdanove
Keyword(s):  
Virulence Factors ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Impact Resistance ◽  
Resistance Breeding ◽  
Genetic Data ◽  
Black Rot ◽  
Inoculum Sources ◽  
New Knowledge ◽  
The World

AbstractXanthomonas campestris pv. campestris, the causal agent of black rot of crucifers, was one of the first bacterial plant pathogens ever identified. Over 130 years later, black rot remains a threat to cabbage, cauliflower, and other Brassica crops around the world. Recent genomic and genetic data are informing our understanding of X. campestris taxonomy, dissemination, inoculum sources, and virulence factors. This new knowledge promises to positively impact resistance breeding of Brassica varieties and management of inoculum sources.

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

Opportunities for developing value-added brassica seed

2010 ◽  
Vol 14 ◽  
pp. 139-146
Author(s):  
Van De Jong ◽  
B.E. Braithwaite ◽  
T.L. Roush ◽  
A. Stewart ◽  
J.G. Hampton
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
Xanthomonas Campestris ◽  
Cultural Practices ◽  
Effective Means ◽  
Value Added ◽  
Primary Source ◽  
Common Disease ◽  
Black Rot ◽  
Crop Losses

New Zealand produces approximately 5,500 tonnes of brassica seed per year, two thirds of which, valued at $13M, is exported. Black rot caused by Xanthomonas campestris pv. campestris is a common disease of brassicas, and while crop losses are not extensive in New Zealand, internationally total crop losses have been reported. Seeds are the primary source of inoculum and the ease with which this inoculum spreads means that even small traces can cause severe epidemics. Genetic resistance to black rot is a complex trait which makes breeding for resistance in brassicas challenging. The effectiveness of chemical and cultural practices is variable. Biological control with natural antagonistic microbes may provide a more effective means of controlling black rot and other pests and diseases, and create opportunities for increasing the export value of brassica seed. Current cultural practices and the potential for biological control for the management of black rot are reviewed. Keywords: biocontrol, Brassicaceae, crucifer

scholarly journals Quantification of Airborne Inoculum as an Aid in the Management of Leaf Blight of Onion Caused by Botrytis squamosa

Plant Disease ◽  
2005 ◽  
Vol 89 (7) ◽  
pp. 726-733 ◽  
Author(s):  
O. Carisse ◽  
H. A. McCartney ◽  
J. A. Gagnon ◽  
L. Brodeur
Keyword(s):  
Leaf Growth ◽  
Control Plot ◽  
Leaf Blight ◽  
Yield Reduction ◽  
Lesion Development ◽  
Botrytis Squamosa ◽  
Airborne Inoculum ◽  
Significant Yield ◽  
Epidemic Development ◽  
The Relationship

Botrytis leaf blight, caused by Botrytis squamosa, is a common and frequently damaging disease of onion crops, but the severity of epidemics varies widely from year to year. The disease is initiated and spread by airborne conidia. The relationship between airborne conidium concentration (ACC) and lesion development was studied in the field. A linear relationship was found between ACC and number of lesions per leaf: ACC values of 10 to 15 and 25 to 35 conidia m-3 were associated with 1 and 2.5 lesions per leaf, respectively. In 2000 and 2001, at three sites, four different criteria were used to start a fungicide spray program and their effect on epidemic development was compared with that of a grower's conventional schedule. The criteria were: at the fourth-true-leaf growth stage; according to an inoculum production index; when the ACC reached 10 to 15 conidia m-3; and when the ACC reached 25 to 35 conidia m-3. A nonsprayed control plot was included in the trial. Fungicide programs started when the ACC reached 10 to 15 conidia m-3 were as effective as the conventional program, but used fewer sprays. A fungicide spray program based on measurements of ACC and disease severity was evaluated in 2002 and 2003 in five and three commercial onion fields, respectively. At each site, half of the field was sprayed according to the grower's schedule and, in the other half, fungicide sprays were initiated when a threshold of 10 to 15 conidia m-3 or five lesions on the lower leaf (whichever came first) was reached. Overall, the number of fungicide applications was reduced by 75 and 56% in 2002 and 2003, respectively, without causing significant yield reduction. In both years, the reduction in number of fungicide applications was due mainly to the delay in initiation of the fungicide program.

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 Identification of Black Rot Resistance in a Wild Brassica Species and Its Potential Transferability to Cauliflower

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1400
Author(s):  
Xiao-Guang Sheng ◽  
Ferdinando Branca ◽  
Zhen-Qing Zhao ◽  
Jian-Sheng Wang ◽  
Hui-Fang Yu ◽  
...  
Keyword(s):  
Xanthomonas Campestris ◽  
Resistance Breeding ◽  
Brassica Species ◽  
Gene Location ◽  
F1 Hybrids ◽  
Black Rot ◽  
Resistant Parent ◽  
F2 Population ◽  
Related Wild Species ◽  
Wild Accessions

Black rot is a destructive disease that affects B. oleracea crops, causing significant losses to growers throughout the world. The purpose of this study was to screen out new sources resistant to Xanthomonas campestris pv. campestris race 4 (Xcc4) in 26 cauliflower and six related wild species, and to assess the inheritance of resistance. The results indicate that most of the tested accessions were susceptible or had intermediate resistance, except the Boc4601 (a cauliflower stable inbred line) and PI435896, UNICT5168, and UNICT5169 (wild accessions). Among them, UNICT5169 (Brassica montana) and PI435896 (Brassica balearica) showed the strongest resistance to Xcc4, with significantly lower disease index (DI), area of the infected part (AIP) and proportion of the infected part to the total leaf area (PTL) values. UNICT 5169 was selected as an Xcc4-resistant parent because of its relatively good cross seed-setting rate with cauliflower cultivars. F1 hybrids were successfully produced between this wild resistant accession (UNICT 5169) and one susceptible cauliflower breeding line (Boc3202-4), indicating the potential transferability of this resistance to cauliflower. The results of the symptoms severity evaluation of the F2 population indicate that Xcc4 resistance in UNICT5169 is a quantitative trait, which guides future resistance gene location and black rot resistance breeding.

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.

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