Xanthomonas campestris pv. campestris (black rot).

Author(s):  
Carmen Nieves Mortensen

Abstract Black rot is considered the most important worldwide disease of crucifers. The disease is known to exist in the cool coastal climates of northern Europe and North America but was seldom a problem there until the 1990s. Its potential for crop damage is also considered low in New Zealand, and parts of Australia. In many regions of Central and Eastern Europe, Central Asia (Kazakhstan), China, tropical and subtropical regions of Asia, Africa and South America where brassicas are common and cultivated without crop rotation, black rot is always present. Seed production in those regions is commonly associated with high levels of seedborne Xcc (Williams, 1980). Even minor, visually undetectable development of black rot may considerably increase damage to plants by soft rot caused by Erwinia carotovora, Pseudomonas spp. and other opportunistic pathogens (Djalilov et al., 1989).

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

2010 ◽  
Vol 14 ◽  
pp. 139-146
Author(s):  
Van De Jong ◽  
B.E. Braithwaite ◽  
T.L. Roush ◽  
A. Stewart ◽  
J.G. Hampton

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


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

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.


2021 ◽  
Vol 60 (1) ◽  
pp. 51-62
Author(s):  
Samia LAALA ◽  
Sophie CESBRON ◽  
Mohamed KERKOUD ◽  
Franco VALENTINI ◽  
Zouaoui BOUZNAD ◽  
...  

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.


1999 ◽  
Vol 62 (4) ◽  
pp. 343-348 ◽  
Author(s):  
CHING-HSING LIAO ◽  
GERALD M. SAPERS

Growth of Listeria monocytogenes on potato tuber slices and its interaction with four representative species of soft rot bacteria (Pseudomonas fluorescens, P. viridiflava, Erwinia carotovora subsp. carotovora, and Xanthomonas campestris) were investigated. When potato tuber slices were inoculated with one of two L. monocytogenes strains (Scott A and ATCC 15313), an increase in numbers of 3 to 4 logs per gram of tissue was observed with samples that were stored at 20°C for 6 days. However, an increase of about 2 logs was observed with samples that were stored at 8°C for 12 days. When potato slices were simultaneously inoculated with L. monocytogenes and one of the four soft rot bacteria, the growth of L. monocytogenes was inhibited in the presence of P. fluorescens or P. viridiflava but was not significantly affected in the presence of E. carotovora or X. campestris. The antagonism of the two pseudomonads to L. monocytogenes was also observed in potato tuber extract and in culture media. Formation of inhibition zones was observed only in iron-deficient media but not in the medium supplemented with FeCl3. In addition, production of fluorescent siderophore (pyoverdin) by these two pseudomonads was demonstrated. L. monocytogenes was unable to colonize macerated plant tissue induced by soft-rotting bacteria 2 days before inoculation of the pathogen. These results indicate that growth of L. monocytogenes on potato tuber slices is differentially affected by soft rot bacteria and that antagonism of fluorescent pseudomonads to L. monocytogenes is possibly caused by the production of iron-chelating siderophore by these pseudomonads.


2000 ◽  
Vol 78 (9) ◽  
pp. 1144-1149 ◽  
Author(s):  
P A Gay ◽  
S Tuzun

The physiological mechanisms associated with resistance of cabbage to black rot disease seem to be associated with the hydathodes. To investigate the role of hydathodes in disease resistance, total peroxidase activities, anionic peroxidase isozyme expression, and lignin deposition were determined in hydathodes of resistant (Hancock and Green Cup), partially resistant (Cheers), and susceptible (Strukton and Perfect Ball) cabbage varieties (Brassica oleracea L.) during pathogenesis with Xanthomonas campestris pv. campestris. Four-week-old plants were petiole-inoculated with a highly virulent strain of X. campestris pv. campestris (FD91L). Hydathodal fluids were collected daily over a 14-day period from infected plants as well as noninfected, mock-inoculated control plants. Hydathodal fluids of resistant varieties had greater peroxidase activity when compared to susceptible ones, with infected plants having higher peroxidase levels than noninfected plants. Isoelectric focusing revealed the presence of four anionic peroxidase isozymes in hydathodal fluids, with the most anionic one (pI of 3.6) accumulating only upon infection. Lignin deposition in and around the hydathodes was associated with the accumulation of this particular isozyme in hydathodal fluids. The evidence suggests that a rapid, systemic response is associated with resistance to the bacterial pathogen.Key words: peroxidases, hydathodes, isozymes, black rot disease, cabbage, Xanthomonas campestris pv. campestris.


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