Threat Perception of Bacterial Plant Pathogen Xanthomonas campestris pv. campestris (Pammel) Dowson, Causing Black Rot Disease in Cabbage fields

2020 ◽  
Vol 5 (2) ◽  
pp. 174-186
Author(s):  
S G. Borkar
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.


Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 804
Author(s):  
Miroslav Baránek ◽  
Viera Kováčová ◽  
Filip Gazdík ◽  
Milan Špetík ◽  
Aleš Eichmeier ◽  
...  

Epigenetics is the study of heritable alterations in phenotypes that are not caused by changes in DNA sequence. In the present study, we characterized the genetic and phenotypic alterations of the bacterial plant pathogen Xanthomonas campestris pv. campestris (Xcc) under different treatments with several epigenetic modulating chemicals. The use of DNA demethylating chemicals unambiguously caused a durable decrease in Xcc bacterial virulence, even after its reisolation from infected plants. The first-time use of chemicals to modify the activity of sirtuins also showed some noticeable results in terms of increasing bacterial virulence, but this effect was not typically stable. Changes in treated strains were also confirmed by using methylation sensitive amplification (MSAP), but with respect to registered SNPs induction, it was necessary to consider their contribution to the observed polymorphism. The molecular basis of the altered virulence was deciphered by using dualRNA-seq analysis of treated Xcc strains infecting Brassica rapa plants. The results of the present study should promote more intensive research in the generally understudied field of bacterial epigenetics, where artificially induced modification by epigenetic modulating chemicals can significantly increase the diversity of bacterial properties and potentially contribute to the further development of the fields, such as bacterial ecology and adaptation.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2705
Author(s):  
Lu Lu ◽  
Sokrat G. Monakhos ◽  
Yong Pyo Lim ◽  
So Young Yi

Black rot disease, caused by Xanthomonas campestris pv. campestris (Xcc), results in significant yield losses in Brassica oleracea crops worldwide. To find black rot disease-resistant cabbage lines, we carried out pathogenicity assays using the scissor-clipping method in 94 different B. oleracea lines. By comparing the lesion areas, we selected a relatively resistant line, Black rot Resistance 155 (BR155), and a highly susceptible line, SC31. We compared the two cabbage lines for the Xcc-induced expression pattern of 13 defense-related genes. Among them, the Xcc-induced expression level of PR1 and antioxidant-related genes (SOD, POD, APX, Trx H, and CHI) were more than two times higher in BR155 than SC31. Nitroblue tetrazolium (NBT) and diaminobenzidine tetrahydrochloride (DAB) staining analysis showed that BR155 accumulated less Xcc-induced reactive oxygen species (ROS) than did SC31. In addition, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays showed that BR155 had higher antioxidant activity than SC31. This study, focused on the defense responses of cabbage during the early biotrophic stage of infection, indicated that Xcc-induced ROS might play a role in black rot disease development. We suggest that non-enzymatic antioxidants are important, particularly in the early defense mechanisms of cabbage against Xcc.


2015 ◽  
Vol 7 (2) ◽  
pp. 780-785
Author(s):  
Atit Maji ◽  
Ranjan Nath

Cabbage, is one of the most important crops of the cole group of vegetables. In India it ranks next to cauliflower in acreage and first in production among cole crops occupying an area of 3,72,000 ha with annual production of 8534,000 tons. It covers about 4.3% area under vegetable crops in India. In West Bengal cabbage covers 78200.00 ha of area and the total production is 2197400.00 MT. Black rot is a major disease of cabbage (Brassica oleracea var. capitata), caused by Xanthomonas campestris pv. campestris (Xcc) . The disease has been observed in all cabbage growing areas of Bolpur, Birbhum, West Bengal. The present study was carried out on the pathology of black rot disease of cabbage. Morphological, cultural, biochemical, and physiological characteristics of the pathogen were studied. The bacterium produced small, yellow, circular, entire, smooth and shining colonies in the culture medium. The optimum temperature for the growth was found 300C and white light supported maximum growth of the bacterium. Nutritional studies revealed that sucrose gave maximum growth followed by maltase, lactose, dextrose and fructose as the carbon source in the nutrient broth. Black rot of cabbage pathogen also infected other crops of crucifereae family such as Cauliflower, Knol khol, Mustard, Radish and Rape seed. These findings regarding the pathogen may help to formulate the more appropriate way and judicious application of different management options against the diease in this zone.


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