scholarly journals Pathogenicity and Relative Abundance of Dickeya and Pectobacterium Species in Switzerland: An Epidemiological Dichotomy

2021 ◽  
Vol 9 (11) ◽  
pp. 2270
Author(s):  
Patrice de Werra ◽  
Christophe Debonneville ◽  
Isabelle Kellenberger ◽  
Brice Dupuis

Pectobacterium and Dickeya species are the causal agents of blackleg and soft rot diseases in potatoes. The main pathogenic species identified so far on potatoes are Dickeya dianthicola, Dickeya solani, Pectobacterium atrosepticum, Pectobacterium brasiliense, Pectobacterium carotovorum, and Pectobacterium parmentieri. Ten years ago, the most prevalent Soft Rot Pectobacteriaceae in Europe were the Dickeya species, P. atrosepticum and P. carotovorum, with some variations among countries. Since then, a drastic increase in the abundance of P. brasiliense has been observed in most European countries. This shift is difficult to explain without comparing the pathogenicity of all Dickeya and Pectobacterium species. The pathogenicity of all the above-mentioned bacterial species was assessed in field trials and in vitro tuber slice trials in Switzerland. Two isolates of each species were inoculated by soaking tubers of cv. Desiree in a suspension of 105 CFU/mL, before planting in the field. For all trials, the Dickeya species were the most virulent ones, but long-term strain surveys performed in Switzerland indicate that P. brasiliense is currently the most frequent species detected. Our results show that the pathogenicity of the species is not the main factor explaining the high prevalence of P. brasiliense and P. parmentieri in the Swiss potato fields.

Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 482 ◽  
Author(s):  
Nader A. Ashmawy ◽  
Said I. Behiry ◽  
Asma A. Al-Huqail ◽  
Hayssam M. Ali ◽  
Mohamed Z. M. Salem

Phenolic acids and natural extracts, as ecofriendly environmental agents, can be used as bio bactericides against the growth of plant pathogenic bacteria. In this study, isolation trails from infected potato tubers and stems that showed soft rot symptoms in fields revealed two soft rot bacterial isolates and were initially identified through morphological, physiological, and pathogenicity tests. The molecular characterization of these isolates via PCR, based on the 16S rRNA region, was carried out by an analysis of the DNA sequence via BLAST and Genbank, and showed that the soft rot bacterial isolates belong to Pectobacterium carotovorum subsp. carotovorum (PCC1) and Dickeya solani (Ds1). The in vitro results of the tested phenolic acids against the cultured bacterial isolates proved that concentrations of 800, 1600, and 3200 μg/mL were the most effective. Ferulic acid was the potent suppressive phenolic acid tested against the Ds1 isolate, with an inhibition zone ranging from 6.00 to 25.75 mm at different concentrations (25–3200 μg/mL), but had no effect until reaching a concentration of 100 μg/mL in the PCC1 isolate, followed by tannic acid, which ranged from 7.00 to 25.50 mm. On the other hand, tannic acid resulted in a significant decrease in the growth rate of the PCC1 isolate with a mean of 9.11 mm. Chlorogenic acid was not as effective as the rest of the phenolic acids compared with the control. The n-hexane oily extract (HeOE) from Bougainvillea spectabilis bark showed the highest activity against PCC1 and Ds1, with inhibition zone values of 12 and 12.33 mm, respectively, at a concentration of 4000 μg/mL; while the HeOE from Citharexylum spinosum wood showed less activity. In the GC/MS analysis, nonanal, an oily liquid compound, was found ata percentage of 38.28%, followed by cis-2-nonenal (9.75%), which are the main compounds in B. spectabilis bark HeOE, and 2-undecenal (22.39%), trans-2-decenal (18.74%), and oleic acid (10.85%) were found, which are the main compounds in C. spinosum wood HeOE. In conclusion, the phenolic acids and plant HeOEs seem to raise the resistance of potato plants, improving their defense mechanisms against soft rot bacterial pathogens.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
M’hamed BENADA ◽  
Boualem BOUMAAZA ◽  
Sofiane BOUDALIA ◽  
Omar KHALADI

Abstract Background The development of ecofriendly tools against plant diseases is an important issue in crop protection. Screening and selection process of bacterial strains antagonists of 2 pathogenic bacterial species that limit very important crops, Erwinia amylovora, the causal agent of the fire blight disease, and Pectobacterium carotovorum, the causal agent of bacterial potato soft rot, were reported. Bacterial colonies were isolated from different ecological niches, where both pathogens were found: rhizosphere of potato tubers and fruits and leaves of pear trees from the northwest region of Algeria. Direct and indirect confrontation tests against strains of E. amylovora and P. carotovorum were performed. Results Results showed a significant antagonistic activity against both phytopathogenic species, using direct confrontation method and supernatants of cultures (p<0.005). In vitro assays showed growth inhibitions of both phytopathogenic species. Furthermore, results revealed that the strains of S. plymuthica had a better inhibitory effect than the strains of P. fluorescens against both pathogens. In vivo results on immature pear fruits showed a significant decrease in the progression of the fire blight symptoms, with a variation in the infection index from one antagonistic strain to another between 31.3 and 50%, and slice of potato showed total inhibition of the pathogen (P. carotovorum) by the antagonistic strains of Serratia plymuthica (p<0.005). Conclusion This study highlighted that the effective bacteria did not show any infection signs towards plant tissue, and considered as a potential strategy to limit the fire blight and soft rot diseases.


2017 ◽  
Vol 52 (2) ◽  
pp. 135-140 ◽  
Author(s):  
MM Rahman ◽  
AA Khan ◽  
IH Mian ◽  
AM Akanda ◽  
MZ Alam

Bactericidal effect was investigated by chemicals against potato soft rot bacteria in vitro and in storage. The chemicals were acetic acid, boric acid, bleaching powder, lactic acid, calcium hydroxide, calcium chloride, potassium chloride and sodium hypo-chloride. Among eight  chemicals only three chemicals viz. acetic acid, boric acid and bleaching powder showed bactericidal activity against potato soft rot bacteria  Pectobacterium carotovorum subsp. carotovorum (E. carotovora subsp. carotovora) P-138 in vitro. Based on the results of in vitro experiment three chemicals, acetic acid, boric acid and bleaching powder were used to control soft rot disease of potato in storage. Fresh potato tubers were dipped in 0.2% solution/suspensions of acetic acid, boric acid and bleaching powder for 30 min. Then soft rot bacteria Pectobacterium carotovorum subsp. carotovorum P-138 was inoculated on potato. Finally potatoes were stored for 22 weeks in net bags in sterilized condition. All the three chemicals significantly decreased the infection rate, loss in weight and increased percentage of disease reduction (PDR) of potato. Boric acid was the most effective in controlling the soft rot disease of potato in storage followed by acetic acid and bleaching powder. So these chemicals may be used for seed purpose storage of potato tubers for year round storage at farmer’s level.Bangladesh J. Sci. Ind. Res. 52(2), 135-140, 2017


2012 ◽  
Vol 63 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Tadeusz Kowalski ◽  
Czesław Bartnik

The present paper presents the results of long-term observations of differences in growth and morphology of colonies of <i>C. fraxinea</i> isolated from ash stems with symptoms of dieback and the results of studies on effects of temperature on growth and morphology of colonies <i>in vitro</i>. Thirty randomly chosen <i>C. fraxinea</i> cultures, originating from six Forest Districts in southern and northern Poland, viz. Andrychów, Gryfice, Kańczuga, Lębork, Miechów and Mircze, were included in the temperature assay. Colony growth and morphology were evaluated <i>in vitro</i>, on malt extract agar. Two replicates of each isolate were incubated at 5, 10, 15, 20, 25 and 30°C in darkness. Colonies of <i>C. fraxinea</i> isolated from necrotic stem tissues of diseased ash trees differed greatly in colour, structure, growth rate, presence of sectors and stromata as well as the intensity of conidial sporulation. Colony characters were often lost in further sub-cultures grown on the same medium. Colonies of <i>C. fraxinea</i> grew at 5-25°C <i>in vitro</i>. Three isolates still grew, though slowly, at 30°C. The optimum temperature for growth was 20°C. Among 30 isolates tested, five grew most quickly at 25°C and four at 15°C. Differences among colony diameters recorded at 5, 10, 15, 20 and 30°C were statistically significant, while differences at 15 and 25°C were not. At some temperatures, statistically significant differences in growth rate were related to the origin of the isolates. There were three main colony colour types. Temperature was the main factor affecting colony morphology <i>in vitro</i>. The formation of sectors was observed in 36% of colonies, pseudoparenchymatous stromata in 10.4% of colonies, and white crystalline substances in 53.3% of colonies. The results of <i>in vitro</i> observations were used for discussion of the effects of temperature on growth and activity of <i>C. fraxinea</i> <i>in vivo</i>.


2020 ◽  
Author(s):  
Renata Lebecka ◽  
Iwona Wasilewicz-Flis ◽  
Dariusz Mańkowski

AbstractPotato growers suffer losses due to potato soft rot and blackleg caused by pectinolytic bacteria of different species. These bacteria cause yield loss during cultivation and storage, and can be transmitted to the next generations through seed tubers. The prevalence of Pectobacterium atrosepticum has decreased over the last 20 years in Europe in favour of Dickeya solani and P. carotovorum subsp. brasiliense. Twenty-six diploid interspecific Solanum hybrids, previously selected for tuber resistance to P. atrosepticum, were screened for resistance to a highly aggressive D. solani strain in terms of tuber and blackleg reaction. The bacterial strain used for inoculation was characterised by a relatively high optimal growth temperature in vitro, ranging from 33 to 35 °C. Twenty-four diploid clones did not differ in terms of tuber reaction to inoculation with this strain of bacteria in comparison with the clone USA 249, which is the somatic hybrid of S. brevidens (+) S. tuberosum with proven resistance to Pectobacterium. Seventeen clones performed significantly better in terms of blackleg resistance than the resistant potato cultivar Glada. Eleven of the selected diploids produced unreduced gametes, which allows their use in improving the resistance of tetraploid potatoes to diseases caused by bacteria of both Pectobacterium and Dickeya.


1996 ◽  
Vol 135 (1) ◽  
pp. 269-278 ◽  
Author(s):  
F Guinet ◽  
J A Dvorak ◽  
H Fujioka ◽  
D B Keister ◽  
O Muratova ◽  
...  

Asexually replicating populations of Plasmodium parasites, including those from cloned lines, generate both male and female gametes to complete the malaria life cycle through the mosquito. The generation of these sexual forms begins with the induction of gametocytes from haploid asexual stage parasites in the blood of the vertebrate host. The molecular processes that govern the differentiation and development of the sexual forms are largely unknown. Here we describe a defect that affects the development of competent male gametocytes from a mutant clone of P. falciparum (Dd2). Comparison of the Dd2 clone to the predecessor clone from which it was derived (W2'82) shows that the defect is a mutation that arose during the long-term cultivation of asexual stages in vitro. Light and electron microscopic images, and indirect immunofluorescence assays with male-specific anti-alpha-tubulin II antibodies, indicate a global disruption of male development at the gametocyte level with at least a 70-90% reduction in the proportion of mature male gametocytes by the Dd2 clone relative to W2'82. A high prevalence of abnormal gametocyte forms, frequently containing multiple and unusually large vacuoles, is associated with the defect. The reduced production of mature male gametocytes may reflect a problem in processes that commit a gametocyte to male development or a progressive attrition of viable male gametocytes during maturation. The defect is genetically linked to an almost complete absence of male gamete production and of infectivity to mosquitoes. This is the first sex-specific developmental mutation identified and characterized in Plasmodium.


2016 ◽  
Vol 57 (1) ◽  
pp. 1-8
Author(s):  
Sima Azadmanesh ◽  
Javad Mozafari ◽  
Nader Hasanzadeh ◽  
Cobra Moslemkhani

Abstract In vitro screening techniques were used to evaluate 46 genotypes of Iranian potato collection for resistance to bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum (Pcc). One month old in vitro rooted potato plantlets were inoculated by two inoculation techniques under in vitro conditions: 1) sterile toothpicks dipped into bacterial suspension and pressed into the crown of plantlets and 2) the freshly cut crown of plantlets were dipped into bacterial suspension of 108 cfu ∙ ml-1 for 10 min. Typical soft rot disease symptoms, including the percentage of wilted leaves were recorded on inoculated plantlets 3, 6, 9, 12 and 15 days post-inoculation. The potato genotypes which were examined responded differently to Pcc and varying levels of resistance were observed. Potato genotype AG showed the highest level of resistance. Results obtained from in vitro screening were then verified by classical tuber slice assay. The verifications were conducted using five representative cultivars: Milva, Ramus, Picaso, Marfona and Agria which responded similarly to both in vitro and classical evaluation systems. Similar results obtained from these tests indicated that the in vitro screening technique developed in this study could provide a simple and rapid whole plant assay in selecting resistant potato genotypes against bacterial soft rot.


2010 ◽  
Vol 76 (22) ◽  
pp. 7541-7549 ◽  
Author(s):  
Eunjung Roh ◽  
Tae-Ho Park ◽  
Myung-il Kim ◽  
Seungdon Lee ◽  
Sangryeol Ryu ◽  
...  

ABSTRACT Two different bacteriocins, carotovoricin and carocin S1, had been found in Pectobacterium carotovorum subsp. carotovorum, which causes soft-rot disease in diverse plants. Previously, we reported that the particular strain Pcc21, producing only one high-molecular-weight bacteriocin, carried a new antibacterial activity against the indicator strain Pcc3. Here, we report that this new antibacterial activity is due to a new bacteriocin produced by strain Pcc21 and named carocin D. Carocin D is encoded by the caroDK gene located in the genomic DNA together with the caroDI gene, which seems to encode an immunity protein. N-terminal amino acid sequences of purified carocin D were determined by Edman degradation. In comparison with the primary translation product of caroDK, it was found that 8 amino acids are missing at the N terminus. This finding proved that carocin D is synthesized as a precursor peptide and that 8 amino acids are removed from its N terminus during maturation. Carocin D has two putative translocation domains; the N-terminal and C-terminal domains are homologous to those of Escherichia coli colicin E3 and Pseudomonas aeruginosa S-type pyocin, respectively. When caroDK and caroDI genes were transformed into carocin D-sensitive bacteria such as Pcc3, the bacteria became resistant to this bacteriocin. Carocin D has one putative DNase domain at the extreme C terminus and showed DNase activity in vitro. This bacteriocin had slight tolerance to heat but not to proteases. The caroDK gene was present in only 5 of 54 strains of P. carotovorum subsp. carotovorum. These results indicate that carocin D is a third bacteriocin found in P. carotovorum subsp. carotovorum, and this bacteriocin can be readily expressed in carocin D-sensitive nonpathogenic bacteria, which may have high potential as a biological control agent in the field.


2016 ◽  
Vol 5 (2) ◽  
pp. 61-66
Author(s):  
Stephen Kironji Githeng'u ◽  
Samuel Nyalala ◽  
Liu Gaoqiong

Soft rot of Zantedeschia, caused by Pectobacterium carotovorum subsp. carotovorum (Pcc), has caused a significant worldwide threat to calla lily production. Hence, in order to effectively manage the disease, an intensive management programme aimed at adequte suppression of the pathogen is paramount. In order to investigate the antibacterial effect of a Coptis chinensis extract product against the soft rot- causing bacterium, an in vitro study was set up. Bacterial isolate were obtained from rotting calla lily tubers and maintained in Nutrient Broth under refrigeration. Sterile petri plates containing 15 ml of Nutrient agar were prepared and aseptically inoculated with 0.1 ml an overnight grown culture of a standardized Pectobacterium carotovorum subsp. carotovorum inoculum containing about 1x 108 cfu/ml. The inoculum was spread evenly over the whole surface of the plates. After solidification, 1 ml of the different concentrations of C. chinensis (1, 10, 25, 50 and 100%) were placed individually at the centre of the inoculated petri plates. Positive check was maintained using Streptomycin sulphate (100ppm) and a negative check using sterile distilled water. Eight replicates were maintained for each treatment and the experiment was repeated twice. Results indicated that the lower concentrations of C. chinensis did not cause any inhibition against Pcc. On the other hand, 100% C. chinensis made an inhibition zone comparable to that streptomycin sulphate. Our results demonstrated that C. chinensis has antibacterial activity and therefore feasible for use in crop protection against soft rots caused by Pectobacterium carotovorum subsp. carotovorum.


2021 ◽  
Vol 9 (2) ◽  
pp. 316
Author(s):  
Tongling Ge ◽  
Fatemeh Ekbataniamiri ◽  
Steven B. Johnson ◽  
Robert P. Larkin ◽  
Jianjun Hao

Dickeya and Pectobacterium spp. both cause blackleg and soft rot of potato, which can be a yield-reducing factor to potato production. The purpose of this study was to examine the interaction between these two bacterial genera causing potato infection, and subsequent disease development and yield responses under field conditions. Analysis of 883 potato samples collected in Northeastern USA using polymerase chain reaction determined that Dickeya dianthicola and P. parmentieri were found in 38.1% and 53.3% of all samples, respectively, and that 20.6% of samples contained both D. dianthicola and P. parmentieri. To further investigate the relationship between the two bacterial species and their interaction, field trials were established. Potato seed pieces of “Russet Burbank”, “Lamoka”, and “Atlantic” were inoculated with bacterial suspension of D. dianthicola at 107 colony-forming unite (CFU)/mL using a vacuum infiltration method, air dried, and then planted in the field. Two-year results showed that there was a high correlation (p < 0.01) between yield loss and percent of inoculated seed pieces. In a secondary field trial conducted in 2018 and 2019, seed pieces of potato “Shepody”, “Lamoka” and “Atlantic” were inoculated with D. dianthicola, P. parmentieri, or mixture of both species, and then planted. In 2019, disease severity index, as measured by the most sensitive variety “Lamoka”, was 16.2 with D. dianthicola inoculation, 10.4 with P. parmentieri, 25.4 with inoculation with both bacteria. Two-year data had a similar trend. Thus, D. dianthicola was more virulent than P. parmentieri, but the co-inoculation of the two species resulted in increased disease severity compared to single-species inoculation with either pathogen.


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