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Abstract Pectobacterium carotovorum and Pectobacterium aroidearum represent the primary pathogens causing variable soft rot disease. However, the fundamental defense responses of Pinellia ternata to pathogens remain unclear. Our investigation demonstrated that the disease produced by P. carotovorum is more serious than P. aroidearum. RNA-seq analysis indicated that many cell wall-related genes, receptor-like kinase genes, and resistance-related genes were induced by P. aroidearum and P. carotovorum similarly. But many different regulatory pathways exert a crucial function in plant immunity against P. aroidearum and P. carotovorum, including hormone signaling, whereas more auxin-responsive genes were responsive to P. carotovorum, while more ethylene and gibberellin-responsive genes were responsive to P. aroidearum. 12 GDSL esterase/lipase genes and 3 fasciclin-like arabinogalactan protein genes were specifically upregulated by P. carotovorum, whereas 11 receptor-like kinase genes and 8 disease resistance genes were up-regulated only by P. aroidearum. Among them, a lectin gene (part1transcript/39001) was induced by P. carotovorum and P. aroidearum simultaneously. Transient expression in N. benthamiana demonstrated that the lectin gene improves plant resistance to P. carotovorum. This study offers a comprehensive perspective on P. ternata immunity produced by different soft rot pathogens and reveals the importance of lectin in anti-soft rot of P. ternata for the first time.

Pectobacterium carotovorum and Pectobacterium aroidearum represent the primary pathogens causing variable soft rot disease. However, the fundamental defense responses of Pinellia ternata to pathogens remain unclear. Our investigation demonstrated that the disease produced by P. carotovorum is more serious than P. aroidearum. RNA-seq analysis indicated that many cell wall-related genes, receptor-like kinase genes, and resistance-related genes were induced by P. aroidearum and P. carotovorum similarly. But many different regulatory pathways exert a crucial function in plant immunity against P. aroidearum and P. carotovorum, including hormone signaling, whereas more auxin-responsive genes were responsive to P. carotovorum, while more ethylene and gibberellin-responsive genes were responsive to P. aroidearum. 12 GDSL esterase/lipase genes and 3 fasciclin-like arabinogalactan protein genes were specifically upregulated by P. carotovorum, whereas 11 receptor-like kinase genes and 8 disease resistance genes were up-regulated only by P. aroidearum. Among them, a lectin gene (part1transcript/39001) was induced by P. carotovorum and P. aroidearum simultaneously. Transient expression in N. benthamiana demonstrated that the lectin gene improves plant resistance to P. carotovorum. This study offers a comprehensive perspective on P. ternata immunity produced by different soft rot pathogens and reveals the importance of lectin in anti-soft rot of P. ternata for the first time. [ABSTRACT FROM AUTHOR]

This study was conducted to propose a new strategy for preventing Pectobacterium carotovorum-mediated potato soft rot through the development of a carboxymethyl cellulose (CMC)-based antibacterial coating incorporated with green tea extract (GTE). GTE/CMC films resulted in increased water vapor permeability due to the incorporation of polar groups in GTE. In the antibacterial test against P. carotovorum, the MBC value of GTE was 2 mg/mL. The time-kill assay demonstrated that GTE/CMC (2 × MBC) completely eradicated bacteria within 0.5 h (~6.4 log CFU/mL reduction). The potential of GTE/CMC to prevent potato soft rot was evaluated by monitoring the potato appearance, maceration area, and texture properties. The GTE/CMC-coated potatoes exhibited significantly reduced maceration area and remained firm for 3 days. Moreover, there was no change in the antimicrobial efficacy for 8 weeks. The developed GTE/CMC could be used as a biological coating system for postharvest storage and soft rot prevention. [ABSTRACT FROM AUTHOR]

Numerous functions in pathogenic Pectobacterium are regulated by quorum sensing (QS). Two different aiiA genes isolated from Bacillus sp. A24(aiiAA24) and Bacillus sp. DMS133(aiiADMS133) were used. Both genes encode acyl-homoserine lactonase (AiiA), which disrupts QS in Pectobacterium. To investigate the effect of different AiiAs on the inhibition of Pectobacterium carotovorum pathogenicity, two aiiA genes from different Bacillus strains were cloned and the resulting plasmids pME6863 (aiiAA24) and pME7080 (aiiADMS133) were transformed into P. carotovorum EMPCC cells. The effects of different lactonases on virulence features such as enzymatic activity, twitching and swimming motilities, and production of pellicle and biofilm formation were investigated. In EMPCC/pME6863, twitching and swimming motilities, and pellicle production were significantly reduced compared with EMPCC/pME7080. Quantitative real-time PCR (qRT-PCR) was used to measure virulence gene expression in transformed cells compared with expression levels in wild-type EMPCC. The expression of peh and hrpL genes was greatly reduced in EMPCC/pME6863 compared with EMPCC/pME7080. The sequence alignment and molecular dynamic modeling of two different AiiAA24 and AiiADMS133 proteins suggested that the replacement of proline 210 from AiiAA24 to serine in AiiADMS133 caused the reduction of enzyme activity in AiiADMS133. [ABSTRACT FROM AUTHOR]

"Lenticel rot" is a type of soft rot that develops within potatoes' natural openings due to increased respiration rates. When potatoes are exposed to waterlogged soil and high temperatures, their lenticels expand, providing an access route for pectolytic bacteria. This study is the first to shed light on lenticel rot in Egypt. The study's goal is to investigate how inappropriate watering rates affect the development of lenticel infections. The causal bacteria were identified as Pectobacterium carotovorum subsp. carotovorum using both BIOLOG analysis and DNA sequencing, following the pathogenicity test. In a pot experiment (with 4 kg of soil in each pot), the highest watering rate (1000 mL per pot), combined with soil infestation, resulted in the greatest disease incidence. The ratio of infected (IR) tubers increased from 0.0±0.0 in the treatment without infestation to 65.4±10.7 in the infested treatment (P < 0.001) under the high watering rate. No significant difference in IRs was observed between the different watering rates in non-infested treatments. Additionally, there was no significant difference in IRs between non-infested and infested treatments following regular and moderate watering rates (500 mL and 750 mL, respectively). High irrigation rates altered soil chemistry, decreasing organic matter (OM) and nitrogen (N) availability while increasing phosphorus (P) and potassium (K). In conclusion, the irrigation rate has a significant impact on disease development compared to the sole presence of the pathogen in the soil. This implies that the irrigation rate influences disease development only when the pathogen is actively present. [ABSTRACT FROM AUTHOR]

Various edible polymers [sodium alginate, carboxyl methylcellulose, sodium oleate, liquid paraffin, pectin, pullulan, polyvinyl acetate, and shellac (SHE)] as potato-coating materials and their effect on extending the shelf life of potatoes when combined with an edible coating and UV-C irradiation treatments were evaluated. As a result of the characterization of the edible polymers, SHE was selected as the optimal coating material because it had the best moisture and light barrier properties. SHE coating successfully prevented the greening, respiration, and sprouting of potatoes caused by exposure to light and oxygen. Additionally, it reduced weight loss by inhibiting transpiration on the potato surface. While the SHE coating did not exhibit antimicrobial effects, a significant effect was observed when combined with UV-C irradiation. This study suggests the potential of combined treatment of SHE coating and UV-C irradiation in extending the postharvest quality of potatoes. [ABSTRACT FROM AUTHOR]

Copyright of Egyptian Journal of Botany is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pectobacterium carotovorum causing soft-rot disease requires on-site detection before the distribution of agricultural products. Loop-mediated isothermal amplification (LAMP), which is resistant to food inhibitors, is known for its high detection sensitivity for pathogens and when coupled with lateral flow immunoassay (LFA) enables visualizations. For detection of soft-rot disease, we developed a LAMP-LFA system targeting 16S ribosomal RNA, a partial sequence gene of P. carotovorum subsp. carotovorum. The LAMP-LFA was performed at 60 °C for 50 min followed by hybridization of digoxygenin-labeled LAMP amplicon and biotinylated probe. Detection sensitivity was 3.22 × 101 CFU/mL in pure culture, which specifically detected the target. In Chinese cabbage and potato, the target was detected up to low levels of 1.57 × 102 CFU/g and 1.29 × 102 CFU/g, respectively. This study showed potential applicability as a sensitive point-of-care system for soft-rot disease bacteria detection in agricultural products. [ABSTRACT FROM AUTHOR]

Pectobacterium carotovorum is an economically important phytopathogen causing destructive bacterial soft rot disease in many ornamental plants and fruit and vegetable crops worldwide, including potato. Phage therapy is a promising and environmentally safe alternative to combat bacterial diseases either in the field or during storage. In this study, we characterized two novel P. carotovorum-specific phages, designated PcaP1EGY and PcaP2EGY, isolated from soil in Egypt. We also sequenced the genomes of the two phages, which are the first two complete genome sequences determined for P. carotovorum-infecting podoviruses from Egypt. Phages PcaP1EGY and PcaP2EGY have a high phage titer of 1012 PFU/mL and growth characteristics of an exclusively lytic life cycle. Both phages displayed specificity to and visible lysis activity against all four tested strains of P. carotovorum. They both had a latent period of 30 min and a high burst size of approximately 599 PFU/infected cell for PcaP1EGY and 570 for PcaP2EGY. Additionally, they exhibited remarkable survivability under a wide range of pH, temperature, salt concentration and UV exposure conditions. Both phages, when used alone or in combination, significantly reduced in vitro growth of P. carotovorum after 4 h at all tested multiplicity of infection. Phages PcaP1EGY and PcaP2EGY offered significant protection for both potato tubers and potato plants against soft rot disease caused by P. carotovorum in both our tuber maceration test and greenhouse pot experiment as compared to tubers/plants inoculated with P. carotovorum without receiving any phage treatment. Our results suggest that phages PcaP1EGY and PcaP2EGY have great biocontrol potential against potato soft rot disease caused by P. carotovorum either in the field or during storage after harvest.

Soft rot‐inducing bacterial pathogens are considered among the main biotic constraints on vegetables and annual crops. Most of the bacterial soft rot pathogens are members of Pectobacterium spp. and Dickeya, with the former genus encompassing a continuously increasing number of species varying in geographic distribution and host of isolation. In Iran, Pectobacterium species have rarely been investigated using high‐throughput nucleotide sequence‐based techniques, leaving the genetic diversity of these pathogens mostly undetermined. During 2021, vegetables and annual crops with symptoms of soft rot and maceration were collected from Fars, Hamedan, Isfahan, Khuzestan and Kohgiluyeh‐Boyer‐Ahmad provinces of Iran. Forty‐four pectinolytic bacterial strains were isolated from symptomatic tissues of bell pepper, cabbage, carrot, lettuce, potato and zucchini. The bacterial strains were subjected to pathogenicity and host range assays, specific PCR tests and phylogenetic analysis of three housekeeping genes (dnaX, gapA and leuS). All strains were pathogenic on their host of isolation. Among the 44 pectinolytic strains, 26 strains were identified as members of Pectobacterium based on PCR using the primer pair Y1/Y2. Multilocus sequence analysis confirmed the latter bacterial strains belonging to the genus Pectobacterium and revealed that the strains scattered into four species: P. brasiliense (five strains), P. carotovorum (eight strains), P. polaris (five strains) and P. versatile (eight strains). P. polaris and P. versatile have not previously been reported in the country. Host range assays showed that P. brasiliense and P. carotovorum have a broader host range than the other two species. [ABSTRACT FROM AUTHOR]

Kale has gained popularity as a healthy food choice due to its rich nutrient profile. However, kale production systems are also affected by various pests and diseases, especially plant pathogenic bacteria, such as Pectobacterium carotovorum. The purpose of this research was to investigate the biocontrol activity of the Pseudomonas fluorescens strain SP007s and develop a formulation that provides stability, long shelf life, and disease control, as well as promoting growth in kale; we expect this formulation to have further commercial applications in the cultivation of kale. The results indicated that a unique mixture of paper sludge, sugar sludge, and glycerol at 40% relative humidity promoted SP007 survival for 6 months at room temperature (30 °C) with measures of 5.92 × 106 CFU/g. This treatment maintained the control efficacy of P. carotovorum in infected soil within 28 days of soil drenching. We evaluated the SP007s formula for controlling soft rot disease in greenhouse conditions, and our results revealed that it can reduce the disease in kale by 65.2% and promotes growth in terms of canopy width, shoot height, number of leaves per plant, fresh weight, and dry weight, which were superior to the control. In addition, the formula can induce the accumulation of endogenous salicylic acid and phenolic compounds, as well as a systemic acquired resistance pathway in the plant defense system. Therefore, the formula of SP007s can be a promising novel biocontrol formula for use in kale production, as it promotes plant growth and acts against P. carotovorum causal soft rot disease. [ABSTRACT FROM AUTHOR]

In order to identify the optimal sterilization parameters for HPEF on Pectobacterium carotovorum (P. carotovorum), and preliminarily explore its potential mechanism, the main factors affecting the sterilization effect were identified by measuring the survival rate of P. carotovorum under different treatment conditions of HPEF. Then, the effects of different electric field strengths and pulse duty cycles on the growth curve, fatty acid content of cell membrane, cell membrane permeability, and nucleic acid and protein leakage of P. carotovorum were studied, as well as the differences in sensitivity of P. carotovorum to HPEF in different growth periods. Finally, the kinetic model between electric field strength, pulse duty cycle and the survival rate of P. carotovorum was established. The results showed that the electric field intensity and pulse duty cycle were the main factors affecting the killing of P. carotovorum by HPEF. When the electric field strength was 28 kV/cm and the pulse duty cycle was 36.5%, the antibacterial effect was the strongest, with a reduction of logarithmic value at 1.60. Under the action of HPEF, the delay period of P. carotovorum was prolonged and its growth was inhibited. At the same time, the structure of cell membrane was damaged, and the permeability was increased, leading to the serious leakage of intracellular nucleic acid and protein. In addition, P. carotovorum in different growth period had different sensitivities to HPEF, and logarithmic growth period was the most sensitive. Finally, the kinetic equation was established between the log reduction value of lnS and the electric field strength and pulse duty cycle (y=−0.1067x+0.1166 and y=−0.0895x+0.3249). The equation was in accordance with the first-order kinetic model and reflected the growth relationship of P. carotovorum after HPEF treatment well, which provided data support for the selection of appropriate treatment conditions. In this study, the optimal parameters of HPEF inhibiting P. carotovorum were determined, which provided theoretical data for further realization of HPEF sterilization in the industrial application of postharvest and fresh-cutting industries.

Nanoparticles effectively control most plant pathogens, although research has focused more on their antimicrobial than their nematocidal properties. This study synthesized silver nanoparticles (Ag-NPs) through a green biosynthesis method using an aqueous extract of Ficus sycomorus leaves (FS-Ag-NPs). The nanoparticles were characterized using SEM, TEM, EDX, zeta sizer, and FTIR. The TEM results showed that the synthesized NPs were nanoscale and had an average particle size of 33 ± 1 nm. The elemental silver signal at 3 keV confirmed the formation of Ag-NPs from an aqueous leaf extract of F. sycomorus. The FTIR analysis revealed the existence of several functional groups in the prepared Ag-NPs. The strong-broad band detected at 3430 cm−1 indicated the stretching vibration of -OH (hydroxyl) and -NH2 (amine) groups. The nematocidal activity of biosynthesized FS-Ag-NPs has been evaluated in vitro against the root-knot nematode Meloidogyne incognita at 24, 48, and 72 h. The FS-Ag-NPs at a 200 µg/mL concentration applied for 48 h showed the highest effectiveness, with 57.62% nematode mortality. Moreover, the biosynthesized FS-Ag-NPs were also tested for their antibacterial activity against Pectobacterium carotovorum, P. atrosepticum, and Ralstonia solanacearum. With the application of nanoparticles, the reduction in bacterial growth gradually increased. The most potent activity at all concentrations was found in R. solanacearum, with values of 14.00 ± 2.16, 17.33 ± 2.05, 19.00 ± 1.41, 24.00 ± 1.41, and 26.00 ± 2.83 at concentrations of 5, 10, 15, 20, and 25 µg/mL, respectively, when compared with the positive control (Amoxicillin 25 µg) with a value of 16.33 ± 0.94. At the same time, the nanoparticles showed the lowest reduction values against P. atrosepticum when compared to the control. This study is the first report on the nematocidal activity of Ag-NPs using F. sycomorus aqueous extract, which could be a recommended treatment for managing plant-parasitic nematodes due to its simplicity, stability, cost-effectiveness, and environmentally safe nature. [ABSTRACT FROM AUTHOR]

In recent decades, the use of nanocomposites (NCs) in crop production has been actively studied. We have previously shown that chemically synthesized selenium nanocomposites (Se NCs) based on natural polymeric matrices of arabinogalactan (Se/AG NCs), carrageenan (Se/CAR NCs), and starch (Se/ST NCs) stimulated the growth and development of potatoes in vitro and had an antibacterial effect against the phytopathogen Clavibacter sepedonicus. It is important to confirm that the results obtained in the laboratory are also reproducible in the field conditions of crop cultivation. In addition, the applications of NCs can be expanded if a wider range of their biological activity is revealed, and the effect on other types of cultivated plants and phytopathogens is shown. In this regard, the purpose of this research was to study the effect of nanopriming with Se NCs on the productivity of potatoes in a field experiment, the germination of soybeans, and the viability of the phytopathogen Pectobacterium carotovorum under in vitro conditions. The study included the use of traditional methods of conducting a field experiment in natural growing conditions, also using microbiological cultures and studying the bacterial profile from the endosphere of potato tubers by the imprint method, germinating Glycine max L. soybean seeds after nanopriming in Petri dishes, followed by the measurement of morphometric and biochemical parameters such as the activity of antioxidant enzymes and content of diene conjugates. Based on the results of field experiments, it was found that the preplant treatment of tubers with Se/AG and Se/CAR NCs stimulated a significant increase in the number of stems in potato plants and tubers per plant, but for Se/AG NC, the increase was observed only in 2020 and 2022, and the stimulating effect of Se/AG and Se/CAR NCs on the weight of tubers was observed only in 2020. In the yield structure, the proportion of marketable seed tubers was increased under the influence of all Se NCs. Endosphere cultures from tubers showed that bacteria were present in only 56% of the tubers in the control, while 78% of the tubers obtained from plants grown from seed tubers treated with Se/AG NC and 100% of the tubers from plants grown from seed tubers treated with Se/ST and Se/CAR NCs contained bacteria. The bacteria were represented by both spore-forming Gram-positive and Gram-negative bacteria of various sizes. The results presented in this article and previously published data showed that the maximum diversity of bacteria was observed after treatment with Se/ST NC. Experiments on potatoes showed that Se/AG NC had the greatest biological effect. In addition, the growth-stimulating effect of these NCs on the biomass of the roots of soybean seedlings was shown. It activated the antioxidant enzymes and reduced the level of diene conjugates (DCs), the amount of which increased significantly after seed biopriming with the phytopathogen Pectobacterium carotovorum. The antibacterial effect of Se/AG NC in relation to the P. carotovorum was observed as a reduction in the growth of the bacterial culture, biofilm formation, and dehydrogenase activity of cells. Thus, it has been shown that Se/AG NC has a stimulating effect on such agriculturally important crops as potatoes and soybeans, as well as an antibacterial effect against Gram-negative and Gram-positive phytopathogenic bacteria. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Bioprocess Engineering is the property of Chinese Journal of Bioprocess Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nanoparticles of copper oxide were synthesized from the Spirodela polyrrhiza (greater duckweed) plant. Ultraviolet spectroscopy absorbance of around 400 nm was used for nanoparticle characterization. The presence of copper and oxygen in the biogenic nanoparticles was analyzed by the EDX technique. Based on scanning, and transmission electron microscopy (SEM and TEM) results, copper oxide nanoparticles (CuO NPs) are evenly distributed and spherical, and their sizes are in the 100 nm range. The synthesized nanoparticles of copper oxide were tested for antibacterial, antifungal, and nematicidal effectiveness against plants pest and pathogens. Antifungal and nematicidal activity against pests and plant pathogens was observed, with fungal mycelium reduced by 45–50% and eggs hatching. The findings suggest that plant-based copper oxide nanoparticles could be a potential source of plant pathogen inhibition. From this study, we concluded that synthesized CuO NPs have the potential to serve as a safer alternative for plant disease management. [ABSTRACT FROM AUTHOR]

Terminalia chebula extract-mediated bio-synthesized SnO 2 NPs exhibiting excellent reactive oxygen species (ROS) scavenging activity and potent antimicrobial properties against plant pathogens Pectobacterium carotovorum and Alternaria solani causing soft rot and early blight in tomato crops. [Display omitted] • Eco-friendly synthesis of SnO 2 NPs using Terminalia chebula seed extract as a stabilizing agent. • Superior antimicrobial activity of NPs against disease-causing phytopathogens in tomato crops. • Having the potential for efficient free radical scavenging and oxidative stress management in plants. • A promising and sustainable solution for combating early blight and soft rot disease in tomato crops. Tomato, a globally cultivated crop, is susceptible to early blight (Alternaria solani) and soft rot disease (Pectobacterium carotovorum), resulting in significant yield reductions. In this study, we report the biosynthesis of tin oxide nanoparticles (SnO 2 NPs) via a novel, eco-friendly route and evaluate their efficacy against these phytopathogens. Characterization of SnO 2 NPs revealed a mean particle size of 11.5 nm, uniform distribution, and pure and high crystallinity, as confirmed by TEM, SAED pattern, and P-XRD analysis. The green-synthesized SnO 2 NPs achieved 100 % inhibition of fungal growth at 500 μg/mL and displayed a larger zone of inhibition against Pectobacterium carotovorum than the conventional antibiotic streptomycin. A notable decrease in the exponential phase of the OD600 curve and CFU/mL was further observed with increasing concentrations of NPs. They also demonstrated superior antioxidant properties compared to the standard, achieving over 90 % inhibition at a concentration of 300 μg/mL. The Terminalia chebula seed extract not only acts as a stabilizing agent but also exhibit antimicrobial activity. The synergy between the intrinsic antimicrobial properties of the SnO 2 NPs and the bioactive compounds from the seed extract enhance the overall effectiveness of the nanoparticles against these pathogens. Our findings suggest that green-synthesized SnO 2 NPs offer a promising and sustainable solution for managing early blight and soft rot disease in tomato crops. [ABSTRACT FROM AUTHOR]

ABSTRACTNanoparticles of copper oxide were synthesized from the Spirodela polyrrhiza (greater duckweed) plant. Ultraviolet spectroscopy absorbance of around 400 nm was used for nanoparticle characterization. The presence of copper and oxygen in the biogenic nanoparticles was analyzed by the EDX technique. Based on scanning, and transmission electron microscopy (SEM and TEM) results, copper oxide nanoparticles (CuO NPs) are evenly distributed and spherical, and their sizes are in the 100 nm range. The synthesized nanoparticles of copper oxide were tested for antibacterial, antifungal, and nematicidal effectiveness against plants pest and pathogens. Antifungal and nematicidal activity against pests and plant pathogens was observed, with fungal mycelium reduced by 45–50% and eggs hatching. The findings suggest that plant-based copper oxide nanoparticles could be a potential source of plant pathogen inhibition. From this study, we concluded that synthesized CuO NPs have the potential to serve as a safer alternative for plant disease management.

Salmonella spp. are remarkably adaptable pathogens, and this adaptability allows these bacteria to thrive in a variety of environments and hosts. The mechanisms with which these pathogens establish within a niche amid the native microbiota remain poorly understood. Here, we aimed to uncover the mechanisms that enable Salmonella enterica serovar Typhimurium strain ATCC 14028 to benefit from the degradation of plant tissue by a soft rot plant pathogen, Pectobacterium carotovorum The hypothesis that in the soft rot, the liberation of starch (not utilized by P. carotovorum) makes this polymer available to Salmonella spp., thus allowing it to colonize soft rots, was tested first and proven null. To identify the functions involved in Salmonella soft rot colonization, we carried out transposon insertion sequencing coupled with the phenotypic characterization of the mutants. The data indicate that Salmonella spp. experience a metabolic shift in response to the changes in the environment brought on by Pectobacterium spp. and likely coordinated by the csrBC small regulatory RNA. While csrBC and flhD appear to be of importance in the soft rot, the global two-component system encoded by barA sirA (which controls csrBC and flhDC under laboratory conditions) does not appear to be necessary for the observed phenotype. Motility and the synthesis of nucleotides and amino acids play critical roles in the growth of Salmonella spp. in the soft rot.IMPORTANCE Outbreaks of produce-associated illness continue to be a food safety concern. Earlier studies demonstrated that the presence of phytopathogens on produce was a significant risk factor associated with increased Salmonella carriage on fruits and vegetables. Here, we genetically characterize some of the requirements for interactions between Salmonella and phytobacteria that allow Salmonella spp. to establish a niche within an alternate host (tomato). Pathways necessary for nucleotide synthesis, amino acid synthesis, and motility are identified as contributors to the persistence of Salmonella spp. in soft rots.

For many decades, members in the genus Streptomyces have been considered the principal microbial producers of secondary metabolites with antibiotic activity. In this study, we evaluated the inhibitory activity of a cell-free supernatant produced by Streptomyces sp. CACIS1.16CA against human and plant bacterial pathogens. We also assessed the thermal stability of the compounds. An initial screening to evaluate the antibacterial activity of compounds diffused from a CACIS-1.16CA culture into agar discs found inhibitory effects against Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus pumilus, and Pectobacterium carotovorum. A cell-free supernatant from cultured CACIS-1.16CA confirmed the inhibition effects on the susceptible pathogens. Thermally treating the supernatant did not significantly affect the inhibitory activity, indicating Streptomyces sp. CACIS-1.16CA produces some thermally stable antibacterial metabolites. This antibacterial activity is consistent with the detection of biosynthetic gene clusters for polyketide synthase Types I and II and non-ribosomal peptide synthase. [ABSTRACT FROM AUTHOR]

The protective effect of bacteriophage suspensions (Ds3CZ + Ds20CZ and PcCB7V + PcCB251) on phytopathogenic bacteria causing soft rot of potato tubers, namely Dickeya dianthicola (D50, D200) and Pectobacterium carotovorum (P87, P224), was observed in ex vivo and in vitro experiments. Ex vivo tests were performed (with air access) on potato slices, on cylindrical cuts from the center of the tubers, and directly in whole potato tubers. In vitro experiments were carried out in a liquid medium using RTS-8 bioreactors, where bacterial growth was monitored as optical density. In particular, the inhibitory effects of phages were confirmed in experiments on potato slices, where suppression of rot development was evident at first glance. Phage treatment against selected bacteria positively affected potato hardness. Hardness of samples treated with bacteria only was statistically significantly reduced (p < 0.05 for D50 and p < 0.001 for D200 and P87). Ex vivo experiments confirmed significant inhibition of P87 symptom development, partial inhibition of D200 and D50 in phage-treated tubers, and no effect was observed for P224. The inhibitory effect of phages against bacteria was not observed in the in vitro experiment. [ABSTRACT FROM AUTHOR]

The pathogenic bacterium Pectobacterium carotovorum causes soft rot in cabbage and significantly reduces plant yield. In this study, we employed Mhonia fortunei extracts to synthesis silver nanoparticles (Mf-AgNPs) and investigated their functions against P. carotovorum. The results showed that the surface plasmon resonance (SPR) peak of AgNP was 412nm under optimal synthesis conditions. Furthermore, the results of Scanning electron microscope-Energy dispersive spectrometer (SEM-EDS) and High-resolution transmission electron microscopy (HR-TEM) revealed that the Mf-AgNPs had a spherical structure with an average diameter of 13.19nm and the content of Ag0 ions accounted for 82.68% of the total elemental content. The X-Ray diffraction (XRD) results confirmed that AgNPs had a face-centered cubic (FCC) crystal structure, while Fourier transform infrared spectroscopy (FTIR) results indicated the presence of various biomolecules as reducing and stabilizing agents on the AgNP surface. Antibacterial activity was first evaluated by an inhibitory zone test, which revealed that 500 μgml-1 of AgNPs had antibacterial activity against P. carotovorum and four model bacteria including Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa, respectively with an antibacterial function comparable to 1mM AgNO3 solution. The Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for P. carotovorum were 8 μgml-1, respectively. Furthermore, AgNPs at 8 μgml-1 completely inhibited the growth of P. carotovorum, decreased their tolerance to 0.25mM H2O2 as well as considerably reduced colony formation after 1h of treatment and thereafter. Treatment with Mf-AgNPs resulted in bacterial cell membrane destruction and biofilm formation inhibition, respectively. With an FIC (fractional inhibitory concentration) index of 0.174, AgNP and zhongshengmycin showed a significant synergistic effect. The infection of P. carotovorum to cabbage explants was significantly inhibited in vitro by a combination of 2 μgml-1 Mf-AgNP and 5 μgml-1 zhongshengmycin. In conclusion, the synthesized Mf-AgNP exhibited significant antibacterial activity against P. carotovorum. [ABSTRACT FROM AUTHOR]

ABSTRACT Pectobacterium carotovorum is an economically important phytopathogen and has been identified as the major causative agent of bacterial soft rot in carrots. Control of this phytopathogen is vital to minimizing carrot harvest losses. As fully efficient control measures to successfully avoid the disease are unavailable, the phage-mediated biocontrol of the pathogen has recently gained scientific attention. In this study, we present a comprehensive characterization of the P. carotovorum phage vB_PcaM_P7_Pc (abbreviated as P7_Pc) that was isolated from infected carrot samples with characteristic soft rot symptoms, which were obtained from storage facilities at market places in Gampaha District, Sri Lanka. P7_Pc is a myovirus, and it exhibits growth characteristics of an exclusively lytic life cycle. It showed visible lysis against four of the tested P. carotovorum strains and one Pectobacterium aroidearum strain. This phage also showed a longer latent period (125 min) than other related phages; however, this did not affect its high phage titter (>1010 PFU/mL). The final assembled genome of P7_Pc is 147,299 bp in length with a G+C content of 50.34%. Of the 298 predicted open reading frames (ORFs) of the genome of P7_Pc, putative functions were assigned to 53 ORFs. Seven tRNA-coding genes were predicted in the genome, while the genome lacked any major genes coding for lysogeny-related products, confirming its virulent nature. The P7_Pc genome shares 96.12% and 95.74% average nucleotide identities with Cronobacter phages CR8 and PBES02, respectively. Phylogenetic and phylogenomic analyses of the genome revealed that P7_Pc clusters well within the clade with the members representing the genus Certrevirus. Currently, there are only 4 characterized Pectobacterium phages (P. atrosepticum phages phiTE and CB7 and Pectobacterium phages DU_PP_I and DU_PP_IV) that are classified under the genus, making the phage P7_Pc the first reported member of the genus isolated using the host bacterium P. carotovorum. The results of this study provide a detailed characterization of the phage P7_Pc, enabling its careful classification into the genus Certrevirus. The knowledge gathered on the phage based on the shared biology of the genus will further aid in the future selection of phage P7_Pc as a biocontrol agent. IMPORTANCE Bacterial soft rot disease, caused by Pectobacterium spp., can lead to significant losses in carrot yields. As current control measures involving the use of chemicals or antibiotics are not recommended in many countries, bacteriophage-mediated biocontrol strategies are being explored for the successful control of these phytopathogens. The successful implementation of such biocontrol strategies relies heavily upon the proper understanding of the growth characteristics and genomic properties of the phage. Further, the selection of taxonomically different phages for the formulation of phage cocktails in biocontrol applications is critical to combat potential bacterial resistance development. This study was conducted to carefully characterize and resolve the phylogenetic placement of the P. carotovorum phage vB_PcaM_P7_Pc by using its biological and genomic properties. Phage P7_Pc has a myovirus morphotype with an exclusively lytic life cycle, and the absence of genes related to lysogeny, toxin production, and antibiotic resistance in its genome confirmed its suitability to be used in environmental applications. Furthermore, P7_Pc is classified under the genus Certrevirus, making it the first reported phage of the genus of the host species, P. carotovorum.

Kale has gained popularity as a healthy food choice due to its rich nutrient profile. However, kale production systems are also affected by various pests and diseases, especially plant pathogenic bacteria, such as Pectobacterium carotovorum. The purpose of this research was to investigate the biocontrol activity of the Pseudomonas fluorescens strain SP007s and develop a formulation that provides stability, long shelf life, and disease control, as well as promoting growth in kale; we expect this formulation to have further commercial applications in the cultivation of kale. The results indicated that a unique mixture of paper sludge, sugar sludge, and glycerol at 40% relative humidity promoted SP007 survival for 6 months at room temperature (30 °C) with measures of 5.92 × 106 CFU/g. This treatment maintained the control efficacy of P. carotovorum in infected soil within 28 days of soil drenching. We evaluated the SP007s formula for controlling soft rot disease in greenhouse conditions, and our results revealed that it can reduce the disease in kale by 65.2% and promotes growth in terms of canopy width, shoot height, number of leaves per plant, fresh weight, and dry weight, which were superior to the control. In addition, the formula can induce the accumulation of endogenous salicylic acid and phenolic compounds, as well as a systemic acquired resistance pathway in the plant defense system. Therefore, the formula of SP007s can be a promising novel biocontrol formula for use in kale production, as it promotes plant growth and acts against P. carotovorum causal soft rot disease.

The abuse of agricultural antibiotics has led to the emergence of drug-resistant phytopathogens. Rifampicin and streptomycin and streptomycin resistance Pectobacterium carotovorum subsp. carotovorum (PccS1) was obtained from pathological plants in a previous experiment. Rheum tanguticum, derived from the Chinese plateau area, exhibits excellent antibacterial activity against PccS1, yet the action mode has not been fully understood. In present text, the cell wall integrity of the PccS1 was tested by the variation of the cellular proteins, SDS polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometer (FTIR) characteristics. Label-free quantitative proteomics was further used to identify the DEPs in the pathogen response to treatment with Rheum tanguticum Maxim. ex Balf. extract (abbreviated as RTMBE). Based on the bioinformatics analysis of these different expressed proteins (DEPs), RTMBE mainly inhibited some key protein expressions of beta-Lactam resistance, a two-component system and phosphotransferase system. Most of these membrane proteins were extraordinarily suppressed, which was also consistent with the morphological tests. In addition, from the downregulated flagellar motility related proteins, it was also speculated that RTMBE played an essential antibacterial role by affecting the swimming motility of the cells. The results indicated that Rheum tanguticum can be used to attenuate the virulence of the drug-resistant phytopathogenic bacteria. [ABSTRACT FROM AUTHOR]

Pectobacterium carotovorum subsp. carotovorum (PCC) is a notorious plant pathogen responsible for severe soft rot in kimchi cabbage, which results in significant economic losses. To detect PCC rapidly and accurately in kimchi cabbage, we developed a surface-enhanced Raman scattering (SERS) substrate on which silver nanospheres (AgNSs), nanowires (AgNWs), and nanoseeds are combined on a polydimethylsiloxane (PDMS) platform. The incorporation of Ag nanoseeds creates a higher density of hotspots, which ensures a low detection limit of 1.001 CFU/mL. Electron microscopy and spectroscopic analyses confirmed the successful fabrication of the substrate and its enhanced sensitivity. The SERS substrate exhibits excellent selectivity by effectively distinguishing PCC from other bacteria commonly found in kimchi cabbage. The substrate gives rise to strong Raman signals across PCC concentrations ranging from 101 to 106 CFU/mL. Additionally, a predictive model was developed for accurately detecting PCC in real kimchi cabbage samples, and the results were validated by polymerase chain reaction measurements. A sensitive, selective, and rapid approach for PCC detection in kimchi cabbage that offers a promising improvement over existing methodologies is presented. [Display omitted] [ABSTRACT FROM AUTHOR]

Introducción. La Pudrición Suave del Fruto (PSF) es una enfermedad precosecha que afecta a las musáceas. En renovación de plantaciones, las pérdidas por esta enfermedad alcanzan desde 0,3 hasta 1,2 t.ha-1.año-1 de fruta. Objetivo. Describir los síntomas de la PSF, a partir de los agentes asociados para evaluar a nivel in vitro posibles alternativas microbiológicas y químicas para su control. Materiales y métodos. La descripción de los síntomas, identificación de agentes asociados y pruebas de patogenicidad se realizaron a partir del análisis de tejido enfermo de frutos de 11 y 12 semanas de edad. El potencial de 13 formulaciones comerciales de cepas puras y mezclas de microorganismos, 4 formulaciones de cobre y una formulación de yodo fueron evaluadas contra los agentes asociados a la PSF, mediante la metodología del doble enfrentamiento. Se midió el diámetro menor y mayor del anillo de inhibición, a las 24, 48 y 120 horas. Se realizó un análisis de variancia (ANDEVA) con una prueba LSD Fisher y una probabilidad del 5%. Resultados. El agente asociado a PSF fue aislado de tejido enfermo e identificado como Erwinia chrysanthemi (Dickeya chrysanthemi). Debido a que siempre fue aislada del tejido enfermo, su patogenicidad se logró comprobar mediante los postulados de Koch. Se presume una participación conjunta de Erwinia carotovora (Pectobacterium carotovorum) debido a que siempre fue asilada del tejido enfermo. El mejor efecto antagonista in vitro sobre Erwinia chrysanthemi se obtuvo con los microorganismos Bacillus pumilus cepa QST2808 y Bacillus subtilis cepa QST713. El mejor efecto in vitro de las fuentes químicas evaluadas se obtuvo con la dosis completa y media dosis de sulfato de cobre al 28,8%, y la dosis más alta de Iodo-Etanol al 2,5%. Conclusión. Se logró identificar el agente asociado a la enfermedad, además, se proponen alternativas microbiológicas y químicas con potencial inhibitorio in vitro para considerarse en pruebas de campo.

Chinese cabbage (Brassica rapa subsp. pekinensis) suffers from soft rot disease caused by Pectobacterium carotovorum (Pc). To uncover the mechanisms underlying the defense response of Chinese cabbage to Pc, we constructed a suppression subtractive hybridization (SSH) library from Pc-infected cabbage and obtained 1 919 non-redundant expressed sequence tags (ESTs), which were used for cDNA microarray. We detected 800 differentially expressed genes (DEGs) in cabbage at different time points post-Pc inoculation, which were further confirmed by quantitative real-time PCR. One quarter of these DEGs were involved in the biotic stress pathways visualized by MapMan. Among them, 8, 8, 1, 3, and 2 DEGs were related to jasmonic acid (JA), ethylene (ET), JA+ET, auxin, and abscisic acid (ABA) signaling pathways, respectively, while no DEG was detected for salicylic acid (SA) signaling. Assessment of phytohormone production in the Pc-infected leaves showed that JA and ET production was increased, while SA production was decreased. Treatment with JA, methyl jasmonate (MeJA), the ET precursor 1-aminocyclopropane-1-carboxylate (ACC), or combinations thereof, reduced the disease severity, and the JA and JA+ACC treatments were superior and performed equally well. Our findings suggest that JA and ET may act synergistically against Pc infection in Chinese cabbage, and JA-mediated signaling might be the most significant.

Nanoparticles effectively control most plant pathogens, although research has focused more on their antimicrobial than their nematocidal properties. This study synthesized silver nanoparticles (Ag-NPs) through a green biosynthesis method using an aqueous extract of Ficus sycomorus leaves (FS-Ag-NPs). The nanoparticles were characterized using SEM, TEM, EDX, zeta sizer, and FTIR. The TEM results showed that the synthesized NPs were nanoscale and had an average particle size of 33 ± 1 nm. The elemental silver signal at 3 keV confirmed the formation of Ag-NPs from an aqueous leaf extract of F. sycomorus. The FTIR analysis revealed the existence of several functional groups in the prepared Ag-NPs. The strong-broad band detected at 3430 cm−1 indicated the stretching vibration of -OH (hydroxyl) and -NH2 (amine) groups. The nematocidal activity of biosynthesized FS-Ag-NPs has been evaluated in vitro against the root-knot nematode Meloidogyne incognita at 24, 48, and 72 h. The FS-Ag-NPs at a 200 µg/mL concentration applied for 48 h showed the highest effectiveness, with 57.62% nematode mortality. Moreover, the biosynthesized FS-Ag-NPs were also tested for their antibacterial activity against Pectobacterium carotovorum, P. atrosepticum, and Ralstonia solanacearum. With the application of nanoparticles, the reduction in bacterial growth gradually increased. The most potent activity at all concentrations was found in R. solanacearum, with values of 14.00 ± 2.16, 17.33 ± 2.05, 19.00 ± 1.41, 24.00 ± 1.41, and 26.00 ± 2.83 at concentrations of 5, 10, 15, 20, and 25 µg/mL, respectively, when compared with the positive control (Amoxicillin 25 µg) with a value of 16.33 ± 0.94. At the same time, the nanoparticles showed the lowest reduction values against P. atrosepticum when compared to the control. This study is the first report on the nematocidal activity of Ag-NPs using F. sycomorus aqueous extract, which could be a recommended treatment for managing plant-parasitic nematodes due to its simplicity, stability, cost-effectiveness, and environmentally safe nature.

Many Gram-negative bacteria use small signal molecules, such as N -acyl-homoserine lactones (AHLs), to communicate with each other and coordinate their collective behaviors. Recently, increasing evidence has demonstrated that long-chained quorum-sensing signals play roles in priming defense responses in plants. Our previous work indicated that a short-chained signal, N -3-oxo-octanoyl homoserine lactone (3OC8-HSL), enhanced Arabidopsis resistance to the hemi-biotrophic bacteria Pseudomonas syringae pv. tomato DC3000 through priming the salicylic acid (SA) pathway. Here, we found that 3OC8-HSL could also prime resistance to the necrotrophic bacterium Pectobacterium carotovorum ssp. carotovorum (Pcc) through the jasmonic acid (JA) pathway, and is dependent on auxin responses, in both Chinese cabbage and Arabidopsis. The subsequent Pcc invasion triggered JA accumulation and increased the down-stream genes' expressions of JA synthesis genes (LOX , AOS , and AOC) and JA response genes (PDF1.2 and VSP2). The primed state was not observed in the Arabidopsis coi1 - 1 and jar1-1 mutants, which indicated that the primed resistance to Pcc was dependent on the JA pathway. The 3OC8-HSL was not transmitted from roots to leaves and it induced indoleacetic acid (IAA) accumulation and the DR5 and SAUR auxin-responsive genes' expressions in seedlings. When Arabidopsis and Chinese cabbage roots were pretreated with exogenous IAA (10 μM), the plants had activated the JA pathway and enhanced resistance to Pcc , which implied that the JA pathway was involved in AHL priming by coordinating with the auxin pathway. Our findings provide a new strategy for the prevention and control of soft rot in Chinese cabbage and provide theoretical support for the use of the quorum-sensing AHL signal molecule as a new elicitor. [ABSTRACT FROM AUTHOR]

The cpxR gene, encoding a new cytoplasmic response regulator, which effects virulence, biofilm formation, chemotaxis, resistance to antimicrobials, and controls soft rot, was amplified by the polymerase chain reaction, cloned into the prokaryotic expression vector pET‐15b, and expressed through the induction of isopropyl‐β‐d‐thiogalactoside in Escherichia coli BL21 (DE3). Then, highly purified and stable CpxR protein was produced by nickel affinity chromatography and fast protein liquid chromatography, digested by thrombin and identified by Western blotting. Furthermore, the structure of the CpxR protein was estimated by circular dichroism spectroscopy and SWISS‐MODEL. The CpxR protein was a functional part in signal transduction and bacterial resistance for Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The resear ch of the protein stability indicated the CpxR protein had excellent thermal stability and was suitable for crystallization. Then the small crystals of CpxR protein were found in the crystallizing tank. The latest 34 cpxR sequences from the public database were selected and analyzed by molecular clustering and multisequence alignment. These cpxR sequences were roughly divided into four categories. These results laid an important foundation for the further structural study of the CpxR protein. [ABSTRACT FROM AUTHOR]

Abstract Background Several chemical bactericides were applied for controlling soft rot bacteria, Pectobacterium carotovorum subsp. carotovorum, which causes the destructive soft rot disease to many economically important vegetables, but because of their toxic hazards on human and environment became limit. The biocontrol was applied to control many plant pathogens. Therefore, this work is aimed to study the antagonistic activity of bacterial agents, i.e. Bacillus subtilis, Bacillus pumilus, Bacillus megaterium and Pseudomonas fluorescens, and fugal agents, i.e. Trichoderma harzianum, Trichoderma viride and Trichoderma virens, to control bacterial soft rot disease under in vitro and in vivo tests. Results The tested treatments could protect the potato tubers against the development of soft rot. T. viride and T. virens were highly effective in reducing soft rot symptoms on inoculated potato tuber slices, when applied at the same time or 2 h before pathogen inoculation, while B. megaterium and T. harzianum were highly effective when applied at the same time or 2 h after pathogen inoculation. In whole potato tubers technique, B.pumilus highly protected the stored potato tuber under artificially infection conditions, than P. fluorescens, T. harzianum, B. subtilis, T. viride, T. virens and B. megaterium, respectively. Conclusion Application of fungal agents or specify the bacterial species can play an important role in controlling bacterial soft rot disease in vegetables and increase the stored periods of potato tubers under storage conditions without any toxic effects.

Abstract Background Blackleg and tuber soft rot are among the most important potato diseases caused by the bacteria belonging to the genera Pectobacterium. This pathogen causes significant economic losses each year. The antagonistic activity of different bacterial cultures against this pathogen was studied. Results Six hundred eight bacterial cultures isolated from potato tubers and rhizosphere soils procured from different locations across Morocco were tested for their antagonistic activity against Pectobacterium carotovorum. Forty isolates, all originating from tubers, showed positive antagonistic activity during preliminary screening. Among the 40 isolates, 10 were found to have a symptom suppression superior to 90%. Of the 10 isolates, 9 showed clear zone in the agar medium (in vitro test), with differences between antagonist’s inhibition diameter. For the in vivo test, 8 isolates induced total suppression of soft rot on potato slices (in vivo test). The other 2 biocontrol strains (Amo-23 and Atd-2) were capable to minimize soft rot symptoms of up to 94.4 and 96.2%, respectively. Among the selected strains for in planta experiment, 6 strains (namely Ame-4, Atd-2, Atd-4, Ag-216, Al-51, and Ama-501) showed total reduction of disease symptoms. Biochemical and molecular tests identified 8 strains of Bacillus sp. and 2 strains of Pseudomonas sp. Conclusions The results of the in vivo and the greenhouse experiments indicated that the selected isolates had a greatly significant effectiveness for suppressing blackleg and soft rot symptoms. The selected isolates could, therefore, be used as a biocontrol agent against blackleg and soft rot of potato.

Abstract Background Soft rot disease caused by Pectobacterium carotovorum was observed in various crops which lead to yield shortages and economic losses. Main body Therefore, both in vitro and in vivo experiments, aim to assess the effect of nanoparticles and biological treatments to control soft rot disease in sugar beet plant. The treatments comprised three silver nanoparticles (Ag NPs) concentrations (50, 75, and 100 ppm), three Spirulina platensis extract concentrations (50, 75, and 100%), and Bacillus subtilis (1 × 109 CFU ml) 100%. Under in vitro condation, results of the antibacterial activity showed that the zones of inhibition recorded 4.33 cm for 100 ppm Ag NPs, 0.43 cm for 100% algal extract, and 0.2 cm for bacterial treatments. Also, disease incidence % of bacterial soft rot was significantly decreased in all treatments in pot and field experiments. For resistant enzymes activity, B. subtilis 100% showed the most effect (84 mg min−1), followed by S. platensis extract 75%, (57 mg min−1), and Ag NPs 75 ppm (44 mg min−1), for poly phenol oxidase (PPO) at 81 days after sowing (DAS), but at 102 DAS revealed opposite results. On the contrary, peroxidase (PO) at 81 DAS showed different effects where treatment with S. platensis extract 100% increased it significantly (0.546 mg min−1) compared to control (0.535 mg min−1). The same trend was observed at 102 DAS. These results were reflected on sugar quality where Ag NPs 100 ppm treatment recorded the highest significant value (20.5%) followed by S. platensis 75% (19 %); however, the differences among them were not statistically significant. Conclusion This study indicated that the potential benefits of using silver nanoparticles and two biological treatments to control soft rot disease in sugar beet (Beta vulgaris L).

Many Gram-negative bacteria use small signal molecules, such as N-acyl-homoserine lactones (AHLs), to communicate with each other and coordinate their collective behaviors. Recently, increasing evidence has demonstrated that long-chained quorum-sensing signals play roles in priming defense responses in plants. Our previous work indicated that a short-chained signal, N-3-oxo-octanoyl homoserine lactone (3OC8-HSL), enhanced Arabidopsis resistance to the hemi-biotrophic bacteria Pseudomonas syringae pv. tomato DC3000 through priming the salicylic acid (SA) pathway. Here, we found that 3OC8-HSL could also prime resistance to the necrotrophic bacterium Pectobacterium carotovorum ssp. carotovorum (Pcc) through the jasmonic acid (JA) pathway, and is dependent on auxin responses, in both Chinese cabbage and Arabidopsis. The subsequent Pcc invasion triggered JA accumulation and increased the down-stream genes’ expressions of JA synthesis genes (LOX, AOS, and AOC) and JA response genes (PDF1.2 and VSP2). The primed state was not observed in the Arabidopsis coi1-1 and jar1-1 mutants, which indicated that the primed resistance to Pcc was dependent on the JA pathway. The 3OC8-HSL was not transmitted from roots to leaves and it induced indoleacetic acid (IAA) accumulation and the DR5 and SAUR auxin-responsive genes’ expressions in seedlings. When Arabidopsis and Chinese cabbage roots were pretreated with exogenous IAA (10 μM), the plants had activated the JA pathway and enhanced resistance to Pcc, which implied that the JA pathway was involved in AHL priming by coordinating with the auxin pathway. Our findings provide a new strategy for the prevention and control of soft rot in Chinese cabbage and provide theoretical support for the use of the quorum-sensing AHL signal molecule as a new elicitor.

Plants have developed complex defense mechanisms to cope with microbial pathogens. Pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) are perceived by pattern recognition receptors (PRRs), leading to the activation of defense. While substantial progress has been made in understanding the activation of plant defense by PAMPs and DAMPs recognition in tracheophytes, far less information exists on related processes in early divergent plants like mosses. The aim of this study was to identify genes that were induced in P. patens in response to elicitors of Pectobacterium carotovorum subsp. carotovorum, using a cDNA suppression subtractive hybridization (SSH) method. A total of 239 unigenes were identified, including genes involved in defense responses related to the shikimate, phenylpropanoid, and oxylipin pathways. The expression levels of selected genes related to these pathways were analyzed using quantitative RT-PCR, confirming their rapid induction by P.c. carotovorum derived elicitors. In addition, P. patens induced cell wall reinforcement after elicitor treatment by incorporation of phenolic compounds, callose deposition, and elevated expression of Dirigent-like encoding genes. Small molecule defense markers and phytohormones such as cinnamic acid, 12-oxo-phytodienoic acid, and auxin levels all increased in elicitor-treated moss tissues. In contrast, salicylic acid levels decreased while abscisic acid levels remained unchanged. P. patens reporter lines harboring an auxin-inducible promoter fused to β-glucuronidase revealed GUS activity in protonemal and gametophores tissues treated with elicitors of P.c. carotovorum, consistent with a localized activation of auxin signaling. These results indicate that P. patens activates the shikimate, phenylpropanoid, oxylipins, and auxin pathways upon treatment with P.c. carotovorum derived elicitors.

Pectobacterium carotovorum is one of the most serious pectolytic bacterial pathogens causing significant pre- and postharvest soft rot diseases on a variety of agroeconomic fruits and vegetables worldwide. Application of chemical pesticides for controlling the postharvest diseases is still insufficient and unacceptable by consumers. The effect of sodium benzoate (C6H5COONa) (SBN) was evaluated against the growth of P. carotovorum utilizing the highly pathogenic strain BR03, confirmed molecularly using dnaA primers. The inhibition zone was the greatest when P. carotovorum was treated with 600 mM SBN both at pH 7.5 and 7.0. Flow cytometry (distinguishing live and dead bacterial cells) and the development of bacterial colonies on Petri plates confirmed the bactericidal action of SBN. In addition, these results validated that bacterial cells were killed when treated with 600 mM SBN. The biofilm formation was completely inhibited and destroyed following exposure to 600 mM SBN after a 24-h incubation period and the absorbance readings were reduced as the concentration of SBN increased. Disease severity on inoculated tomato fruits decreased in comparison with the control fruit at either 4 or 25 °C. SBN is safe for human health and commonly used in industries as a food preservative. SBN can be an effective alternative method for controlling soft rot diseases on tomato fruits. [ABSTRACT FROM AUTHOR]

This study was aimed at identification and prevalence of potato soft rot and black leg disease agent in the potato production areas of Tokat province. In March-August 2018, 67 field surveys were carried out in Central, Turhal, Zile, Pazar, Erbaa, Niksar, Artova and Basciftlik districts of Tokat. The disease incidences were 0.25%, 0.33%, 0.31%, 0.5%, 1%, and 8% in Central, Erbaa, Niksar, Pazar, Turhal, and Zile district, respectively. In Artova and Basciftlik districts, no disease was encountered. The following tests, pectolytic activity on potato, gram reaction, catalase, oxidase, growth at 37°C and 39°C, salt tolerance, hypersensitivity reaction were applied to isolates obtained from diseased plant and tuber samples. In the PCR assay, 19 isolates were produced 434 bp product with Y1/Y2 primers specific to Pectobacterium spp., and 3 isolates were produced 420 bp product with ADE1/ADE2 primers specific to Dickeya spp. The isolates resulted positive with Y1/Y2 primers weren’t produced PCR product with ECA1/ECA2 primers specific to Pectobacterium atrosepticum. According to this, 19 isolates were identified as Pectobacterium carotovorum. With this study, the causal agent of potato blackleg and soft rot disease have been identified in the potato production areas of Tokat. Further studies will be conducted to determine the species and subspecies level of the pathogens using specific primers.

Potato is the third most important food crop worldwide. Potato production suffers from severe diseases caused by multiple detrimental plant pathogens, and broad-spectrum disease resistance genes are rarely identified in potato. Here we identified the potato non-specific lipid transfer protein StLTPa, which enhances species none-specific disease resistance against various pathogens, such as the oomycete pathogen Phytophthora infestans, the fungal pathogens Botrytis cinerea and Verticillium dahliae, and the bacterial pathogens Pectobacterium carotovorum and Ralstonia solanacearum. The StLTPa overexpression potato lines do not show growth penalty. Furthermore, we provide evidence that StLTPa binds to lipids present in the plasma membrane (PM) of the hyphal cells of P. infestans, leading to an increased permeability of the PM. Adding of PI(3,5)P 2 and PI(3)P could compete the binding of StLTPa to pathogen PM and reduce the inhibition effect of StLTPa. The lipid-binding activity of StLTPa is essential for its role in pathogen inhibition and promotion of potato disease resistance. We propose that StLTPa enhances potato broad-spectrum disease resistance by binding to, and thereby promoting the permeability of the PM of the cells of various pathogens. Overall, our discovery illustrates that increasing the expression of a single gene in potato enhances potato disease resistance against different pathogens without growth penalty., (© 2024 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)

The protective effect of bacteriophage suspensions (Ds3CZ + Ds20CZ and PcCB7V + PcCB251) on phytopathogenic bacteria causing soft rot of potato tubers, namely Dickeya dianthicola (D50, D200) and Pectobacterium carotovorum (P87, P224), was observed in ex vivo and in vitro experiments. Ex vivo tests were performed (with air access) on potato slices, on cylindrical cuts from the center of the tubers, and directly in whole potato tubers. In vitro experiments were carried out in a liquid medium using RTS-8 bioreactors, where bacterial growth was monitored as optical density. In particular, the inhibitory effects of phages were confirmed in experiments on potato slices, where suppression of rot development was evident at first glance. Phage treatment against selected bacteria positively affected potato hardness. Hardness of samples treated with bacteria only was statistically significantly reduced (p < 0.05 for D50 and p < 0.001 for D200 and P87). Ex vivo experiments confirmed significant inhibition of P87 symptom development, partial inhibition of D200 and D50 in phage-treated tubers, and no effect was observed for P224. The inhibitory effect of phages against bacteria was not observed in the in vitro experiment.

Abstract Forty-two bacterial isolates were collected from soft-rotted potato tubers originating from four governorates in Egypt. Their phenotypic and genetic characteristics were studied. The phenotypic identification resulted in grouping the studied isolates into five different species and/or genera including Pectobacterium sp., Bacillus sp., Dickeya sp., Pseudomonas sp. (1), and Pseudomonas sp. (2). The molecular identification of the 10 isolates of them were pathogenic to potato tubers and other hosts. More specific identification of the later 10 isolates, using two specific primers for P. carotovorum subsp. carotovorum (Pcc) and the reference strain PccY46 (Acc. No. KP187511.1), revealed that all these isolates had yielded 220–272-bp DNA fragments identical to the 16S rRNA gene of PccY46. Phylogenetic analysis showed sequence similarity ranging from 87 to 98%, which confirmed the genetic variation among the 10 tested strains of Pcc. The isolates were distributed in four major clusters, each subdivided into a few sub-clusters. In another experiment, two different essential oils (peppermint and clove oils) plus a nano-Cu-based fungicide (Tango®), in comparison to the two different antibiotics and the two copper fungicides, were evaluated for their potential management on the three most severe bacterial isolates (Pcc1, Pcc5, and Pcc10). Results of in vivo experiment showed that clove oil was the most effective, where it caused a reduction of disease severity (0.0%) on potato tubers, 4 days post artificial inoculation.

The abuse of agricultural antibiotics has led to the emergence of drug-resistant phytopathogens. Rifampicin and streptomycin and streptomycin resistance Pectobacterium carotovorum subsp. carotovorum (PccS1) was obtained from pathological plants in a previous experiment. Rheum tanguticum, derived from the Chinese plateau area, exhibits excellent antibacterial activity against PccS1, yet the action mode has not been fully understood. In present text, the cell wall integrity of the PccS1 was tested by the variation of the cellular proteins, SDS polyacrylamide gel electrophoresis (SDS-PAGE), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometer (FTIR) characteristics. Label-free quantitative proteomics was further used to identify the DEPs in the pathogen response to treatment with Rheum tanguticum Maxim. ex Balf. extract (abbreviated as RTMBE). Based on the bioinformatics analysis of these different expressed proteins (DEPs), RTMBE mainly inhibited some key protein expressions of beta-Lactam resistance, a two-component system and phosphotransferase system. Most of these membrane proteins were extraordinarily suppressed, which was also consistent with the morphological tests. In addition, from the downregulated flagellar motility related proteins, it was also speculated that RTMBE played an essential antibacterial role by affecting the swimming motility of the cells. The results indicated that Rheum tanguticum can be used to attenuate the virulence of the drug-resistant phytopathogenic bacteria.