scholarly journals Study of quarantine plant diseases in Georgia

2018 ◽  
pp. 256-261
Author(s):  
G. Meparishvili ◽  
L. Gorgiladze ◽  
Z. Sikharulidze ◽  
S. Meparishvili ◽  
M. Muradashvili ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Ralstonia Solanacearum ◽  
Erwinia Amylovora ◽  
Plant Diseases ◽  
Synchytrium Endobioticum ◽  
Monitoring And Diagnostics

Our Organization has been conducting plant diseases monitoring and diagnostics of their causal agents. We found the following quarantine pathogens: Dickeya sp., Ralstonia solanacearum, Erwinia amylovora, Pseudomonas syringae pv. actinidiae, Synchytrium endobioticum. To fix diseases on time and study their causing pathogens, is fundamental for the country safety and makes it possible not to infect a huge territory.

scholarly journals Isolation and efficacy of two bacterial strains antagonists of Erwinia amylovora and Pectobacterium carotovorum

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
M’hamed BENADA ◽  
Boualem BOUMAAZA ◽  
Sofiane BOUDALIA ◽  
Omar KHALADI
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Bacterial Species ◽  
Crop Protection ◽  
Soft Rot ◽  
Causal Agent ◽  
Plant Diseases ◽  
Ecological Niches ◽  
Pectobacterium Carotovorum ◽  
Bacterial Strains

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.

scholarly journals Resistance and Susceptibility of Arabidopsis thaliana to Bacterial Wilt Caused by Ralstonia solanacearum

1998 ◽  
Vol 88 (4) ◽  
pp. 330-334 ◽  
Author(s):  
Chang-Hsien Yang ◽  
Gan-Der Ho
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Bacterial Colonization ◽  
Plant Diseases ◽  
Infection Site ◽  
Bacterial Isolation ◽  
Tomato Plants ◽  
Different Strains ◽  
Growth Of Bacteria

Tomato bacterial wilt caused by Ralstonia solanacearum is a model system for studying plant-bacterial interactions, because it is genetically one of the best characterized plant diseases. We demonstrate here that four different strains of R. solanacearum, two from radishes (Rd4 and Rd15) and two from tomato (Ps21 and Ps95), can infect 27 different ecotypes of Arabidopsis thaliana, causing different responses. All ecotypes tested were highly susceptible to strain Rd15, which caused symptoms similar to those observed in tomato plants. For example, leaf drooping and discoloration developed just 3 days after inoculation, and plants completely wilted within 1 week. Strains Rd4 and Ps95 were less infectious than Rd15. With these two strains, a variety of disease responses were observed among different ecotypes at 2 weeks after inoculation; both susceptible and resistant ecotypes of A. thaliana were identified. Ps21 was the least infectious of the four strains and caused almost no symptoms in any of the ecotypes of Arabidopsis tested. Direct bacterial isolation and plant skeleton hybridization analysis from infected plants indicated that bacterial colonization was correlated with the severity of symptoms. Growth of bacteria was limited to the infection site in resistant plants, whereas the bacteria spread throughout susceptible plants by 1 week after inoculation.

scholarly journals Effectiveness of Dunaliella salina Extracts against Bacillus subtilis and Bacterial Plant Pathogens

Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 613
Author(s):  
Alfredo Ambrico ◽  
Mario Trupo ◽  
Rosaria Magarelli ◽  
Roberto Balducchi ◽  
Angelo Ferraro ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Pseudomonas Syringae ◽  
Dunaliella Salina ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Economic Losses ◽  
Tomato Plants ◽  
Hexane Extracts

Several bacteria pathogens are responsible for plant diseases causing significant economic losses. The antibacterial activity of Dunaliella salina microalgae extracts were investigated in vitro and in vivo. First, biomass composition was chemically characterized and subjected to extraction using polar/non-polar solvents. The highest extraction yield was obtained using chloroform:methanol (1:1 v/v) equal to 170 mg g−1 followed by ethanol (88 mg g−1) and hexane (61 mg g−1). In vitro examination of hexane extracts of Dunaliella salina demonstrated antibacterial activity against all tested bacteria. The hexane extract showed the highest amount of β-carotene with respect to the others, so it was selected for subsequent analyses. In vivo studies were also carried out using hexane extracts of D. salina against Pseudomonas syringae pv. tomato and Pectobacterium carotovorum subsp. carotovorum on young tomato plants and fruits of tomato and zucchini, respectively. The treated young tomato plants exhibited a reduction of 65.7% incidence and 77.0% severity of bacterial speck spot disease. Similarly, a reduction of soft rot symptoms was observed in treated tomato and zucchini fruits with a disease incidence of 5.3% and 12.6% with respect to 90.6% and 100%, respectively, for the positive control.

scholarly journals Homeopathic Treatment ofArabidopsis thalianaPlants Infected withPseudomonas syringae

2009 ◽  
Vol 9 ◽  
pp. 320-330 ◽  
Author(s):  
Devika Shah-Rossi ◽  
Peter Heusser ◽  
Stephan Baumgartner
Keyword(s):  
Pseudomonas Syringae ◽  
Infection Rate ◽  
Effect Size ◽  
Ecological Impact ◽  
Basic Research ◽  
Plant Diseases ◽  
Model Systems ◽  
Medium Effect ◽  
Widespread Application ◽  
Homeopathic Treatment

Homeopathic basic research is still in the screening phase to identify promising model systems that are adapted to the needs and peculiarities of homeopathic medicine and pharmacy. We investigated the potential of a common plant-pathogen system, Arabidopsis thaliana infected with the virulent bacteria Pseudomonas syringae, regarding its response towards a homeopathic treatment. A. thaliana plants were treated with homeopathic preparations before and after infection. Outcome measure was the number of P. syringae bacteria in the leaves of A. thaliana, assessed in randomized and blinded experiments. After a screening of 30 homeopathic preparations, we investigated the effect of Carbo vegetabilis 30x, Magnesium phosphoricum 30x, Nosode 30x, Biplantol (a homeopathic complex remedy), and Biplantol 30x on the infection rate in five or six independent experiments in total. The screening yielded significant effects for four out of 30 tested preparations. In the repeated experimental series, only the homeopathic complex remedy Biplantol induced a significant reduction of the infection rate (p = 0.01; effect size, d = 0.38). None of the other four repeatedly tested preparations (Carbo vegetabilis 30x, Magnesium phosphoricum 30x, Nosode 30x, Biplantol 30x) yielded significant effects in the overall evaluation. This phytopathological model yielded a small to medium effect size and thus might be of interest for homeopathic basic research after further improvement. Compared to Bion (a common SAR inducer used as positive control), the magnitude of the treatment effect of Biplantol was about 50%. Thus, homeopathic formulations might have a potential for the treatment of plant diseases after further optimization. However, the ecological impact should be investigated more closely before widespread application.

scholarly journals Comprehensive Identification of PTI Suppressors in Type III Effector Repertoire Reveals that Ralstonia solanacearum Activates Jasmonate Signaling at Two Different Steps

2019 ◽  
Vol 20 (23) ◽  
pp. 5992 ◽  
Author(s):  
Masahito Nakano ◽  
Takafumi Mukaihara
Keyword(s):  
Pseudomonas Syringae ◽  
Cysteine Protease ◽  
Ralstonia Solanacearum ◽  
Acid Synthesis ◽  
Defense Responses ◽  
Dependent Manner ◽  
Jaz Proteins ◽  
Ros Burst ◽  
Ja Signaling ◽  
Activity Dependent

Ralstonia solanacearum is the causative agent of bacterial wilt in many plants. To identify R. solanacearum effectors that suppress pattern-triggered immunity (PTI) in plants, we transiently expressed R. solanacearum RS1000 effectors in Nicotiana benthamiana leaves and evaluated their ability to suppress the production of reactive oxygen species (ROS) triggered by flg22. Out of the 61 effectors tested, 11 strongly and five moderately suppressed the flg22-triggered ROS burst. Among them, RipE1 shared homology with the Pseudomonas syringae cysteine protease effector HopX1. By yeast two-hybrid screening, we identified jasmonate-ZIM-domain (JAZ) proteins, which are transcriptional repressors of the jasmonic acid (JA) signaling pathway in plants, as RipE1 interactors. RipE1 promoted the degradation of JAZ repressors and induced the expressions of JA-responsive genes in a cysteine–protease-activity-dependent manner. Simultaneously, RipE1, similarly to the previously identified JA-producing effector RipAL, decreased the expression level of the salicylic acid synthesis gene that is required for the defense responses against R. solanacearum. The undecuple mutant that lacks 11 effectors with a strong PTI suppression activity showed reduced growth of R. solanacearum in Nicotiana plants. These results indicate that R. solanacearum subverts plant PTI responses using multiple effectors and manipulates JA signaling at two different steps to promote infection.

scholarly journals Nitrogen Limitation Alters the Response of Specific Genes to Biotic Stress

2018 ◽  
Vol 19 (11) ◽  
pp. 3364 ◽  
Author(s):  
Mahsa Farjad ◽  
Martine Rigault ◽  
Stéphanie Pateyron ◽  
Marie-Laure Martin-Magniette ◽  
Anne Krapp ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Biotic Stress ◽  
Erwinia Amylovora ◽  
Specific Response ◽  
Transcriptomic Data ◽  
Qrt Pcr ◽  
N Limitation ◽  
Combined Stresses ◽  
Response To Stress ◽  
Transcriptomic Responses

In their natural environment, plants are generally confronted with multiple co-occurring stresses. However, the interaction between stresses is not well known and transcriptomic data in response to combined stresses remain scarce. This study aims at characterizing the interaction between transcriptomic responses to biotic stress and nitrogen (N) limitation. Plants were grown in low or full N, infected or not with Erwinia amylovora (Ea) and plant gene expression was analyzed through microarray and qRT-PCR. Most Ea-responsive genes had the same profile (induced/repressed) in response to Ea in low and full N. In response to stress combination, one third of modulated transcripts responded in a manner that could not be deduced from their response to each individual stress. Many defense-related genes showed a prioritization of their response to biotic stress over their response to N limitation, which was also observed using Pseudomonas syringae as a second pathosystem. Our results indicate an interaction between transcriptomic responses to N and biotic stress. A small fraction of transcripts was prioritized between antagonistic responses, reflecting a preservation of the plant defense program under N limitation. Furthermore, this interaction also led to a complex and specific response in terms of metabolism and cellular homeostasis-associated genes.

scholarly journals The awr Gene Family Encodes a Novel Class of Ralstonia solanacearum Type III Effectors Displaying Virulence and Avirulence Activities

2012 ◽  
Vol 25 (7) ◽  
pp. 941-953 ◽  
Author(s):  
Montserrat Solé ◽  
Crina Popa ◽  
Oriane Mith ◽  
Kee Hoon Sohn ◽  
Jonathan D. G. Jones ◽  
...  
Keyword(s):  
Gene Family ◽  
Pseudomonas Syringae ◽  
Ralstonia Solanacearum ◽  
Tomato Dc3000 ◽  
Type Iii Effectors ◽  
Type Iii ◽  
New Gene ◽  
Transient Overexpression ◽  
Effector Recognition

We present here the characterization of a new gene family, awr, found in all sequenced Ralstonia solanacearum strains and in other bacterial pathogens. We demonstrate that the five paralogues in strain GMI1000 encode type III-secreted effectors and that deletion of all awr genes severely impairs its capacity to multiply in natural host plants. Complementation studies show that the AWR (alanine-tryptophan-arginine tryad) effectors display some functional redundancy, although AWR2 is the major contributor to virulence. In contrast, the strain devoid of all awr genes (Δawr1-5) exhibits enhanced pathogenicity on Arabidopsis plants. A gain-of-function approach expressing AWR in Pseudomonas syringae pv. tomato DC3000 proves that this is likely due to effector recognition, because AWR5 and AWR4 restrict growth of this bacterium in Arabidopsis. Transient overexpression of AWR in nonhost tobacco species caused macroscopic cell death to varying extents, which, in the case of AWR5, shows characteristics of a typical hypersensitive response. Our work demonstrates that AWR, which show no similarity to any protein with known function, can specify either virulence or avirulence in the interaction of R. solanacearum with its plant hosts.

scholarly journals Identification of Erwinia amylovora Genes Induced during Infection of Immature Pear Tissue

2005 ◽  
Vol 187 (23) ◽  
pp. 8088-8103 ◽  
Author(s):  
Youfu Zhao ◽  
Sara E. Blumer ◽  
George W. Sundin
Keyword(s):  
Pseudomonas Syringae ◽  
Erwinia Amylovora ◽  
Sequence Similarity ◽  
Type Ii Secretion ◽  
Knockout Mutant ◽  
Technology System ◽  
Microbe Interactions ◽  
Host Microbe Interactions ◽  
Blight Disease

ABSTRACT The enterobacterium Erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. In this study, we used a modified in vivo expression technology system to identify E. amylovora genes that are activated during infection of immature pear tissue, a process that requires the major pathogenicity factors of this organism. We identified 394 unique pear fruit-induced (pfi) genes on the basis of sequence similarity to known genes and separated them into nine putative function groups including host-microbe interactions (3.8%), stress response (5.3%), regulation (11.9%), cell surface (8.9%), transport (13.5%), mobile elements (1.0%), metabolism (20.3%), nutrient acquisition and synthesis (15.5%), and unknown or hypothetical proteins (19.8%). Known virulence genes, including hrp/hrc components of the type III secretion system, the major effector gene dspE, type II secretion, levansucrase (lsc), and regulators of levansucrase and amylovoran biosynthesis, were upregulated during pear tissue infection. Known virulence factors previously identified in E. (Pectobacterium) carotovora and Pseudomonas syringae were identified for the first time in E. amylovora and included HecA hemagglutinin family adhesion, Peh polygalacturonase, new effector HopPtoCEA, and membrane-bound lytic murein transglycosylase MltEEA. An insertional mutation within hopPtoC EA did not result in reduced virulence; however, an mltE EA knockout mutant was reduced in virulence and growth in immature pears. This study suggests that E. amylovora utilizes a variety of strategies during plant infection and to overcome the stressful and poor nutritional environment of its plant hosts.

scholarly journals Eco-Friendly Cinnamaldehyde Based Emulsion for Phytopathogenic Bacterial Growth Inhibitor

2020 ◽  
pp. 1-12
Author(s):  
Tahany G. M. Mohammed ◽  
A. F. Abd El- Rahman
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Ralstonia Solanacearum ◽  
Erwinia Amylovora ◽  
Plant Protection ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agricultural Crop ◽  
Water Emulsion ◽  
Phytopathogenic Bacteria

The formulation plays an essential role in achieving the successful delivery and biological activity of any plant protection products. This study aimed to develop a cinnamaldehyde water-based formulation (oil-in-water emulsion) via a high-shear stirring emulsification method. Cinnamaldehyde emulsion was successfully prepared and characterized using different physicochemical parameters (emulsion stability, persistent foaming, accelerated storage at 54°C for 2 weeks, and stability at 0°Cfor one week, as well as pH, surface tension, flash point, viscosity, and particle size distribution). Also, the antibacterial activity was verified in vitro against some important phytopathogenic bacteria; Erwinia amylovora, Pectobacterium aroidearum, Pseudomonas aeruginosa, and Ralstonia solanacearum using well diffusion method. In addition, the minimum inhibition concentration (MIC) was determined by the twofold dilution method. The results revealed that the prepared formulation showed good storage stability, exhibited non-Newtonian shear-thinning behavior and promising antibacterial activity. The inhibition zones against the tested phytopathogenic bacteria were ranged from 10.3 mm to 52.0 mm. MICs of the prepared formulation were 15.63, 31.25, 62.5, and 15.63 μl/ml against Erwinia amylovora, Pectobacterium aroidearum, Pseudomonas aeruginosa and Ralstonia solanacearum, respectively. Our results provide an environmentally friendly formulation with promising activity to control the agricultural crop disease.

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