scholarly journals Potential Control of Potato Soft Rot Disease by the Obligate Predators Bdellovibrio and Like Organisms

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
Daniel Youdkes ◽  
Yael Helman ◽  
Saul Burdman ◽  
Ofra Matan ◽  
Edouard Jurkevitch
Keyword(s):  
Plant Pathogens ◽  
Soft Rot ◽  
Plant Diseases ◽  
Predator Population ◽  
Bacterial Soft Rot ◽  
Population Parameters ◽  
Live Prey ◽  
Content Type ◽  
Wide Range

ABSTRACT Bacterial soft rot diseases caused by Pectobacterium spp. and Dickeya spp. affect a wide range of crops, including potatoes, a major food crop. As of today, farmers mostly rely on sanitary practices, water management, and plant nutrition for control. We tested the bacterial predators Bdellovibrio and like organisms (BALOs) to control potato soft rot. BALOs are small, motile predatory bacteria found in terrestrial and aquatic environments. They prey on a wide range of Gram-negative bacteria, including animal and plant pathogens. To this end, BALO strains HD100, 109J, and a ΔmerRNA derivative of HD100 were shown to efficiently prey on various rot-causing strains of Pectobacterium and Dickeya solani. BALO control of maceration caused by a highly virulent strain of Pectobacterium carotovorum subsp. brasilense was then tested in situ using a potato slice assay. All BALO strains were highly effective at reducing disease, up to complete prevention. Effectivity was concentration dependent, and BALOs applied before P. carotovorum subsp. brasilense inoculation performed significantly better than those applied after the disease-causing agent, maybe due to in situ consumption of glucose by the prey, as glucose metabolism by live prey bacteria was shown to prevent predation. Dead predators and the supernatant of BALO cultures did not significantly prevent maceration, indicating that predation was the major mechanism for the prevention of the disease. Finally, plastic resistance to predation was affected by prey and predator population parameters, suggesting that population dynamics affect prey response to predation. IMPORTANCE Bacterial soft rot diseases caused by Pectobacterium spp. and Dickeya spp. are among the most important plant diseases caused by bacteria. Among other crops, they inflict large-scale damage to potatoes. As of today, farmers have few options to control them. The bacteria Bdellovibrio and like organisms (BALOs) are obligate predators of bacteria. We tested their potential to prey on Pectobacterium spp. and Dickeya spp. and to protect potato. We show that different BALOs can prey on soft rot-causing bacteria and prevent their growth in situ, precluding tissue maceration. Dead predators and the supernatant of BALO cultures did not significantly prevent maceration, showing that the effect is due to predation. Soft rot control by the predators was concentration dependent and was higher when the predator was inoculated ahead of the prey. As residual prey remained, we investigated what determines their level and found that initial prey and predator population parameters affect prey response to predation.

scholarly journals Silver Nanoparticles Complexed with Bovine Submaxillary Mucin Possess Strong Antibacterial Activity and Protect against Seedling Infection

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
Daria Makarovsky ◽  
Ludmila Fadeev ◽  
Bolaji Babajide Salam ◽  
Einat Zelinger ◽  
Ofra Matan ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Ag Nps ◽  
Simple Method ◽  
Content Type ◽  
Low Concentrations ◽  
Wide Range ◽  
Bovine Submaxillary Mucin

ABSTRACT A simple method for the synthesis of nanoparticles (NPs) of silver (Ag) in a matrix of bovine submaxillary mucin (BSM) was reported previously by some of the authors of this study. Based on mucin characteristics such as long-lasting stability, water solubility, and surfactant and adhesive characteristics, we hypothesized that these compounds, named BSM-Ag NPs, may possess favorable properties as potent antimicrobial agents. The goal of this study was to assess whether BSM-Ag NPs possess antibacterial activity, focusing on important plant-pathogenic bacterial strains representing both Gram-negative ( Acidovorax and Xanthomonas ) and Gram-positive ( Clavibacter ) genera. Growth inhibition and bactericidal assays, as well as electron microscopic observations, demonstrate that BSM-Ag NPs, at relatively low concentrations of silver, exert strong antimicrobial effects. Moreover, we show that treatment of melon seeds with BSM-Ag NPs effectively prevents seed-to-seedling transmission of Acidovorax citrulli , one of the most threatening pathogens of cucurbit production worldwide. Overall, our findings demonstrate strong antimicrobial activity of BSM-Ag NPs and their potential application for reducing the spread and establishment of devastating bacterial plant diseases in agriculture. IMPORTANCE Bacterial plant diseases challenge agricultural production, and the means available to manage them are limited. Importantly, many plant-pathogenic bacteria have the ability to colonize seeds, and seed-to-seedling transmission is a critical route by which bacterial plant diseases spread to new regions and countries. The significance of our study resides in the following aspects: (i) the simplicity of the method of BSM-Ag NP synthesis, (ii) the advantageous chemical properties of BSM-Ag NPs, (iii) the strong antibacterial activity of BSM-Ag NPs at relatively low concentrations of silver, and (iv) the fact that, in contrast to most studies on the effects of metal NPs on plant pathogens, the proof of concept for the novel compound is supported by in planta assays. Application of this technology is not limited to agriculture; BSM-Ag NPs potentially could be exploited as a potent antimicrobial agent in a wide range of industrial areas, including medicine, veterinary medicine, cosmetics, textiles, and household products.

scholarly journals Microbial antagonists against plant pathogens in Iran: A review

2020 ◽  
Vol 5 (1) ◽  
pp. 404-440 ◽  
Author(s):  
Mehrdad Alizadeh ◽  
Yalda Vasebi ◽  
Naser Safaie
Keyword(s):  
Biological Control ◽  
Chemical Control ◽  
Plant Disease ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Agricultural Products ◽  
Control Measures ◽  
Wide Range ◽  
Plant Disease Management ◽  
Published Research

AbstractThe purpose of this article was to give a comprehensive review of the published research works on biological control of different fungal, bacterial, and nematode plant diseases in Iran from 1992 to 2018. Plant pathogens cause economical loss in many agricultural products in Iran. In an attempt to prevent these serious losses, chemical control measures have usually been applied to reduce diseases in farms, gardens, and greenhouses. In recent decades, using the biological control against plant diseases has been considered as a beneficial and alternative method to chemical control due to its potential in integrated plant disease management as well as the increasing yield in an eco-friendly manner. Based on the reported studies, various species of Trichoderma, Pseudomonas, and Bacillus were the most common biocontrol agents with the ability to control the wide range of plant pathogens in Iran from lab to the greenhouse and field conditions.

scholarly journals Complete Genome Sequence of Dickeya dadantii subsp. dieffenbachiae Strain S3-1, Isolated from a White-Flowered Calla Lily in Taiwan

2021 ◽  
Vol 10 (37) ◽  
Author(s):  
Yung-An Lee ◽  
Kuan-Pei Chen
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Soft Rot ◽  
Erwinia Chrysanthemi ◽  
Bacterial Soft Rot ◽  
Plant Host ◽  
Dickeya Dadantii ◽  
Content Type ◽  
Calla Lily

Erwinia chrysanthemi S3-1 is a bacterial soft rot pathogen of the white-flowered calla lily. The complete genome sequence of the strain was determined and used to reclassify the strain as Dickeya dadantii subsp. dieffenbachiae . The sequence will be useful to study plant host-driven speciation in strains of D. dadantii .

scholarly journals Screening, Identification and Efficacy Evaluation of Antagonistic Bacteria for Biocontrol of Soft Rot Disease Caused by Dickeya zeae

2020 ◽  
Vol 8 (5) ◽  
pp. 697 ◽  
Author(s):  
Jieling Li ◽  
Ming Hu ◽  
Yang Xue ◽  
Xia Chen ◽  
Guangtao Lu ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Prevention And Control ◽  
Pathogenic Bacteria ◽  
Soft Rot ◽  
Antagonistic Bacteria ◽  
Bacterial Soft Rot ◽  
Soft Rot Disease ◽  
Wide Range ◽  
Rot Disease ◽  
And Control

Dickeya zeae is the causal agent of bacterial soft rot disease, with a wide range of hosts all over the world. At present, chemical agents, especially agricultural antibiotics, are commonly used in the prevention and control of bacterial soft rot, causing the emergence of resistant pathogens and therefore increasing the difficulty of disease prevention and control. This study aims to provide a safer and more effective biocontrol method for soft rot disease caused by D. zeae. The spot-on-lawn assay was used to screen antagonistic bacteria, and three strains including SC3, SC11 and 3-10 revealed strong antagonistic effects and were identified as Pseudomonas fluorescens, P. parafulva and Bacillus velezensis, respectively, using multi-locus sequence analysis (MLSA) based on the sequences of 16S rRNA and other housekeeping genes. In vitro antimicrobial activity showed that two Pseudomonas strains SC3 and SC11 were only antagonistic to some pathogenic bacteria, while strain 3-10 had broad-spectrum antimicrobial activity on both pathogenic bacteria and fungi. Evaluation of control efficacy in greenhouse trials showed that they all restrained the occurrence and development of soft rot disease caused by D. zeae MS2 or EC1. Among them, strain SC3 had the most impressive biocontrol efficacy on alleviating the soft rot symptoms on both monocotyledonous and dicotyledonous hosts, and strain 3-10 additionally reduced the occurrence of banana wilt disease caused by Fusarium oxysporum f. sp. cubensis. This is the first report of P. fluorescens, P. parafulva and B. velezensis as potential bio-reagents on controlling soft rot disease caused by D. zeae.

scholarly journals Emergence of Bacterial Soft Rot in Cucumber Caused by Pectobacterium carotovorum subsp. brasiliense in China

Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 279-287 ◽  
Author(s):  
Xianglong Meng ◽  
Ali Chai ◽  
Yanxia Shi ◽  
Xuewen Xie ◽  
Zhanhong Ma ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Soft Rot ◽  
Economic Losses ◽  
Pectobacterium Carotovorum ◽  
Bacterial Soft Rot ◽  
Bacterial Strains ◽  
Phenotypic Properties ◽  
Gene Sequence Analysis ◽  
Wide Range ◽  
Carotovorum Subsp

During 2014 to 2015, a devastating bacterial soft rot on cucumber stems and leaves occurred in Shandong, Shanxi, Hebei, Henan, and Liaoning provinces of China, resulting in serious economic losses for cucumber production. The gummosis emerged on the surface of leaves, stems, petioles, and fruit of cucumber. The basal stem color was dark brown and the stem base turned to wet rot. Yellow spots and wet rot emerged at the edge of the infected cucumber leaves and gradually infected the leaf centers. In total, 45 bacterial strains were isolated from the infected tissues. On the basis of phenotypic properties of morphology, physiology, biochemistry, and 16S ribosomal RNA gene sequence analysis, the pathogen was identified as Pectobacterium carotovorum. Multilocus sequence analysis confirmed that the isolates were P. carotovorum subsp. brasiliense, and the pathogens fell in clade II. The pathogenicity of isolated bacteria strains was confirmed. The strains reisolated were the same as the original. The host range test confirmed that strains had a wide range of hosts. As far as we know, this is the first report of cucumber stem soft rot caused by P. carotovorum subsp. brasiliense in China as well as in the world, which has a significant economic impact on cucumber production.

scholarly journals “Candidatus Finniella” (Rickettsiales, Alphaproteobacteria), Novel Endosymbionts of Viridiraptorid Amoeboflagellates (Cercozoa, Rhizaria)

2015 ◽  
Vol 82 (2) ◽  
pp. 659-670 ◽  
Author(s):  
Sebastian Hess ◽  
Andreas Suthaus ◽  
Michael Melkonian
Keyword(s):  
Rrna Gene ◽  
The Novel ◽  
Single Nucleotide ◽  
Content Type ◽  
Obligate Intracellular ◽  
Wide Range ◽  
Candidate Species ◽  
Novel Bacteria ◽  
Obligate Intracellular Bacteria

ABSTRACTTheRickettsiales(Alphaproteobacteria) are obligate intracellular bacteria that colonize a wide range of eukaryotic hosts, including diverse metazoa and protists. Here, we characterize rickettsial endosymbionts discovered in the cytoplasm of the algivorous amoeboflagellatesViridiraptor invadensandOrciraptor agilis(Viridiraptoridae, Cercozoa, Rhizaria), supplying evidence of free-living, phagotrophic members of the Cercozoa serving as hosts forRickettsiales. According to 16S rRNA gene phylogenies, the bacteria represent two closely related but distinct genotypes within a deep-branching rickettsial clade, which contains the genera “CandidatusOdyssella,” “CandidatusParacaedibacter,” and “CandidatusCaptivus.” Using the full-cycle rRNA approach, we detected the novel bacteria in four of nine viridiraptorid strains tested. Furthermore, two specific oligonucleotide probes with a single-nucleotide-difference discriminated both bacterial genotypes by fluorescencein situhybridization (FISH). We establish the candidate species “CandidatusFinniella inopinata” (found inViridiraptor invadens) and “CandidatusFinniella lucida” (found inOrciraptor agilis) for the novel bacteria and propose a new, provisional family ofRickettsiales, “CandidatusParacaedibacteraceae.”

scholarly journals First Report of Bacterial Soft Rot of Potato Caused by Pectobacterium carotovorum subsp. carotovorum in Guangdong Province of China

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1819-1819 ◽  
Author(s):  
J. X. Zhang ◽  
B. R. Lin ◽  
H. F. Shen ◽  
X. M. Pu ◽  
Z. N. Chen ◽  
...  
Keyword(s):  
Guangdong Province ◽  
Housekeeping Genes ◽  
Soft Rot ◽  
Bacterial Suspension ◽  
Pectobacterium Carotovorum ◽  
Bacterial Soft Rot ◽  
First Report ◽  
Wide Range ◽  
Carotovorum Subsp ◽  
Agar Media

Potato (Solanum tuberosum L.) is a major crop in China, with 80.0 million tons being produced in 2010 on 3.3 million ha. Pectobacterium carotovorum subsp. carotovorum Jones 1901; Hauben et al. 1999 causes soft rot worldwide on a wide range of hosts including potato, carrot, and cabbage. During spring 2010, a soft rot with a foul smell was noted in stored potato tubers of different cultivars in the Guangdong Province. Symptoms on tubers appeared as tan, water-soaked areas with watery ooze. The rotted tissues were white to cream colored. Stems of infected plants with typical inky black symptoms could also be found in the fields prior to harvest. Three different potato fields were surveyed, and 13% of the plants had the symptoms. Twenty-seven samples (three symptomatic tubers per sample) were collected. Bacteria were successfully isolated from all diseased tissues on nutrient agar media supplemented with 5% sucrose and incubated at 26 ± 1°C for 36 h. After purification on tripticase soy agar media, four typical strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) were identified using the following deterministic tests: gram-negative rods, oxidase negative, facultatively anaerobic, able to degrade pectate, sensitive to erythromycin, negative for phosphatase, unable to produce acid from α-methyl-glucoside, and produced acid from trehalose. Biolog analysis (Ver 4.20.05, Hayward, CA) identified the strains as P. carotovorum subsp. carotovorum (SIM 0.808, 0.774, 0.782, and 0.786, respectively). The identity of strains 7-3-1 (GenBank Accession No. JX258132), 7-3-2 (JX258133), and 8-3-1 (JX196705) was confirmed by 16S rRNA gene sequencing (4), since they had 99% sequence identity with other P. carotovorum subsp. carotovorum strains (GenBank Accession Nos. JF926744 and JF926758) using BLASTn. Further genetic analysis of strain 8-3-1 was performed targeting informative housekeeping genes, i.e., acnA (GenBank Accession No. JX196704), gabA (JX196706), icdA (JX196707), mdh (JX196708), mtlD (JX196709), pgi (JX196710), and proA (JX196711) (2). These sequences from strain 8-3-1 were 99 to 100%, homologous to sequences of multiple strains of P. carotovorum subsp. carotovorum. Therefore, strain 8-3-1 grouped with P. carotovorum subsp. carotovorum on the phylogenetic trees (neighbor-joining method, 1,000 bootstrap values) of seven concatenated housekeeping genes when compared with 60 other strains, including Pectobacterium spp. and Dickeya spp. (3). Pathogenicity of four strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) was evaluated by depositing a bacterial suspension (106 CFU/ml) on the potato slices of cultivar ‘Favorita’ and incubating at 30 ± 1°C. Slices inoculated with just water served as non-inoculated checks. The strains caused soft rot within 72 h and the checks had no rot. Bacteria were reisolated from the slices and were shown to be identical to the original strains based on morphological, cultural, and biochemical tests. Although this pathogen has already been reported in northern China (1), to our knowledge, this is the first report of P. carotovorum subsp. carotovorum causing bacterial soft rot of potato in Guangdong Province of China. References: (1) Y. X. Fei et al. J. Hexi Univ. 26:51, 2010.(2) B. Ma et al. Phytobacteriology 97:1150, 2007. (3) S. Nabhan et al. Plant Pathol. 61:498, 2012. (4) W. G. Weisbury et al. J. Bacteriol. 173:697, 1991.

scholarly journals De Novo Design of Antimicrobial Peptides With a Special Charge Pattern and Their Application in Combating Plant Pathogens

2021 ◽  
Vol 12 ◽  
Author(s):  
Eric H. -L. Chen ◽  
Cheng-Wei Weng ◽  
Yi-Min Li ◽  
Ming-Chin Wu ◽  
Chien-Chih Yang ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Plant Pathogens ◽  
De Novo ◽  
Plant Protection ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Plant Diseases ◽  
Basic Residue ◽  
Wide Range

Plant diseases are important issues in agriculture, and the development of effective and environment-friendly means of disease control is crucial and highly desired. Antimicrobial peptides (AMPs) are known as potential alternatives to chemical pesticides because of their potent broad-spectrum antimicrobial activity and because they have no risk, or have only a low risk, of developing chemical-resistant pathogens. In this study, we designed a series of amphipathic helical peptides with different spatial distributions of positive charges and found that the peptides that had a special sequence pattern “BBHBBHHBBH” (“B” for basic residue and “H” for hydrophobic residue) displayed excellent bactericidal and fungicidal activities in a wide range of economically important plant pathogens. The peptides with higher helical propensity had lower antimicrobial activity. When we modified the peptides with a long acyl chain at their N-terminus, their plant protection effect improved. Our application of the fatty acyl-modified peptides on the leaves of tomato and Arabidopsis plants lessened the infection caused by Pectobacterium carotovorum subsp. carotovorum and Botrytis cinerea. Our study provides important insights on the development of more potent novel AMPs for plant protection.

scholarly journals Essential Oils as Potential Alternative Biocontrol Products against Plant Pathogens and Weeds: A Review

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 365 ◽  
Author(s):  
Robin Raveau ◽  
Joël Fontaine ◽  
Anissa Lounès-Hadj Sahraoui
Keyword(s):  
Essential Oils ◽  
Plant Pathogens ◽  
Crop Yields ◽  
Biological Activities ◽  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
Plant Diseases ◽  
Present Review ◽  
Traditional Medicines ◽  
Wide Range

Naturally produced by aromatic plants, essential oils (EO) contain a wide range of volatile molecules, including mostly secondary metabolites, which possess several biological activities. Essential oils properties such as antioxidant, antimicrobial and anti-inflammatory activities are known for a long time and hence widely used in traditional medicines, cosmetics and food industries. However, despite their effects against many phytopathogenic fungi, oomycetes and bacteria as well as weeds, their use in agriculture remains surprisingly scarce. The purpose of the present review is to gather and discuss up-to-date biological activities of EO against weeds, plant pathogenic fungi, oomycetes and bacteria, reported in the scientific literature. Innovative methods, potentially valuable to improve the efficiency and reliability of EO, have been investigated. In particular, their use towards a more sustainable agriculture has been discussed, aiming at encouraging the use of alternative products to substitute synthetic pesticides to control weeds and plant diseases, without significantly affecting crop yields. An overview of the market and the recent advances on the regulation of these products as well as future challenges to promote their development and wider use in disease management programs is described. Because of several recent reviews on EO insecticidal properties, this topic is not covered in the present review.

scholarly journals Expression of a Peptidoglycan Hydrolase from Lytic Bacteriophages Atu_ph02 and Atu_ph03 Triggers Lysis of Agrobacterium tumefaciens

2017 ◽  
Vol 83 (23) ◽  
Author(s):  
Hedieh Attai ◽  
Jeanette Rimbey ◽  
George P. Smith ◽  
Pamela J. B. Brown
Keyword(s):  
Cell Division ◽  
Agrobacterium Tumefaciens ◽  
Plant Pathogens ◽  
Transmembrane Domain ◽  
Cell Lysis ◽  
Tumor Formation ◽  
Plant Diseases ◽  
Bacterial Cells ◽  
Content Type ◽  
Endogenous Expression

ABSTRACT To provide food security, innovative approaches to preventing plant disease are currently being explored. Here, we demonstrate that lytic bacteriophages and phage lysis proteins are effective at triggering lysis of the phytopathogen Agrobacterium tumefaciens. Phages Atu_ph02 and Atu_ph03 were isolated from wastewater and induced lysis of C58-derived strains of A. tumefaciens. The coinoculation of A. tumefaciens with phages on potato discs limited tumor formation. The genomes of Atu_ph02 and Atu_ph03 are nearly identical and are ∼42% identical to those of T7 supercluster phages. In silico attempts to find a canonical lysis cassette were unsuccessful; however, we found a putative phage peptidoglycan hydrolase (PPH), which contains a C-terminal transmembrane domain. Remarkably, the endogenous expression of pph in the absence of additional phage genes causes a block in cell division and subsequent lysis of A. tumefaciens cells. When the presumed active site of the N-acetylmuramidase domain carries an inactivating mutation, PPH expression causes extensive cell branching due to a block in cell division but does not trigger rapid cell lysis. In contrast, the mutation of positively charged residues at the extreme C terminus of PPH causes more rapid cell lysis. Together, these results suggest that PPH causes a block in cell division and triggers cell lysis through two distinct activities. Finally, the potent killing activity of this single lysis protein can be modulated, suggesting that it could be engineered to be an effective enzybiotic. IMPORTANCE The characterization of bacteriophages such as Atu_ph02 and Atu_ph03, which infect plant pathogens such as Agrobacterium tumefaciens, may be the basis of new biocontrol strategies. First, cocktails of diverse bacteriophages could be used as a preventative measure to limit plant diseases caused by bacteria; a bacterial pathogen is unlikely to simultaneously develop resistances to multiple bacteriophage species. The specificity of bacteriophage treatment for the host is an asset in complex communities, such as in orchards where it would be detrimental to harm the symbiotic bacteria in the environment. Second, bacteriophages are potential sources of enzymes that efficiently lyse bacterial cells. These phage proteins may have a broad specificity, but since proteins do not replicate as phages do, their effect is highly localized, providing an alternative to traditional antibiotic treatments. Thus, studies of lytic bacteriophages that infect A. tumefaciens may provide insights for designing preventative strategies against bacterial pathogens.

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