First Report of Shot-hole on Flowering Cherry Caused by Burkholderia contaminans and Pseudomonas syringae pv. syringae

The shot-hole disease (SH) is one of the most common and important diseases affecting the flowering cherry (FC; Prunus × yedoensis Matsumura; ‘Somei-yoshino’) trees in South Korea every year, resulting in premature defoliation and reduced flowering in the following year. However, pathogens associated with the disease remain unknown, which has rendered disease management challenging. Here, the pathogens associated with SH, their biochemical characteristics, and their host range were elucidated. Detached leaf and in planta assays revealed that two biofilm-forming bacteria, namely Burkholderia contaminans (Bc) and Pseudomonas syringae pv. syringae (Pss), caused SH of FC trees. These pathogens were recorded for the first time as the causes of SH of FC trees in South Korea. Additionally, the two pathogens induced similar disease symptoms in several stone fruits belonging to the genus Prunus, including peach (P. persica), plum (P. salicina), and apricot (P. mume), with peach being the most susceptible. These results indicate that Bc and Pss caused SH on FC trees and presented a broad spectrum of hosts. Furthermore, Xanthomonas arboricola pv. pruni, the causative agent of leaf spot on stone fruits, incited brown spots and shot holes on FC leaves. Therefore, FC trees are susceptible to infections by various pathogenic bacteria, including Bc, Pss, and Xap. These findings will be of great importance as a reference for effective management of SH in the face of possible cross-infection between Prunus species in the future.

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Prediction and Activity of a Cationic α-Helix Antimicrobial Peptide ZM-804 from Maize

International Journal of Molecular Sciences ◽

10.3390/ijms22052643 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2643

Author(s):

Mohamed F. Hassan ◽

Abdelrahman M. Qutb ◽

Wubei Dong

Keyword(s):

Cdna Library ◽

Pseudomonas Syringae ◽

Inbred Line ◽

Mammalian Cells ◽

Laser Scanning ◽

Pathogenic Bacteria ◽

Antimicrobial Activities ◽

Confocal Laser ◽

In Planta ◽

Minimal Inhibitory Concentrations

Antimicrobial peptides (AMPs) are small molecules consisting of less than fifty residues of amino acids. Plant AMPs establish the first barrier of defense in the innate immune system in response to invading pathogens. The purpose of this study was to isolate new AMPs from the Zea mays L. inbred line B73 and investigate their antimicrobial activities and mechanisms against certain essential plant pathogenic bacteria. In silico, the Collection of Anti-Microbial Peptides (CAMPR3), a computational AMP prediction server, was used to screen a cDNA library for AMPs. A ZM-804 peptide, isolated from the Z. mays L. inbred line B73 cDNA library, was predicted as a new cationic AMP with high prediction values. ZM-804 was tested against eleven pathogens of Gram-negative and Gram-positive bacteria and exhibited high antimicrobial activities as determined by the minimal inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs). A confocal laser scanning microscope observation showed that the ZM-804 AMP targets bacterial cell membranes. SEM and TEM images revealed the disruption and damage of the cell membrane morphology of Clavibacter michiganensis subsp. michiganensis and Pseudomonas syringae pv. tomato (Pst) DC3000 caused by ZM-804. In planta, ZM-804 demonstrated antimicrobial activity and prevented the infection of tomato plants by Pst DC3000. Moreover, four virulent phytopathogenic bacteria were prevented from inducing hypersensitive response (HR) in tobacco leaves in response to low ZM-804 concentrations. ZM-804 exhibits low hemolytic activity against mouse red blood cells (RBCs) and is relatively safe for mammalian cells. In conclusion, the ZM-804 peptide has a strong antibacterial activity and provides an alternative tool for plant disease control. Additionally, the ZM-804 peptide is considered a promising candidate for human and animal drug development.

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Negative Regulation of the Hrp Type III Secretion System in Pseudomonas syringae pv. phaseolicola

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-5-0682 ◽

2010 ◽

Vol 23 (5) ◽

pp. 682-701 ◽

Cited By ~ 26

Author(s):

Inmaculada Ortiz-Martín ◽

Richard Thwaites ◽

John W. Mansfield ◽

Carmen R. Beuzón

Keyword(s):

Gene Expression ◽

Pseudomonas Syringae ◽

Type Iii Secretion ◽

Pathogenic Bacteria ◽

In Planta ◽

Secretion Systems ◽

Type Iii ◽

Type Iii Secretion Systems ◽

Bacterial Fitness

Many plant-pathogenic bacteria require type III secretion systems (T3SS) to cause disease in compatible hosts and to induce the hypersensitive response in resistant plants. T3SS gene expression is induced within the plant and responds to host and environmental factors. In Pseudomonas syringae, expression is downregulated by the Lon protease in rich medium and by HrpV under inducing conditions. HrpV acts as an anti-activator by binding HrpS. HrpG, which can also bind HrpV, has been reported to act as an anti-anti-activator. Previous studies have used mostly in vitro inducing conditions, different pathovars, and methodology. We have used single and double lon and hrpV mutants of P. syringae pv. phaseolicola 1448a, as well as strains ectopically expressing the regulators, to examine their role in coordinating expression of the T3SS. We applied real-time polymerase chain reaction to analyze gene expression both in vitro and in planta, and assessed bacterial fitness using competitive indices. Our results indicate that i) Lon downregulates expression of the hrp/hrc genes in all conditions, probably by constitutively degrading naturally unstable HrpR; ii) HrpV and HrpT downregulate expression of the hrp/hrc genes in all conditions; and iii) HrpG has an additional, HrpV-independent role, regulating expression of the hrpC operon.

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Effects of galU Mutation on Pseudomonas syringae–Plant Interactions

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-9-1184 ◽

2010 ◽

Vol 23 (9) ◽

pp. 1184-1196 ◽

Cited By ~ 15

Author(s):

Wen-Ling Deng ◽

Yuan-Chun Lin ◽

Rong-Hwa Lin ◽

Chia-Fong Wei ◽

Yi-Chiao Huang ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Type Iii Secretion ◽

Pathogenic Bacteria ◽

Capsular Polysaccharides ◽

Uridine Diphosphate ◽

Plant Interactions ◽

In Planta ◽

Animal Pathogens ◽

Diphosphate Glucose ◽

Molecular Patterns

Bacterial galU coding for a uridine diphosphate-glucose pyrophosphorylase plays an important role in carbohydrates biosynthesis, including synthesis of lipopolysaccharides (LPS), membrane-derived oligosaccharides, and capsular polysaccharides. In this study, we characterized the galU mutant of Pseudomonas syringae pv. syringae 61 (Psy61), a necrotizing plant pathogen whose pathogenicity depends on a functional type III secretion system (T3SS), and showed that the Psy61 galU mutant had reduced biofilm formation ability, was nonmotile, and had an assembled T3SS structure but failed to elicit hypersensitive response in resistant plants and necrotic lesions in susceptible plants. Moreover, the defective LPS and other pathogen-associated molecular patterns (PAMPs) on the surface of the Psy61 galU mutant were capable of inducing PAMP-triggered immunity, which severely compromised the ability of the Psy61 galU mutant to survive in planta. Our results demonstrated that the complete LPS protected plant-pathogenic bacteria from host innate immunity, similar to what was found in animal pathogens, prior to the translocation of T3S effectors and bacterial multiplication.

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Loop-mediated isothermal amplification: a rapid molecular technique for early diagnosis of Pseudomonas syringae pv. syringae of stone fruits

Journal of Genetic Engineering and Biotechnology ◽

10.1186/s43141-020-00062-6 ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

R. Goudarzi ◽

M. M. Mortazavi

Keyword(s):

Pseudomonas Syringae ◽

Pathogenic Bacteria ◽

Selective Medium ◽

Isothermal Amplification ◽

Plant Diseases ◽

Molecular Technique ◽

Specific Method ◽

Stone Fruits ◽

Serological Tests ◽

Loop Mediated Isothermal Amplification

Abstract Background Pathogenic bacteria cause significant economic damages in agriculture. The detection of such bacteria is considered as a continual interest for plant pathologists to prevent disease dissemination. Pseudomonas syringae pv. syringae is one of the most important bacterial pathogens infecting yield and quality of stone fruits throughout the world. Biochemical assays such as a LOPAT and GATTa are common methods to detect this pathogen. Serological tests and culturing on King’s B selective medium also used to isolate this bacterium. Selective media is composed of specific and effective ingredients to inhibit the growth of certain species of microbes in a mixed culture while allowing others to grow. These are used for the growth of only selected microorganisms. King’s B medium can be used as a general medium for the non-selective isolation cultivation and pigment production of Pseudomonas species from foods, cosmetic samples, plants, etc. Nevertheless, the mentioned methods are not enough accurate to differentiate the strains. On the other hand, PCR-based techniques are sensitive and efficient in detecting plant diseases. However, these techniques are not practicable for those researchers who do not have access to a thermal cycler. We have used loop-mediated isothermal amplification to couple with a target. The amplification of syrD gene using loop and bumper primers can be used to prevent disease dissemination. Results The outcome of this investigation indicated more sensitivity of LAMP in comparison to PCR. The direct addition of SYBR Gold in microtube is more sensitive than gel in both LAMP and PCR byproducts so we can eliminate gel electrophoresis, while the LAMP showed high sensitivity and high specificity in comparison to results obtained by cultivation. The described molecular test could detect Pseudomonas syringae pv. syringae type in nearly 1 h, and this is the first time that Lamp molecular detection of Pseudomonas syringae pv. syringae particularly on stone fruits is described and introduced. Conclusions The obtained data confirmed that LAMP is a fast, cheap, and high specific method for the rapid detection of Pseudomonas syringae pv. syringae to the comparison of PCR and culture.

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Inhibition of Fungal and Bacterial Plant Pathogens In Vitro and In Planta with Ultrashort Cationic Lipopeptides

Applied and Environmental Microbiology ◽

10.1128/aem.01334-07 ◽

2007 ◽

Vol 73 (20) ◽

pp. 6629-6636 ◽

Cited By ~ 68

Author(s):

Arik Makovitzki ◽

Ada Viterbo ◽

Yariv Brotman ◽

Ilan Chet ◽

Yechiel Shai

Keyword(s):

Pseudomonas Syringae ◽

Pathogenic Bacteria ◽

Plant Pathogens ◽

Antimicrobial Agents ◽

Plant Protection ◽

Microscopic Analysis ◽

Plant Diseases ◽

In Planta ◽

Global Food Security

ABSTRACT Plant diseases constitute an emerging threat to global food security. Many of the currently available antimicrobial agents for agriculture are highly toxic and nonbiodegradable and cause extended environmental pollution. Moreover, an increasing number of phytopathogens develop resistance to them. Recently, we have reported on a new family of ultrashort antimicrobial lipopeptides which are composed of only four amino acids linked to fatty acids (A. Makovitzki, D. Avrahami, and Y. Shai, Proc. Natl. Acad. Sci. USA 103:15997-16002, 2006). Here, we investigated the activities in vitro and in planta and the modes of action of these short lipopeptides against plant-pathogenic bacteria and fungi. They act rapidly, at low micromolar concentrations, on the membranes of the microorganisms via a lytic mechanism. In vitro microscopic analysis revealed wide-scale damage to the microorganism's membrane, in addition to inhibition of pathogen growth. In planta potent antifungal activity was demonstrated on cucumber fruits and leaves infected with the pathogen Botrytis cinerea as well as on corn leaves infected with Cochliobolus heterostrophus. Similarly, treatment with the lipopeptides of Arabidopsis leaves infected with the bacterial leaf pathogen Pseudomonas syringae efficiently and rapidly reduced the number of bacteria. Importantly, in contrast to what occurred with many native lipopeptides, no toxicity was observed on the plant tissues. These data suggest that the ultrashort lipopeptides could serve as native-like antimicrobial agents economically feasible for use in plant protection.

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Genome-wide identification ofPseudomonas syringaegenes required for competitive fitness during colonization of the leaf surface and apoplast

10.1101/637496 ◽

2019 ◽

Cited By ~ 1

Author(s):

Tyler C. Helmann ◽

Adam M. Deutschbauer ◽

Steven E. Lindow

Keyword(s):

Gene Expression ◽

Pseudomonas Syringae ◽

Plant Pathogen ◽

Pathogenic Bacteria ◽

Leaf Surface ◽

In Planta ◽

Competitive Fitness ◽

Genome Wide ◽

A Genome ◽

Leaf Surfaces

AbstractThe foliar plant pathogenPseudomonas syringaecan establish large epiphytic populations on leaf surfaces before infection. However, the bacterial genes that contribute to these lifestyles have not been completely defined. The fitness contributions of most genes inP. syringaepv.syringaeB728a were determined by genome-wide fitness profiling with a randomly barcoded transposon mutant library that was grown on the leaf surface and in the apoplast of the susceptible plantPhaseolus vulgaris. Genes within the functional categories of amino acid and polysaccharide (including alginate) biosynthesis contributed most to fitness both on the leaf surface (epiphytic) or in the leaf interior (apoplast), while genes in the type III secretion system and syringomycin synthesis were primarily important in the apoplast. Numerous other genes that had not been previously associated within plantagrowth were also required for maximum epiphytic or apoplastic fitness. Many hypothetical proteins and uncategorized glycosyltransferases were also required for maximum competitive fitness in and on leaves. For most genes, no relationship was seen between fitnessin plantaand either the magnitude of their expressionin plantaor degree of inductionin plantacompared toin vitroconditions measured in other studies. A lack of association of gene expression and fitness has important implications for the interpretation of transcriptional information and our broad understanding of plant-microbe interactions.Significance StatementMany plant pathogenic bacteria can extensively colonize leaf surfaces before entry and multiplication within the leaf to cause disease. While these habitats presumably require distinct adaptations, the genes required in these habitats and how they would differ was unknown. Using a genome-wide library of barcoded insertional mutants in the plant pathogenPseudomonas syringae, we ascertained the common and unique genes required to colonize these habitats. A lack of association between gene expression and contribution to fitness suggests that many genes that are highly expressed or inducedin plantaare dispensable or redundant. As a model bacterium for plant pathogenesis and colonization, our comprehensive genetic dataset allows us to better understand the traits needed for association with leaves.

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Mqo, a Tricarboxylic Acid Cycle Enzyme, Is Required for Virulence of Pseudomonas syringae pv. tomato Strain DC3000 on Arabidopsis thaliana

Journal of Bacteriology ◽

10.1128/jb.01570-08 ◽

2009 ◽

Vol 191 (9) ◽

pp. 3132-3141 ◽

Cited By ~ 19

Author(s):

Eve M. Mellgren ◽

Andrew P. Kloek ◽

Barbara N. Kunkel

Keyword(s):

Arabidopsis Thaliana ◽

Pseudomonas Syringae ◽

Virulence Factors ◽

Plant Tissue ◽

Pathogenic Bacteria ◽

Tricarboxylic Acid Cycle ◽

Tricarboxylic Acid ◽

Wild Type ◽

In Planta ◽

Acid Cycle

ABSTRACT Plant pathogenic bacteria, such as Pseudomonas syringae pv. tomato strain DC3000, the causative agent of tomato bacterial speck disease, grow to high levels in the apoplastic space between plant cells. Colonization of plant tissue requires expression of virulence factors that modify the apoplast to make it more suitable for pathogen growth or facilitate adaptation of the bacteria to the apoplastic environment. To identify new virulence factors involved in these processes, DC3000 Tn5 transposon insertion mutants with reduced virulence on Arabidopsis thaliana were identified. In one of these mutants, the Tn5 insertion disrupted the malate:quinone oxidoreductase gene (mqo), which encodes an enzyme of the tricarboxylic acid cycle. mqo mutants do not grow to wild-type levels in plant tissue at early time points during infection. Further, plants infected with mqo mutants develop significantly reduced disease symptoms, even when the growth of the mqo mutant reaches wild-type levels at late stages of infection. Mutants lacking mqo function grow more slowly in culture than wild-type bacteria when dicarboxylates are the only available carbon source. To explore whether dicarboxylates are important for growth of DC3000 in the apoplast, we disrupted the dctA1 dicarboxylate transporter gene. DC3000 mutants lacking dctA1 do not grow to wild-type levels in planta, indicating that transport and utilization of dicarboxylates are important for virulence of DC3000. Thus, mqo may be required by DC3000 to meet nutritional requirements in the apoplast and may provide insight into the mechanisms underlying the important, but poorly understood process of adaptation to the host environment.

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Engineering bacteriocin-mediated resistance against plant pathogenic bacteria in plants

10.1101/649178 ◽

2019 ◽

Cited By ~ 1

Author(s):

William M. Rooney ◽

Rhys Grinter ◽

Annapaula Correia ◽

Julian Parkhill ◽

Daniel Walker ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Pathogenic Bacteria ◽

Plant Pathogens ◽

Antimicrobial Agents ◽

Bacterial Disease ◽

In Planta ◽

Plant Pathogenic Bacteria ◽

Alternative Technologies ◽

Narrow Spectrum ◽

Industrial Farming

ABSTRACTPseudomonas syringae(Ps) and related plant pathogenic bacteria are responsible for losses in diverse crops such as tomato, kiwifruit, pepper, olive and soybean. Current solutions, involving the use of chemicals and the introduction of resistance genes, have enjoyed only limited success and may have adverse environmental impacts. Consequently, there is a pressing need to develop alternative technologies to address the problem of bacterial disease in crops. An alternative strategy is to utilise the narrow spectrum protein antibiotics (bacteriocins) used by diverse bacteria for competition against closely related species. Here, we demonstrate that active putidacin L1 (PL1) can be expressed at high levelsin plantaand expression of PL1 provides effective resistance against diverse pathovars ofPs.Furthermore, we found that strains which evolve to become insensitive to PL1; lose their O-antigen, exhibit reduced motility and are less virulent in PL1 transgenic plants. Our results provide proof-of-principle that transgene-mediated expression of a bacteriocinin plantais an effective strategy for providing disease resistance against bacterial pathogens. Genetically modified (GM) crops expressing insecticidal proteins have proved extremely successful as a strategy for pest management; expressing bacteriocins to control bacterial disease may have a similar potential. Crucially, nearly all genera of bacteria, including many plant pathogenic species, produce bacteriocins, providing an extensive source of these antimicrobial agents.SIGNIFICANCEWith the global population to surpass 9 billion by 2050 there is a huge demand to make industrial farming as efficient as possible. A disadvantage of industrial farming is the lack of genetic diversity within crop monocultures, which make them highly susceptible to diseases caused by plant pathogenic bacteria likePseudomonas syringae. Bacteriocins are narrow spectrum protein antibiotics which are produced by all major bacterial lineages. Their main purpose is to eliminate competitor strains to establish dominance within a niche. By arming plants with bacteriocins we can increase the genetic toolbox used to engineer crops to be resistant to specific bacterial plant pathogens.

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THE ACTIVITY OF ESSENTIAL OILS OBTAINED FROM SPECIES AND INTERSPECIES HYBRIDS OF THE Mentha GENUS AGAINST SELECTED PLANT PATHOGENIC BACTERIA

Acta Scientiarum Polonorum Hortorum Cultus ◽

10.24326/asphc.2018.6.17 ◽

2018 ◽

Vol 17 (6) ◽

pp. 167-174 ◽

Cited By ~ 1

Author(s):

Małgorzata Schollenberger ◽

Tomasz M. Staniek ◽

Elżbieta Paduch-Cichal ◽

Beata Dasiewicz ◽

Agnieszka Gadomska-Gajadhur ◽

...

Keyword(s):

Essential Oils ◽

Pseudomonas Syringae ◽

Pathogenic Bacteria ◽

Antimicrobial Effect ◽

Mentha Piperita ◽

Mentha Spicata ◽

Plant Essential Oils ◽

Plant Pathogenic Bacteria ◽

Interspecies Hybrids

Plant essential oils of six aromatic herb species and interspecies hybrids of the family Lamiaceae – chocolate mint (Mentha piperita × ‘Chocolate’), pineapple mint (Mentha suaveolens ‘Variegata’), apple mint (Mentha × rotundifolia), spearmint (Mentha spicata), orange mint (Mentha × piperita ‘Granada’) and strawberry mint (Mentha × villosa ‘Strawberry’) – were investigated for antimicrobial effects against plant pathogenic bacteria: Agrobacterium tumefaciens, Pseudomonas syringae pv. syringae and Xanthomonas arboricola pv. corylina. The screening was carried out in vitro on agar plates filled with the target organism. All essential oils screened exhibited a higher level of antibacterial activity against A. tumefaciens and X. arboricola pv. corylina than streptomycin used as a standard in all tests. The antimicrobial effect of streptomycin and five mint oils was at the same level for P. syringae pv. syringae. There were no significant differences in the influence of the chocolate mint oil on the growth inhibition of all bacteria tested. Plant essential oils from pineapple mint, apple mint, spearmint and strawberry mint showed the weakest antimicrobial activity against P. syringae pv. syringae and the strongest towards A. tumefaciens and X. arboricola pv. corylina. The essential oils from strawberry mint, pineapple mint, spearmint and apple mint had the strongest effect on A. tumefaciens, and the lowest inhibitory activity was exhibited by the chocolate mint and orange mint essential oils. X. arboricola pv. corylina was the most sensitive to the strawberry mint, pineapple mint and spearmint oils. The chocolate mint oil showed the greatest activity against P. syringae pv. syringae.

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In VitroActivity of Glucosinolates and Their Degradation Products against Brassica-Pathogenic Bacteria and Fungi

Applied and Environmental Microbiology ◽

10.1128/aem.03142-14 ◽

2014 ◽

Vol 81 (1) ◽

pp. 432-440 ◽

Cited By ~ 39

Author(s):

T. Sotelo ◽

M. Lema ◽

P. Soengas ◽

M. E. Cartea ◽

P. Velasco

Keyword(s):

Pseudomonas Syringae ◽

Xanthomonas Campestris ◽

Pathogenic Bacteria ◽

Degradation Products ◽

Allyl Isothiocyanate ◽

Leaf Extracts ◽

Soil Pathogens ◽

Content Type ◽

Positive Effects

ABSTRACTGlucosinolates (GSLs) are secondary metabolites found inBrassicavegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about theirin vitrobiocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enrichedBrassicacrops on suppressingin vitrogrowth of two bacterial (Xanthomonas campestrispv. campestris andPseudomonas syringaepv. maculicola) and two fungal (AlternariabrassicaeandSclerotiniascletoriorum)Brassicapathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of differentBrassicaspecies, have potential to inhibit pathogen growth and offer new opportunities to study the use ofBrassicacrops in biofumigation for the control of multiple diseases.

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