A Green Nanostructured Pesticide to Control Tomato Bacterial Speck Disease

Bacterial speck disease, caused by Pseudomonas syringae pv. tomato (Pst), is one of the most pervasive biological adversities in tomato cultivation, in both industrial and in table varieties. In this work synthesis, biochemical and antibacterial properties of a novel organic nanostructured pesticide composed of chitosan hydrochloride (CH) as active ingredient, cellulose nanocrystals (CNC) as nanocarriers and starch as excipient were evaluated. In order to study the possibility of delivering CH, the effects of two different types of starches, extracted from a high amylose bread wheat (high amylose starch—HA Starch) and from a control genotype (standard starch—St Starch), were investigated. Nanostructured microparticles (NMP) were obtained through the spray-drying technique, revealing a CH loading capacity proximal to 50%, with a CH release of 30% for CH-CNC-St Starch NMP and 50% for CH-CNC-HA Starch NMP after 24 h. Both NMP were able to inhibit bacterial growth in vitro when used at 1% w/v. Moreover, no negative effects on vegetative growth were recorded when NMP were foliar applied on tomato plants. Proposed nanostructured pesticides showed the capability of diminishing Pst epiphytical survival during time, decreasing disease incidence and severity (from 45% to 49%), with results comparable to one of the most used cupric salt (hydroxide), pointing out the potential use of CH-CNC-Starch NMP as a sustainable and innovative ally in Pst control strategies.

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Protection of Tomato Seedlings against Infection by Pseudomonas syringae pv. Tomato by Using the Plant Growth-Promoting Bacterium Azospirillum brasilense

Applied and Environmental Microbiology ◽

10.1128/aem.68.6.2637-2643.2002 ◽

2002 ◽

Vol 68 (6) ◽

pp. 2637-2643 ◽

Cited By ~ 72

Author(s):

Yoav Bashan ◽

Luz E. de-Bashan

Keyword(s):

Plant Growth ◽

Pseudomonas Syringae ◽

Azospirillum Brasilense ◽

Dry Weight ◽

Tomato Plants ◽

Bacterial Speck ◽

Plant Growth Promoting ◽

Bacterial Speck Disease ◽

Growth Promoting ◽

Mist Chamber

ABSTRACT Pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium Azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. The population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. When inoculated onto separate plants, the A. brasilense population in the rhizosphere of tomato plants was 2 orders of magnitude greater than the population of P. syringae pv. tomato (107 versus 105 CFU/g [dry weight] of root). Under mist chamber conditions, the leaf population of P. syringae pv. tomato was 1 order of magnitude greater than that of A. brasilense (107 versus 106 CFU/g [dry weight] of leaf). Inoculation of seeds with a mixed culture of the two bacterial strains resulted in a reduction of the pathogen population in the rhizosphere, an increase in the A. brasilense population, the prevention of bacterial speck disease development, and improved plant growth. Inoculation of leaves with the mixed bacterial culture under mist conditions significantly reduced the P. syringae pv. tomato population and significantly decreased disease severity. Challenge with P. syringae pv. tomato after A. brasilense was established in the leaves further reduced both the population of P. syringae pv. tomato and disease severity and significantly enhanced plant development. Both bacteria maintained a large population in the rhizosphere for 45 days when each was inoculated separately onto tomato seeds (105 to 106 CFU/g [dry weight] of root). However, P. syringae pv. tomato did not survive in the rhizosphere in the presence of A. brasilense. Foliar inoculation of A. brasilense after P. syringae pv. tomato was established on the leaves did not alleviate bacterial speck disease, and A. brasilense did not survive well in the phyllosphere under these conditions, even in a mist chamber. Several applications of a low concentration of buffered malic acid significantly enhanced the leaf population of A. brasilense (>108 CFU/g [dry weight] of leaf), decreased the population of P. syringae pv. tomato to almost undetectable levels, almost eliminated disease development, and improved plant growth to the level of uninoculated healthy control plants. Based on our results, we propose that A. brasilense be used in prevention programs to combat the foliar bacterial speck disease caused by P. syringae pv. tomato.

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Bacteriophytochromes from Pseudomonas syringae pv. tomato DC3000 modulate the early stages of plant colonization during bacterial speck disease

European Journal of Plant Pathology ◽

10.1007/s10658-019-01918-5 ◽

2020 ◽

Vol 156 (3) ◽

pp. 695-712 ◽

Cited By ~ 3

Author(s):

Laura Moyano ◽

Analía Carrau ◽

Silvana Petrocelli ◽

Ivana Kraiselburd ◽

Wolfgang Gärtner ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Plant Colonization ◽

Tomato Dc3000 ◽

Bacterial Speck ◽

Early Stages ◽

Bacterial Speck Disease

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Effects of Streptomyces corchorusii, Streptomyces mutabilis, pendimethalin, and metribuzin on the control of bacterial and Fusarium wilt of tomato

Canadian Journal of Botany ◽

10.1139/b96-126 ◽

1996 ◽

Vol 74 (7) ◽

pp. 1016-1022 ◽

Cited By ~ 18

Author(s):

Abd El-Raheem R. El-Shanshoury ◽

Soad M. Abu El-Sououd ◽

Omima A. Awadalla ◽

Nabila B. El-Bandy

Keyword(s):

Fusarium Oxysporum ◽

Culture Media ◽

Disease Incidence ◽

Inhibitory Effects ◽

Pseudomonas Solanacearum ◽

Negative Effects ◽

Streptomyces Spp ◽

Antagonistic Streptomyces

Two Streptomyces spp. and two herbicides were used to control the pathogens of tomato wilt disease in vitro and in vivo. In vitro studies showed inhibitory effects of Streptomyces corchorusii against Fusarium oxysporum f.sp. lycopersici (Sacc.) and inhibitory effects of Streptomyces mutabilis against Pseudomonas solanacearum. In cultures amended with pendimethalin or metribuzin, the growths of P. solanacearum and F. oxysporum were inhibited. The degree of growth inhibition was proportional to the herbicide concentration, with pendimethalin being more effective than metribuzin, and maximum inhibition was at 2.0 × 10−3 M. The growth of S. corchorusii and S. mutabilis was slightly inhibited or enhanced by the herbicides. Supplementation of the herbicides to culture media of the antagonistic Streptomyces spp. increased their inhibitory effects against P. solanacearum and F. oxysporum that were proportional to the herbicide concentrations. Soaking seeds of tomato in the herbicides prior to sowing in sterilized and raw soils and applying S. corchorusii and (or) S. mutabilis to the soils artificially infested with P. solanacearum and (or) F. oxysporum f.sp. lycopersici (Sacc.) 40 days after transplanting revealed significant interactions that gave better control of wilt than either applied alone. The combination of antagonistic Streptomyces spp. was more effective with pendimethalin than with metribuzin and in nonsterilized soil than in sterilized soil. The combination of pendimethalin with S. corchorusii, S. mutabilis, or S. corchorusii plus S. mutabilis was more effective than the single treatment with microbial antagonists or the herbicide against F. oxysporum, P. solanacearum, and Pseudomonas plus Fusarium, respectively. In both soils, the combination of microbial antagonists with pendimethalin was most effective at 2.0 × 10−3 M, disease incidence being reduced to zero and the percent colonization of either pathogen being the lowest. The results also revealed that these combinations minimized the negative effects of the pathogens on tomato growth. This work demonstrates that two compatible control agents, biological and chemical, can be combined to give additional control of a plant pathogen. Keywords: Streptomyces spp., herbicides, Pseudomonas solanacearum, Fusarium oxysporum f.sp. lycopersici (Sacc.), wilt, Lycopersicon esculentum Mill.

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Assessment of the Importance of Similarity in Carbon Source Utilization Profiles between the Biological Control Agent and the Pathogen in Biological Control of Bacterial Speck of Tomato

Applied and Environmental Microbiology ◽

10.1128/aem.68.9.4383-4389.2002 ◽

2002 ◽

Vol 68 (9) ◽

pp. 4383-4389 ◽

Cited By ~ 42

Author(s):

Pingsheng Ji ◽

Mark Wilson

Keyword(s):

Biological Control ◽

Carbon Source ◽

Disease Severity ◽

Pseudomonas Syringae ◽

Biological Control Agent ◽

Carbon Sources ◽

Control Agent ◽

Carbon Source Utilization ◽

Bacterial Speck

ABSTRACT Bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, was used to determine whether similarity in carbon source utilization between a preemptive biological control agent and the pathogen was significant in determining the ability of the bacterium to suppress disease. Similarity in carbon source utilization was quantified as the ratio of the number of tomato carbon sources utilized in vitro by the biological control agent to the number of tomato carbon sources utilized in vitro by the target pathogen (the niche overlap index [NOI]). Suppression of the disease was quantified as the percent reduction in disease severity compared to the pathogen-only control when nonpathogenic bacteria were applied to foliage 48 h prior to the pathogen. In the collection of 36 nonpathogenic bacterial strains, there was a significant (P < 0.01), but weak (r2 = 0.25), correlation between reduction in disease severity and similarity in carbon source utilization, suggesting that similarity in carbon source use was significant in determining ability to suppress disease. The relationship was investigated further using catabolic mutants of P. syringae strain TLP2, an effective biological control agent of speck. Catabolic mutants exhibited lower levels of similarity (NOI = 0.07 to 0.90) than did wild-type TLP2 (NOI = 0.93). With these catabolic mutants there was a significant (P < 0.01), and stronger (r2 = 0.42), correlation between reduction in disease severity and similarity in carbon source utilization. This suggests that similarity in carbon source utilization was a more important component of biological control ability for the catabolic mutants than for the nonpathogenic bacteria. Together, these studies indicate that suppression of bacterial speck of tomato was correlated with nutritional similarity between the pathogenic and nonpathogenic bacteria and suggest that preemptive utilization of carbon sources was probably involved in the biological control of the disease by both the naturally occurring nonpathogenic bacteria and the catabolic mutants.

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The Ptr1 locus of Solanum lycopersicoides confers resistance to race 1 strains of Pseudomonas syringae pv. tomato and to Ralstonia pseudosolanacearum by recognizing the type III effectors AvrRpt2/RipBN

10.1101/518399 ◽

2019 ◽

Author(s):

Carolina Mazo-Molina ◽

Samantha Mainiero ◽

Sara R. Hind ◽

Christine M. Kraus ◽

Mishi Vachev ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Genetic Resistance ◽

Site Directed Mutagenesis ◽

Type Iii Effector ◽

Bacterial Speck ◽

Solanum Lycopersicoides ◽

Type Iii ◽

Bacterial Speck Disease ◽

Race 1 ◽

Ralstonia Pseudosolanacearum

AbstractRace 1 strains of Pseudomonas syringae pv. tomato, which causes bacterial speck disease of tomato, are becoming increasingly common and no simply-inherited genetic resistance to such strains is known. We discovered that a locus in Solanum lycopersicoides, termed Pseudomonas tomato race 1 (Ptr1), confers resistance to race 1 Pst strains by recognizing the type III effector AvrRpt2. In Arabidopsis, AvrRpt2 degrades the RIN4 protein thereby activating RPS2-mediated immunity. Ptr1 also recognized homologs of AvrRpt2 from diverse bacteria including one in Ralstonia pseudosolanacearum and this correlated with the ability of AvrRpt2 to degrade RIN4. Using site-directed mutagenesis of AvrRpt2 we found that Ptr1 and RPS2 recognize identical features of AvrRpt2. However, the genome sequence of S. lycopersicoides revealed no RPS2 homolog in the Ptr1 region. Ptr1 could play an important role in controlling bacterial speck disease and its future cloning may shed light on an example of convergent evolution for recognition of a widespread type III effector.

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In vitro inhibition of Pseudomonas syringae pv actinidiae by wound protectants

New Zealand Plant Protection ◽

10.30843/nzpp.2015.68.5830 ◽

2015 ◽

Vol 68 ◽

pp. 332-339

Author(s):

D.A. Cornish ◽

J. Yu ◽

J.M. Oldham ◽

J. Benge ◽

W. Max ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Antibacterial Activity ◽

Pseudomonas Syringae ◽

Disease Incidence ◽

Bacterial Canker ◽

Streptomycin Sulphate ◽

Chain Reaction ◽

Commercial Formulation ◽

Polymerase Chain

Preventing Pseudomonas syringae pv actinidiae (Psa) the causal agent of bacterial canker of kiwifruit from entering pruning wounds would reduce disease incidence and facilitate canopy management Antibacterial activity against Psa has been determined in the laboratory for active ingredients commercially available in New Zealand Only tebuconazole tebuconazole with octhilinone and a formulation of cyproconazole and iodocarb killed Psa on agar plates or in liquid medium However only tebuconazole with octhilinone killed Psa within 5 min Psa was detected by polymerase chain reaction following plating on instruments used for applying wound protectants in an infected orchard This suggests that under some conditions the pathogen could be transferred from vine to vine when applying some wound protectants Addition of streptomycin sulphate to tebuconazole or a formulation of cyproconazole and iodocarb did not result in a rapid and complete kill of Psa similar to that with a commercial formulation of streptomycin applied alone

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First Report of Bacterial Speck of Tomato Caused by Pseudomonas syringae pv. tomato in Tanzania

Plant Disease ◽

10.1094/pdis-91-4-0462c ◽

2007 ◽

Vol 91 (4) ◽

pp. 462-462 ◽

Cited By ~ 13

Author(s):

K. C. Shenge ◽

R. B. Mabagala ◽

C. N. Mortensen ◽

D. Stephan ◽

K. Wydra

Keyword(s):

Pseudomonas Syringae ◽

Uv Light ◽

Disease Incidence ◽

Leaf Spot Disease ◽

Polymorphism Analysis ◽

Tomato Fruits ◽

First Report ◽

Bacterial Speck ◽

Small Water ◽

Tomato Seedlings

In April 2004, there was a serious outbreak of a tomato (Lypersicon esculentum Mill.) leaf spot disease in Mgeta, Mvomero District of Tanzania. The disease was characterized by lesions on green tomato fruits that were small, sunken, and black and were surrounded by darker green haloes. Lesions on ripe tomato fruits were dark brown to black, superficial, and measured approximately 1 to 2 mm in diameter. On the leaves, lesions were small, black, and surrounded by chlorotic (yellow) haloes. In some cases, the specks coalesced to form large lesions on older leaves. Black lesions were also observed on stems and petioles. A disease survey of selected tomato-producing areas in Arusha, Dodoma, Iringa, and Morogoro regions of Tanzania during 2004 and 2005 revealed that the disease was widespread in farmers' fields in all areas surveyed. Disease incidence was approximately 80%, while severity, rated on the scale of Chambers and Merriman (1), ranged from moderate (11 to 40 lesions per plant) to severe (>40 lesions per plant). A bacterium that produced a greenish, diffusible pigment on King's medium B was consistently isolated from lesions on tomato fruits collected from the fields in all the surveyed areas. All 56 isolates obtained were gram negative, oxidase negative, and fluoresced on King's medium B under UV light. None utilized phenylethylamine as the sole carbon source, while three isolates utilized i-erythritol and lactulose. Biolog analysis of the isolates, along with two reference strains of P. syringae pv. tomato (Pst CEP-3 from Sokoine University of Agriculture, Tanzania and Pst BB6 [Race 1] from Göttinger Sammlung Phytopathogener Bakterien, Göttingen, Germany) identified them as P. syringae pv. tomato, with similarity indices of 0.518 to 0.933. They also were positively identified as P. syringae pv. tomato by repetitive sequence-based-PCR (2,3) and fragment length polymorphism analysis. Pathogenicity of the strains was confirmed by spraying 35-day-old tomato seedlings (cv. Tanya) with suspensions of the isolates at a concentration of 108 CFU ml-1 of sterile water. After approximately 72 h, small, water-soaked, dark brown lesions similar to those observed on the field plants were observed on leaves of all the inoculated tomato seedlings. There were no symptoms on control plants. The bacterium was reisolated from the infected plants and identified as P. syringae pv. tomato, in accordance with Koch's postulates. To our knowledge, this is the first report of the occurrence of tomato bacterial speck in Tanzania. References: (1). S. C. Chambers and P. R. Merriman. Aust. J. Agric. Res. 26:657, 1975. (2). F. J. Louws et al. Appl. Environ. Microbiol. 60:2286, 1994. (3). M. Zaccardelli et al. Eur. J. Plant Pathol. 111:85, 2005.

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Pto- and Prf-Mediated Recognition of AvrPto and AvrPtoB Restricts the Ability of Diverse Pseudomonas syringae Pathovars to Infect Tomato

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-7-0806 ◽

2007 ◽

Vol 20 (7) ◽

pp. 806-815 ◽

Cited By ~ 46

Author(s):

Nai-Chun Lin ◽

Gregory B. Martin

Keyword(s):

Host Range ◽

Pseudomonas Syringae ◽

Plant Host ◽

Range Restriction ◽

Disease Symptoms ◽

Type Iii Effectors ◽

Bacterial Speck ◽

Type Iii ◽

Tomato Species ◽

Bacterial Speck Disease

The molecular basis underlying the ability of pathogens to infect certain plant species and not others is largely unknown. Pseudomonas syringae is a useful model species for investigating this phenomenon because it comprises more than 50 pathovars which have narrow host range specificities. Tomato (Solanum lycopersicum) is a host for P. syringae pv. tomato, the causative agent of bacterial speck disease, but is considered a nonhost for other P. syringae pathovars. Host resistance in tomato to bacterial speck disease is conferred by the Pto protein kinase which acts in concert with the Prf nucleotide-binding lucine-rich repeat protein to recognize P. syringae pv. tomato strains expressing the type III effectors AvrPto or AvrPtoB (HopAB2). The Pto and Prf genes were isolated from the wild tomato species S. pimpinellifolium and functional alleles of both of these genes now are known to exist in many species of tomato and in other Solanaceous species. Here, we extend earlier reports that avrPto and avrPtoB genes are widely distributed among pathovars of P. syringae which are considered nonhost pathogens of tomato. This observation prompted us to examine the possibility that recognition of these type III effectors by Pto or Prf might contribute to the inability of many P. syringae pathovars to infect tomato species. We show that 10 strains from presumed nonhost P. syringae pathovars are able to grow and cause pathovar-unique disease symptoms in tomato leaves lacking Pto or Prf, although they did not reach the population levels or cause symptoms as severe as a control P. syringae pv. tomato strain. Seven of these strains were found to express avrPto or avrPtoB. The AvrPto- and AvrPtoB-expressing strains elicited disease resistance on tomato leaves expressing Pto and Prf. Thus, a gene-for-gene recognition event may contribute to host range restriction of many P. syringae pathovars on tomato species. Furthermore, we conclude that the diverse disease symptoms caused by different Pseudomonas pathogens on their normal plant hosts are due largely to the array of virulence factors expressed by each pathovar and not to specific molecular or morphological attributes of the plant host.

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Serendipita Species Trigger Cultivar-Specific Responses to Fusarium Wilt in Tomato

Agronomy ◽

10.3390/agronomy9100595 ◽

2019 ◽

Vol 9 (10) ◽

pp. 595 ◽

Cited By ~ 4

Author(s):

Negar Ghezel Sefloo ◽

Krzysztof Wieczorek ◽

Siegrid Steinkellner ◽

Karin Hage-Ahmed

Keyword(s):

Disease Incidence ◽

Dry Mass ◽

In Vitro Assays ◽

Plant Interactions ◽

Inhibitory Effects ◽

Negative Effects ◽

Beneficial Effects ◽

Specific Effects ◽

Tomato Cultivars

The endophytic fungi Serendipita indica and S. vermifera have recently gained increasing attention due to their beneficial effects on plant growth and plant health. Little is known about other species, such as S. williamsii and S. herbamans. To test their biocontrol and growth-promoting potential, susceptible and tolerant tomato cultivars (Kremser Perle and Micro-Tom, respectively) were inoculated with S. williamsii, S. herbamans, S. indica, or S. vermifera and challenged with the soilborne pathogen Fusarium oxysporum f. sp. lycopersici (Fol) in greenhouse experiments. Furthermore, in vitro assays on the direct inhibitory effects of Serendipita spp. against Fol were performed. Negative effects of Fol on phenological growth in the susceptible cultivar were alleviated by all four applied Serendipita spp. Apart from these similar effects on biometric parameters, disease incidence was only reduced by S. herbamans and S. vermifera. In the tolerant cultivar, disease parameters remained unaffected although shoot dry mass was negatively affected by S. vermifera. Direct effects of Serendipita spp. against Fol were not evident in the in vitro assays indicating an indirect effect via the host plant. Our results highlight the importance of identifying cultivar-specific effects in pathogen–endophyte–plant interactions to determine the most beneficial combinations.

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