scholarly journals Lactobacillus plantarum Exopolysaccharides Induce Resistance against Tomato Bacterial Spot

2017 ◽  
Vol 9 (2) ◽  
pp. 162 ◽  
Author(s):  
Juliane Mendes Lemos Blainski ◽  
Argus Cezar da Rocha Neto ◽  
Caroline Luiz ◽  
Márcio José Rossi ◽  
Robson Marcelo Di Piero
Keyword(s):  
Lactobacillus Plantarum ◽  
Defense Mechanisms ◽  
Culture Medium ◽  
Defense Responses ◽  
Total Phenolic ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
Induce Resistance ◽  
Severity Of The Disease

Lactic acid bacteria produce several exopolysaccharides (EPS) that may have antimicrobial action and/or induce defense responses in plants. This work aims to evaluate the potential of EPS produced by Lactobacillus plantarum in the protection of tomato plants against bacterial spot caused by Xanthomonas gardneri, as well as to predict the possible mechanisms of action. The EPS were characterized through FTIR and applied at 0; 0.5; 1.5 and 3.0 mg mL-1 in tomato plants with five expanded leaves, followed by the pathogen inoculation after 3 or 7 days. Antimicrobial activity of the biopolymer (1.5 or 10.0 mg mL-1) was evaluated in bioassay when EPS was incorporated into culture medium or embedded in antibiogram disk. The defense mechanisms i.e., total phenolic compounds and flavonoids content, phenylalanine ammonia-lyase (PAL), glutathione reductase (GR) and lipoxygenase (LOX) activities, were measured in tomato plants treated with EPS (1.5 mg mL-1), inoculated or not with X. gardneri. EPS reduced bacterial spot symptoms by up to 72.0% compared to the control. There were no direct effects of EPS on the in vitro growth of X. gardneri. The spectrophotometric profile, ascorbic and ellagic acid concentrations were change in tomato plants after EPS application, in plants challenged with the pathogen. Increases in PAL, GR and LOX activities were observed in plants treated with EPS. Thus, the application of L. plantarum exopolysaccharides can be considered as an effective alternative for controlling bacterial spot in tomato plants. This paper also discusses how these exopolysaccharides reduced the severity of the disease.

scholarly journals Systemically Induced Resistance and Microbial Competitive Exclusion: Implications on Biological Control

2012 ◽  
Vol 102 (3) ◽  
pp. 260-266 ◽  
Author(s):  
A. Martinuz ◽  
A. Schouten ◽  
R. A. Sikora
Keyword(s):  
Meloidogyne Incognita ◽  
Defense Mechanisms ◽  
Root Colonization ◽  
Competitive Exclusion ◽  
Spatial Separation ◽  
Agricultural Pests ◽  
Root Knot Nematode ◽  
Tomato Plants ◽  
Split Root ◽  
Induce Resistance

The root-knot nematode, Meloidogyne incognita, is among the most damaging agricultural pests, particularly to tomato. The mutualistic endophytes Fusarium oxysporum strain Fo162 (Fo162) and Rhizobium etli strain G12 (G12) have been shown to systemically induce resistance toward M. incognita. By using triple-split-root tomato plants, spatially separated but simultaneous inoculation of both endophytes did not lead to additive reductions in M. incognita infection. More importantly, spatially separated inoculation of Fo162 and G12 led to a reduction in Fo162 root colonization of 35 and 39% when G12 was inoculated on a separate root section of the same plant in two independent experiments. In an additional split-root experiment, spatial separation of Fo162 and G12 resulted in a reduction of Fo162 root colonization of approximately 50% over the water controls in two independent experiments. The results suggested that the suppressive activity of G12 on Fo162 and M. incognita is possibly related to the induction of specific plant defense mechanisms. Thus, although Fo162 and G12 have the ability to systemically repress M. incognita infection in tomato, they can be considered incompatible biocontrol agents when both organisms are present simultaneously on the same root system.

scholarly journals Plant Extract Treatments Induce Resistance to Bacterial Spot by Tomato Plants for a Sustainable System

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 36
Author(s):  
Kamal A. M. Abo-Elyousr ◽  
Najeeb M. Almasoudi ◽  
Ahmed W. M. Abdelmagid ◽  
Sergio R. Roberto ◽  
Khamis Youssef
Keyword(s):  
Antibacterial Activity ◽  
Plant Extracts ◽  
Integrated Management ◽  
Nerium Oleander ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
Sustainable System ◽  
Pathogen Populations

The aim of this study is to assess the effect of extracts of Nerium oleander, Eucalyptus chamadulonsis and Citrullus colocynthis against bacterial spot disease of tomato and to investigate the induction of resistance by tomato (Solanum lycopersicum) in order to promote a sustainable management system. The antibacterial activity of aqueous and ethanol plant extracts was tested against Xanthomonas axonopodis pv. vesicatoria, isolate PHYXV3, in vitro and in vivo. The highest antibacterial activity in vitro was obtained with C. colocynthis, N. oleander and E. chamadulonsis, respectively. In vivo, ethanol extracts of N. oleander and E. chamadulonsis were more effective than aqueous extracts in reducing pathogen populations on tomato leaves. Under greenhouse conditions, application of the plant extracts at 15% (v/v) to tomato plants significantly reduced disease severity and increased the shoot weight of ‘Super Marmande’ tomato. In most cases, plant extracts significantly increased total phenol and salicylic acid content of tomato plants compared to either healthy or infected ones. In addition, C. colocynthis and E. chamadulonsis extracts significantly increased peroxidase activity while only E. chamadulonsis increased polyphenol oxidase after infection with the causal agent. The results indicated that the plant extracts showed promising antibacterial activity and could be considered an effective tool in integrated management programs for a sustainable system of tomato bacterial spot control.

Effects of Oligochitosan on Postharvest Alternaria Rot, Storage Quality, and Defense Responses in Chinese Jujube (Zizyphus jujuba Mill. cv. Dongzao) Fruit

2011 ◽  
Vol 74 (5) ◽  
pp. 783-788 ◽  
Author(s):  
JIAQI YAN ◽  
JIAN LI ◽  
HONGWEI ZHAO ◽  
NI CHEN ◽  
JIANKANG CAO ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Defense Responses ◽  
Soluble Solids ◽  
Total Phenolic ◽  
In Vitro Test ◽  
Postharvest Diseases ◽  
Chinese Jujube ◽  
Jujube Fruit ◽  
Zizyphus Jujuba

Effects of oligochitosan (OCH) on postharvest rot caused by Alternaria alternata in Chinese jujube (Zizyphus jujuba Mill. cv. Dongzao) fruit were investigated. An in vitro test indicated that mycelial growth of A. alternata was strongly suppressed by OCH at 0.5, 1, 2, 5, 10, 15, or 20 g/liter. The half-inhibition concentration of OCH against this fungus was 0.76 and 1.69 g/liter on days 4 and 6 of incubation, respectively. Lesion area and disease incidence in the jujube fruit inoculated with A. alternata were remarkably reduced by the OCH treatments at concentrations higher than 1 g/liter, but 5 g/liter OCH was considered the optimal treatment for inhibiting disease development. OCH also significantly reduced postharvest natural decay, promoted fruit firmness, delayed decline in soluble solids and loss of ascorbic acid, and increased total phenolic compounds during storage at 0°C and 85 to 95% relative humidity. Biochemical evaluations revealed that the activities of the main defense-related enzymes in the jujube fruit, including phenylalanine ammonia–lyase, peroxidase, chitinase, and β-1,3-glucanase, were significantly enhanced (P < 0.05) by OCH treatment. OCH increased superoxide dismutase activity but decreased catalase activity and, consequently, elevated hydrogen peroxide levels in the fruit. These results suggest that OCH might trigger several defense mechanisms in the jujube fruit for disease control in addition to its direct antifungal activity. OCH could be a viable alternative to conventional control of postharvest diseases of horticultural products.

scholarly journals Identifying Beneficial Qualities ofTrichoderma parareeseifor Plants

2014 ◽  
Vol 80 (6) ◽  
pp. 1864-1873 ◽  
Author(s):  
M. Belén Rubio ◽  
Narciso M. Quijada ◽  
Esclaudys Pérez ◽  
Sara Domínguez ◽  
Enrique Monte ◽  
...  
Keyword(s):  
Time Course ◽  
Plant Cell Wall ◽  
Growth Promotion ◽  
Expression Patterns ◽  
Hyphal Growth ◽  
Defense Responses ◽  
Tomato Plants ◽  
Lateral Root Development ◽  
Beneficial Effects

ABSTRACTTrichoderma parareeseiandTrichoderma reesei(teleomorphHypocrea jecorina) produce cellulases and xylanases of industrial interest. Here, the anamorphic strain T6 (formerlyT. reesei) has been identified asT. parareesei, showing biocontrol potential against fungal and oomycete phytopathogens and enhanced hyphal growth in the presence of tomato exudates or plant cell wall polymers inin vitroassays. ATrichodermamicroarray was used to examine the transcriptomic changes in T6 at 20 h of interaction with tomato plants. Out of a total 34,138Trichodermaprobe sets deposited on the microarray, 250 showed a significant change of at least 2-fold in expression in the presence of tomato plants, with most of them being downregulated.T. parareeseiT6 exerted beneficial effects on tomato plants in terms of seedling lateral root development, and in adult plants it improved defense againstBotrytis cinereaand growth promotion under salt stress. Time course expression patterns (0 to 6 days) observed for defense-related genes suggest that T6 was able to prime defense responses in the tomato plants against biotic and abiotic stresses. Such responses undulated, with a maximum upregulation of the jasmonic acid (JA)/ethylene (ET)-relatedLOX1andEIN2genes and the salt toleranceSOS1gene at 24 h and that of the salicylic acid (SA)-relatedPR-1gene at 48 h after T6 inoculation. Our study demonstrates that theT. parareeseiT6-tomato interaction is beneficial to both partners.

scholarly journals Zinc as promoter of growth and biochemical activity in basil cultivars under in vitro conditions

2019 ◽  
pp. 342
Author(s):  
Caroline Galego Comar ◽  
Edinara Maria Barbosa ◽  
Vanusa Souza Rocha Pereira ◽  
Julliane Destro de Lima ◽  
Thiago Teodoro Santana ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Culture Medium ◽  
Total Phenolic ◽  
In Vitro Cultivation ◽  
Biochemical Activity ◽  
Randomized Design ◽  
Number Of Leaves ◽  
Completely Randomized Design

In vitro cultivation of basil allows the manipulation of the concentration of certain micronutrients, commonly neglected by the micropropagation protocols. It is a plant of great economic importance for the cosmetic and pharmaceutical industry, due to the components present in its essential oil. In view of the above, the objective of this study was to evaluate zinc (Zn) concentrations in the micropropagation of basil, in addition to antioxidant activity and total phenolic compounds. Basil seeds, cultivars Manolo and Grecco Palla were oxygenated for 4 h, passed through asepsis and placed in test tubes with MS medium supplemented with 30 g L-1 sucrose and 6.5 g L-1 agar and pH adjusted to 5.8. The treatments were composed by the addition or not of 25 μM of zinc sulfate (ZnSO4) and arranged in a completely randomized design. The tubes containing the seeds and the culture medium were kept in a growth chamber for 90 days. The cultivar Manolo was more sensitive to the addition of ZnSO4 due to the increase in the number of leaves and in the antioxidant activity, however, the addition of this component in the culture medium did not influence the production of phenolic compounds or the activity of the antioxidant enzymes SOD, CAT and APX.

scholarly journals Fenugreek extract application improves plant performance of Alternaria solani infected tomato plants

2021 ◽  
Vol 58 (04) ◽  
pp. 1263-1275
Author(s):  
Rashid Iqbal Khan
Keyword(s):  
Plant Extracts ◽  
Fungal Pathogens ◽  
Early Blight ◽  
Growth Parameters ◽  
Alternaria Solani ◽  
Plant Performance ◽  
Total Phenolic ◽  
Tomato Plants ◽  
Chlorophyll Pigments

Plant extracts (PE’s) has emerged as a safer alternative to manage the fungal pathogens affecting tomato productivity. The current study aimed to evaluate the antimicrobial potential of methanolic fenugreek extract against Alternaria solani, a causal agent of early blight disease in tomato. Fenugreek extract was used at different concentrations of 5%, 10%, 15%, 20% and 25% under in vitro conditions. Results concluded that 25% fenugreek extract significantly reduced the radial growth (2.5 cm) of A. solani under in vitro conditions. Based on in vitro results, three concentrations (5%, 15% and 25%) of fenugreek extract was examined under greenhouse and field conditions. The outcomes expressed that 5% fenugreek extract reduced the disease severity up to 30.19% under greenhouse conditions and up to 40.53% under field trials. Although, application of fenugreek extract had exhibited non-significant impact on vegetative and reproductive growth parameters. However, its application had proved better results as compared to those plants which are infected with A. solani but received zero application of fenugreek extract. Furthermore, the effectiveness of plant extracts was evaluated by variant photosynthetic, antioxidative, polyphenolic and hypersensitive response of A. solani affected tomato plants. The 25% fenugreek extract application had augmented the chlorophyll pigments along with the significant increment of superoxide dismutase (174.16 U mg-1 protein), peroxidase (7.61 µmol min-1 g-1 protein) and catalase activity (4.73 nmol min-1 g-1 protein). Similar outcomes were observed regarding phenolic compounds, where 5% fenugreek extract application had enhanced flavonoid levels (26.62 mg QuE g-1), tannins (1.28 mg TE g-1 extract) and total phenolic contents (2.39 mg GAE g-1) in tomato leaves demonstrating its protective effect against early blight. In dose response, 25% fenugreek extract was most effective in reducing lipid peroxidation and enhancing H2O2 levels. The outcomes of study exhibited the fenugreek extract as an effective strategy to be used against A. solani to control early blight infection in tomato plants. Thus, it can serve as suitable fungicide alternative for resource-poor agriculture areas mainly in developing countries.

Previous herbivory modulates aphid population growth and plant defense responses in a non-model plant, Carthamus tinctorius (Asteraceae)

2021 ◽  
pp. 1-11
Author(s):  
Motahareh Amiri Domari ◽  
Seyed Mozaffar Mansouri ◽  
Mohsen Mehrparvar
Keyword(s):  
Defense Mechanisms ◽  
Induced Defense ◽  
Defense Responses ◽  
Carthamus Tinctorius ◽  
Total Phenolic ◽  
Plant Defense Responses ◽  
Mechanical Wounding ◽  
And Control ◽  
Winged Aphid ◽  
Wild Safflower

Abstract Plants have a variety of defense mechanisms that are often induced following attacks by herbivores; this benefits those plants by decreasing performance or preference of herbivores that attack the plants later. We investigated the effects of previous exposure of plants to the safflower aphid, Uroleucon carthami, cotton bollworm, Helicoverpa armigera, and mechanical wounding on subsequent safflower aphid infestations using commercial safflower (Carthamus tinctorius) cultivars and wild safflower species (C. oxyacantha). The experiments were conducted in a greenhouse with two treatments: previously induced plants via direct herbivory or mechanical wounding, and control plants that had never experienced herbivory. To test the performance of safflower aphid on different plant treatments, five unwinged aphids were placed on each plant and allowed to reproduce for 14 days. Finally, the total numbers of aphids on each plant were counted and the percentage of produced winged individuals was calculated. The number of aphids on plants that were previously infested or injured was significantly lower than in control plants. Percentage of winged aphids was significantly higher on induced plants, which is an indicator for unsuitable conditions. Also, significant increase in total phenolic content and hydrogen peroxide was observed in induced plants, showing that the levels of these compounds were either treatment, cultivar and/or genotype × treatment dependent, highlighting the specificity of these interactions. Overall, among the safflower cultivars the lowest number of aphids and the highest percentage of winged aphid individuals were observed on Mahali-Isfahan cultivar and wild safflower, showing that this cultivar is more sensitive to herbivory and/or responds to it more than other cultivars. These findings could contribute to a better utilization of induced defense in the integrated pest management of safflower fields.

scholarly journals Elicitor-Induced Defense Responses inSolanum lycopersicumagainstRalstonia solanacearum

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Sudhamoy Mandal ◽  
Itishree Kar ◽  
Arup K. Mukherjee ◽  
Priyambada Acharya
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Induced Defense ◽  
Disease Incidence ◽  
Cinnamyl Alcohol Dehydrogenase ◽  
Defense Responses ◽  
Total Phenolic ◽  
Pronounced Increase ◽  
Tomato Plants ◽  
Alcohol Dehydrogenase Activity ◽  
Induced Defense Responses

We investigated on important parameters of induced resistance in hydroponic tomato (Solanum lycopersicum) againstRalstonia solanacearumusing the elicitors chitosan (CHT), salicylic acid (SA), and jasmonic acid (JA). The increase in total phenolic content of roots by the elicitors was significantly higher than control. Most pronounced increase in lignin synthesis was triggered by SA followed by CHT. At 24 h post-elicitation (hpe), the activity of phenylalanine ammonia lyase was 4.5 times higher than control elicited by CHT. The peroxidase activity was about 86 nkat/mg protein at 24 hpe in case of SA and 78 nkat/mg protein in case of CHT. The activity of polyphenol oxidase increased several folds by the elicitors. Cinnamyl alcohol dehydrogenase activity increased to the maximum at 48 hpe under the influence of CHT. The results indicate that the elicitors SA and CHT induced effective defense responses in tomato plants againstR. solanacearum. This was evident from reduced vascular browning and wilting symptoms of tomato plants treated with SA and CHT and challenged subsequently withR. solanacearum. This reduced disease incidence in tomato by SA and CHT may be a result of cell wall strengthening through deposition of lignin and the coincident induction of defense enzymes.

scholarly journals THE PROTECTION OF INTRACELLULAR BRUCELLA AGAINST THERAPEUTIC AGENTS AND THE BACTERICIDAL ACTION OF SERUM

1953 ◽  
Vol 97 (1) ◽  
pp. 77-90 ◽  
Author(s):  
James M. Shaffer ◽  
Carrell J. Kucera ◽  
Wesley W. Spink
Keyword(s):  
Host Cell ◽  
Defense Mechanisms ◽  
Culture Medium ◽  
In Vitro Study ◽  
Therapeutic Agents ◽  
Host Cells ◽  
Bactericidal Action ◽  
Degree Of Certainty ◽  
Therapeutic Measures

A method for the in vitro study of intracellular brucella has been described. Exudative leukocytes containing intracellular brucella have been maintained in vitro in a synthetic tissue culture medium or in human or animal serum. Intracellular brucella are protected in vitro against the lethal action of therapeutic agents or the bactericidal action of serum. This protection of intracellular brucella is dependent upon the presence of an intact, viable host cell. None of the currently available therapeutic agents, whether used alone or in combinations, were capable of killing all intracellular brucella in vitro in 24 hours. A remarkable protection of intracellular brucella against streptomycin has been demonstrated. The most effective reduction in the number of viable intracellular brucella was accomplished by exposure of the host cells to streptomycin plus aureomycin, terramycin, or chloramphenicol. The available evidence suggests that the ability of brucella to localize and remain viable within the cells of an infected host is an important biologic factor in establishing and perpetuating brucella infections, despite therapeutic measures or the operation of the host's humoral defense mechanisms. Reduction of neotetrazolium by leukocytes and brucella in vitro provides a method for assessing the metabolic status of the host cell, but does not discriminate with any degree of certainty a viable from a non-viable intracellular organism.

scholarly journals Effect of biotherapic of Alternaria solani on the early blight of tomato-plant and the in vitro development of the fungus

2021 ◽  
Vol 9 (33) ◽  
pp. 147-155
Author(s):  
Solange Monteiro de Toledo Piza Gomes Carneiro ◽  
Euclides Davidson Bueno Romano ◽  
Erika Pignoni ◽  
Marcus Zulian Teixeira ◽  
Maria Elizabeth da Costa Vasconcelos ◽  
...  
Keyword(s):  
Culture Medium ◽  
Early Blight ◽  
Alternaria Solani ◽  
Wide Distribution ◽  
Tomato Plants ◽  
Factors Affecting ◽  
In Vitro Development ◽  
Significant Difference ◽  
Vitro Development

Background: homeopathy is a means permitted in organic agriculture to control disease and plagues; biotherapics are a practical means for farmers to intervene on the health of plants in agro-ecological systems of production. Tomato-plants can be affected by several diseases, one of the most significant ones in Brazil is early blight, caused by fungus Alternaria solani, due to the damage it causes and its wide distribution in the country. Aims: to establish whether a biotherapic of A. solani may interfere on the in vitro development of the fungus and whether it affects the severity of early blight on tomato-plants in greenhouse. Methods: the effect of the biotherapic on the fungus was evaluated through the percentage of germinated spores under microscope and the growth of colonies in a culture medium. Treatments used were: biotherapic 26cH, 27cH, 28cH, 29cH and 30cH; sterilized distilled water; and diluted and agitated hydroalcoholic solution. The effect of the biotherapic on the development of disease was evaluated in 4 experiments in greenhouse. Plants were kept in vases and subjected to artificial inoculation of the fungus after the application of treatments. Evaluation of disease was carried out through diagrammatic scale. Results: no treatment affected the germination of spores or the development of fungus colonies in the culture medium. In the first test, treatment 26cH differed from water in Tukey’s test at 5% but did not differed from diluted and agitated hydroalcoholic solution. In the second test, treatments 27cH and 28cH showed significant difference from both water and hydroalcoholic solution with an average control of disease of 57% and 62% respectively. The other 2 tests did nor exhibit any significant effect. Conclusions: there was no direct effect of the biotherapic on the fungus, but there was an effect on the severity of the disease. Factors affecting the efficiency of the biotherapic must be better understood before it can be recommended to farmers for the management of early blight in tomato-plants.

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