scholarly journals Crop Protection against Botrytis cinerea by Rhizhosphere Biological Control Agent Bacillus velezensis XT1

2020 ◽  
Vol 8 (7) ◽  
pp. 992 ◽  
Author(s):  
Laura Toral ◽  
Miguel Rodríguez ◽  
Victoria Béjar ◽  
Inmaculada Sampedro
Keyword(s):  
Defense Mechanisms ◽  
Biological Control Agent ◽  
Disease Incidence ◽  
Crop Protection ◽  
Preventive Treatment ◽  
Control Agent ◽  
Total Biomass ◽  
Hormone Regulation ◽  
Bacillus Velezensis ◽  
Callose Deposition

This study aims to evaluate the use of Bacillus velezensis strain XT1 as a plant growth-promoting rhizobacterium (PGPR) and biocontrol agent against B. cinerea in tomato and strawberry plants. Foliar and radicular applications of strain XT1 increased plant total biomass as compared to the control and B. cinerea-infected plants, with root applications being, on the whole, the most effective mode of treatment. Applications of the bacterium were found to reduce infection parameters such as disease incidence and severity by 50% and 60%, respectively. We analyzed stress parameters and phytohormone content in order to evaluate the capacity of XT1 to activate the defense system through phytohormonal regulation. Overall, the application of XT1 reduced oxidative damage, while the H2O2 and malondialdehyde (MDA) content was lower in XT1-treated and B. cinerea-infected plants as compared to non-XT1-treated plants. Moreover, treatment with XT1 induced callose deposition, thus boosting the response to pathogenic infection. The results of this study suggest that the signaling and activation pathways involved in defense mechanisms are mediated by jasmonic acid (JA) and ethylene hormones, which are induced by preventive treatment with XT1. The study also highlights the potential of preventive applications of strain XT1 to activate defense mechanisms in strawberry and tomato plants through hormone regulation.

scholarly journals Draft Genome Sequence of Bacillus velezensis Strain E68, Isolated from an Oil Battery

2020 ◽  
Vol 9 (24) ◽  
Author(s):  
Nathan Liang ◽  
Suha Jabaji
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
Biological Control Agent ◽  
Draft Genome ◽  
Gene Clusters ◽  
Control Agent ◽  
Biosynthetic Gene ◽  
Bacillus Velezensis ◽  
Biosynthetic Gene Clusters ◽  
Content Type

ABSTRACT Bacillus velezensis strain E68 is a biosurfactant-producing bacterium isolated from an oil battery near Chauvin, Alberta, Canada. Strain E68 exhibited antimicrobial activity against fungal pathogens and could potentially serve as a biological control agent. Its genome was sequenced and annotated, revealing the presence of multiple lipopeptide biosynthetic gene clusters.

scholarly journals Biological Control of Fungal Diseases by Trichoderma aggressivum f. europaeum and Its Compatibility with Fungicides

2021 ◽  
Vol 7 (8) ◽  
pp. 598
Author(s):  
Brenda Sánchez-Montesinos ◽  
Mila Santos ◽  
Alejandro Moreno-Gavíra ◽  
Teresa Marín-Rodulfo ◽  
Francisco J. Gea ◽  
...  
Keyword(s):  
Biological Control ◽  
Growth Rates ◽  
Biological Control Agent ◽  
Disease Incidence ◽  
Management Strategies ◽  
High Growth ◽  
Control Agent ◽  
Antagonistic Activity ◽  
La Mancha

Our purpose was to evaluate the ability of Trichoderma aggressivum f. europaeum as a biological control agent against diseases from fungal phytopathogens. Twelve isolates of T. aggressivum f. europaeum were obtained from several substrates used for Agaricus bisporus cultivation from farms in Castilla-La Mancha (Spain). Growth rates of the 12 isolates were determined, and their antagonistic activity was analysed in vitro against Botrytis cinerea, Sclerotinia sclerotiorum, Fusarium solani f. cucurbitae, Pythium aphanidermatum, Rhizoctonia solani, and Mycosphaerella melonis, and all isolates had high growth rates. T. aggressivum f. europaeum showed high antagonistic activity for different phytopathogens, greater than 80%, except for P. aphanidermatum at approximately 65%. The most effective isolate, T. aggressivum f. europaeum TAET1, inhibited B. cinerea, S. sclerotiorum, and M. melonis growth by 100% in detached leaves assay and inhibited germination of S. sclerotiorum sclerotia. Disease incidence and severity in plant assays for pathosystems ranged from 22% for F. solani to 80% for M. melonis. This isolate reduced the incidence of Podosphaera xanthii in zucchini leaves by 66.78%. The high compatibility by this isolate with fungicides could allow its use in combination with different pest management strategies. Based on the results, T. aggressivum f. europaeum TAET1 should be considered for studies in commercial greenhouses as a biological control agent.

scholarly journals Biological Control of Pear Valsa Canker Caused by Valsa pyri Using Penicillium citrinum

Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 198
Author(s):  
Hongbo Yuan ◽  
Bingke Shi ◽  
Tianxiang Huang ◽  
Zengqiang Zhou ◽  
Li Wang ◽  
...  
Keyword(s):  
Biological Control ◽  
Antifungal Activity ◽  
Biological Control Agent ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Control Agent ◽  
Penicillium Citrinum ◽  
Lesion Length ◽  
Dual Culture ◽  
Valsa Canker

Valsa canker caused by Valsa pyri is one of the most destructive diseases of commercial pear. For the present analysis, 29 different endophytic fungal strains were isolated from the branches of a healthy pear tree. In dual culture assays, strain ZZ1 exhibited robust antifungal activity against all tested pathogens including Valsa pyri. Microscopic analyses suggested that following co-culture with ZZ1, the hyphae of V. pyri were ragged, thin, and ruptured. ZZ1 also induced significant decreases in lesion length and disease incidence on detached pear branches inoculated with V. pyri. ZZ1 isolate-derived culture filtrates also exhibited antifungal activity against V. pyri, decreasing mycelial growth and conidium germination and inhibiting V. pyri-associated lesion development on pear branches. These results suggest that the ZZ1 isolate has the potential for use as a biological control agent against V. pyri. The strain was further identified as Penicillium citrinum based on its morphological characteristics and molecular analyses. Overall, these data highlight a potentially valuable new biocontrol resource for combating pear Valsa canker.

scholarly journals Bacillus velezensis WZ-37, a New Broad-Spectrum Biocontrol Strain, Promotes the Growth of Tomato Seedlings

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 581
Author(s):  
Xiuling Chen ◽  
Haifeng Huang ◽  
Shumei Zhang ◽  
Yao Zhang ◽  
Jingbin Jiang ◽  
...  
Keyword(s):  
Biological Control ◽  
Broad Spectrum ◽  
Biological Control Agent ◽  
Storage Period ◽  
Dry Weight ◽  
Gray Mold ◽  
Control Agent ◽  
Soluble Solids ◽  
Bacillus Velezensis ◽  
Tomato Seedlings

A biological control agent is arguably an ideal alternative to chemical fungicide for the prevention and control of gray mold disease. During this process, a biological control produces low levels of pollution, generates few residues that pose no risk to the environment, and pathogens cannot gain resistance to it easily. A new antifungal strain isolated from plant rhizosphere exhibited high antifungal activity against the phytopathogens Botrytis cinerea, Fusarium oxysporum f. sp. cucumerinum, F. moniliforme, Sclerotinia sclerotiorum, Colletotrichum orbiculare, Alternaria nees, F. equiseti, and F. oxysporum f. sp. lycopersici. It was identified as Bacillus velezensis WZ-37 by morphological and physiological indices and comparisons of 16S rRNA and gyrB genes. WZ-37 can significantly inhibit the mycelia growth of B. cinerea by 96.97%. It can reduce a tomato fruit’s decay rate after 21 days of storage by 33.33% (13.34% less for the control) without significantly affecting its firmness and soluble solids. Plant height, stem diameter, and the fresh and dry weight of tomato seedlings were significantly increased when their seeds were soaked in a WZ-37 suspension (106 cfu/mL) for 3 h and grown for 21 days in soil. WZ-37 has broad-spectrum biocontrol and can prolong a tomato’s storage period and enhance its seedlings’ growth, making it a promising candidate strain for broad-spectrum biocontrol applications in agriculture.

scholarly journals Evaluation of Strategies and Implementation of Biological Control of Fire Blight

1993 ◽  
Author(s):  
Steven E. Lindow ◽  
Shulamit Manulis ◽  
Dan Zutra ◽  
Dan Gaash
Keyword(s):  
Biological Control ◽  
Fire Blight ◽  
Biological Control Agent ◽  
Disease Incidence ◽  
Freezing Temperature ◽  
Plasmid Profile ◽  
Control Agent ◽  
Bacterial Strains ◽  
Antagonistic Microorganisms ◽  
Population Sizes

The main objective of this study was to develop data that would facilitate a consistently effective method of biological control of fire blight disease to be developed and to enable its implementation for disease control by ensuring its compatibility with variations in the biological, environmental, and chemical conditions present in pear orchards. As considerable information on the pathogen and biological control of fire blight was already gathered from studies in California and elsewhere, an emphasis was placed on investigating the genetics and ecology of Erwinia amylovora, the causal agent of fire blight in Israel. Studies of plasmid profile, virulence on several host, serological characteristics, as well as DNA fingerprints with selected primers all revealed E. amylovora strains in Israel to be homogeneous. Strains did vary in their resistance to streptomycin, with those from more northern locations being resistant while those in the southern costal plain were all sensitive to streptomycin. Resistance appeared to be conferred by chromosomal mutations as in streptomycin-resistant strains in California. The biological control agent Pseudomonas fluorescens strain A506 colonized flowers of both the Costia and Spodona pear cultivars in Israel as well as Bartlett pear in California. Flowers that were open at the time of spray inoculation of trees subsequently harbored from 105 to 107 cells of strain A506 per flower, while those that opened subsequent to spraying developed population sizes of about 105 cells/flower within 5 days. The incidence of fire blight infections were reduced about 3-fold in several trials in which moderate amounts of disease occurred in the plot areas; this degree of biological control is similar to that observed in California and elsewhere. On two occasions warm and moist weather that favored disease led to epidemics in which nearly all flowers became infected and which was so severe that neither P. fluorescens strain A506 nor chemical bactericides reduced disease incidence. A novel method for identifying antagonistic microorganisms for biological control of fire blight and other diseases was developed. A bacterial ice nucleation gene was introduced into E. amylovora to confer an Ice+ phenotype and the population sizes of this modified pathogen on flowers that had been pre-treated with potential control agents was estimated by measuring the freezing temperature of colonized flowers. Antagonistic strains that prevented the growth of E. amylovora in flowers were readily detected as those in which flowers froze at a low temperature. The method is both rapid and unbiased and several bacterial strains with substantial biological control potential have been identified using this method.

scholarly journals Host Impact and Specificity of Tortoise Beetle (Cassida rubiginosa) on Canada Thistle (Cirsium arvense) in Iran

2013 ◽  
Vol 27 (2) ◽  
pp. 405-411 ◽  
Author(s):  
Ghorbanali Asadi ◽  
Reza Ghorbani ◽  
Javad Karimi ◽  
Alireza Bagheri ◽  
Heinz Mueller-Schaerer
Keyword(s):  
Biological Control Agent ◽  
Control Agent ◽  
Total Biomass ◽  
Weed Species ◽  
Canada Thistle ◽  
Crop Species ◽  
Multiple Choice Tests ◽  
Growing Period ◽  
Parallel Data ◽  
Tortoise Beetle

This study determined the potential of the tortoise beetle (Coleoptera: Chrysomelidae) to control Canada thistle (Asteraceae) in Iran. Genetic analysis of the tortoise beetle, based on mitochondrial DNA, confirmed the presence of the species in Iran. A field experiment using five insect densities (0 to 20 larvae plant−1) showed a positive correlation between the number of larvae transferred and impact. Feeding by 20 larvae reduced total biomass of Canada thistle by 78% and the number of capitula by 94%. More important, when grown in competition with wheat, four and eight egg batches (corresponding to approximately 12 and 24 larvae) per Canada thistle plant increased wheat ear weight by 46 and 82%, respectively. Host range studies with 22 crop and 21 weed species using no-choice and multiple-choice tests under laboratory and field conditions and parallel data from a field survey showed that joint feeding and oviposition were restricted to Canada thistle and a few other weed species. Limited feeding, without oviposition, was recorded on an additional seven weed species but also on safflower (10 to 15% reduction in biomass), and common sunflower (< 10%); the latter only under no-choice conditions. The growing period of either crop species, however, does not coincide with the feeding period of the tortoise beetle in the field. Findings indicate that the tortoise beetle is a promising biological control agent for Canada thistle in arable crops and grasslands in Iran. Other complementary methods will likely be needed to prevent substantial yield losses.

scholarly journals Field Evaluation of Phomopsis amaranthicola, A Biological Control Agent of Amaranthus spp.

Plant Disease ◽  
2000 ◽  
Vol 84 (11) ◽  
pp. 1225-1230 ◽  
Author(s):  
E. N. Rosskopf ◽  
R. Charudattan ◽  
J. T. DeValerio ◽  
W. M. Stall
Keyword(s):  
Biological Control Agent ◽  
Disease Incidence ◽  
Field Evaluation ◽  
Field Trials ◽  
Control Agent ◽  
Fungal Species ◽  
Leafy Vegetables ◽  
Plant Mortality ◽  
Second Year ◽  
Amaranthus Spp

There are approximately 60 species in the genus Amaranthus, of which seven are used as grains, leafy vegetables, or ornamentals. The majority of the remaining species are considered important weeds. A new fungal species, Phomopsis amaranthicola, isolated from stem and leaf lesions on an Amaranthus sp. plant, was found to be pathogenic to 22 species of Amaranthus tested. The efficacy of this fungus was tested in field trials using one or two postemergent applications of the fungus consisting of two concentrations of conidia or mycelial suspensions. Species tested for susceptibility in the field included Amaranthus hybridus, A. lividus, A. viridus, A. spinosus, and a triazine-resistant A. hybridus. The cumulative disease incidence data for each treatment within each species were plotted versus time using regression for lifetime data. Plant mortality was recorded 2, 4, and 6 weeks after inoculation. There were significant differences between the treatment effects in the control plots versus the plots treated with P. amaranthicola. The highest level of control was obtained in the first trial when the fungus was applied at 6 × 107 conidia per ml. Final mortality of all species, except A. hybridus, reached 100% in inoculated plots 25 days earlier than in noninoculated control plots. Conidial suspensions were more effective in controlling the species in the second trial than were mycelial suspensions. Spread of the pathogen to noninoculated control plots was faster in the second year than in other years. High levels of plant mortality were achieved in plots of A. spinosus, A. lividus, and A. viridis. A. hybridus and the triazine-resistant A. hybridus were not effectively controlled in the second year due to the advanced stage of plant growth (8 to 10 true leaves) at the time of pathogen application. Results confirmed that P. amaranthicola is an effective biocontrol agent of some of the Amaranthus spp. tested.

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