scholarly journals Cyanide production by Pseudomonas fluorescens helps suppress black root rot of tobacco under gnotobiotic conditions

1989 ◽  
Vol 8 (2) ◽  
pp. 351-358 ◽  
Author(s):  
Christophe Voisard ◽  
Christoph Keel ◽  
Dieter Haas ◽  
Geneviève Dèfago
Keyword(s):  
Pseudomonas Fluorescens ◽  
Root Rot ◽  
Black Root Rot

scholarly journals In-vitro compatibility assay of indigenous Trichoderma and Pseudomonas species and their antagonistic activities against black root rot disease (Fusarium solani) of faba bean (Vicia faba L.)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Alemayehu Dugassa ◽  
Tesfaye Alemu ◽  
Yitbarek Woldehawariat
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Fluorescens ◽  
Faba Bean ◽  
Fusarium Solani ◽  
Root Rot ◽  
Mycelial Growth ◽  
Biocontrol Agents ◽  
Black Root Rot ◽  
Root Rot Disease ◽  
Rot Disease

Abstract Background Faba bean (Vicia faba L.) cultivation is highly challenged by faba bean black root rot disease (Fusarium solani) in high lands of Ethiopia. To ensure sustainable production of faba beans, searching for eco-friendly disease management options is necessary to curb the progress of the disease timely. The indigenous biocontrol agents that suit local environments may effectively strive with in-situ microorganisms and suppress local pathogen strains. This study aimed to screen antagonistic indigenous compatible Trichoderma and Pseudomonas strains against Fusarium solani. In the pathogenicity test, soil-filled pots were arranged in complete random block design and sown with health faba bean seeds. The effect of some fungicides was evaluated against Fusarium by food poisoning methods to compare with the biocontrol agents. The antagonistic efficacy of biocontrol agents and their compatibility was investigated on Potato dextrose agar medium. Results Fusarium solani AAUF51 strain caused an intense root rotting in faba bean plant. The effect of Mancozeb 80% WP at 300 ppm was comparable with Trichoderma and Pseudomonas strains against Fusarium. The mycelial growth of test the pathogen was significantly (P ≤ 0.05) reduced to 86.67 and 85.19% by Trichoderma harzianum AAUW1 and Trichoderma viridae AAUC22 strains in dual culture, respectively. The volatile metabolites of Pseudomonas aeruginosa AAUS31 (77.78%) found the most efficient in reducing mycelial growth of Fusarium followed by Pseudomonas fluorescens AAUPF62 (71.11%) strains. The cell-free culture filtrates of Pseudomonas fluorescens AAUPF62 and Pseudomonas aeruginosa AAUS31 were more efficient than the Trichoderma strain in reducing the growth of Fusarium isolates. There was no zone of inhibition recorded between Trichoderma harzianum AAUW1, Trichoderma viridae AAUC22, Pseudomonas aeruginosa AAUS31, and Pseudomonas fluorescens AAUPF62 strains, hence they were mutually compatible. Conclusions The compatible Trichoderma and Pseudomonas strains showed antagonistic potentiality that could be explored for faba bean protection against black root rot disease and might have a future dual application as biocontrol agents.

Clays involved in suppression of tobacco black root rot by a strain of Pseudomonas fluorescens

1989 ◽  
Vol 21 (3) ◽  
pp. 361-366 ◽  
Author(s):  
Emil Stutz ◽  
Günther Kahr ◽  
Geneviève Défago
Keyword(s):  
Pseudomonas Fluorescens ◽  
Root Rot ◽  
Black Root Rot

scholarly journals Global control in Pseudomonas fluorescens mediating antibiotic synthesis and suppression of black root rot of tobacco.

1992 ◽  
Vol 89 (5) ◽  
pp. 1562-1566 ◽  
Author(s):  
J. Laville ◽  
C. Voisard ◽  
C. Keel ◽  
M. Maurhofer ◽  
G. Defago ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Root Rot ◽  
Global Control ◽  
Black Root Rot ◽  
Antibiotic Synthesis

scholarly journals Characterization of the hcnABC Gene Cluster Encoding Hydrogen Cyanide Synthase and Anaerobic Regulation by ANR in the Strictly Aerobic Biocontrol Agent Pseudomonas fluorescens CHA0

1998 ◽  
Vol 180 (12) ◽  
pp. 3187-3196 ◽  
Author(s):  
Jacques Laville ◽  
Caroline Blumer ◽  
Christine Von Schroetter ◽  
Valeria Gaia ◽  
Geneviève Défago ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Hydrogen Cyanide ◽  
Root Rot ◽  
Type Strain ◽  
Wild Type Strain ◽  
Disease Suppression ◽  
Strictly Aerobic ◽  
Wild Type ◽  
Black Root Rot ◽  
Microaerophilic Conditions

ABSTRACT The secondary metabolite hydrogen cyanide (HCN) is produced byPseudomonas fluorescens from glycine, essentially under microaerophilic conditions. The genetic basis of HCN synthesis inP. fluorescens CHA0 was investigated. The contiguous structural genes hcnABC encoding HCN synthase were expressed from the T7 promoter in Escherichia coli, resulting in HCN production in this bacterium. Analysis of the nucleotide sequence of the hcnABC genes showed that each HCN synthase subunit was similar to known enzymes involved in hydrogen transfer, i.e., to formate dehydrogenase (for HcnA) or amino acid oxidases (for HcnB and HcnC). These similarities and the presence of flavin adenine dinucleotide- or NAD(P)-binding motifs in HcnB and HcnC suggest that HCN synthase may act as a dehydrogenase in the reaction leading from glycine to HCN and CO2. The hcnApromoter was mapped by primer extension; the −40 sequence (TTGGC … .ATCAA) resembled the consensus FNR (fumarate and nitrate reductase regulator) binding sequence (TTGAT … .ATCAA). The gene encoding the FNR-like protein ANR (anaerobic regulator) was cloned from P. fluorescens CHA0 and sequenced. ANR of strain CHA0 was most similar to ANR of P. aeruginosa and CydR of Azotobacter vinelandii. An anr mutant of P. fluorescens (CHA21) produced little HCN and was unable to express an hcnA-lacZ translational fusion, whereas in wild-type strain CHA0, microaerophilic conditions strongly favored the expression of the hcnA-lacZ fusion. Mutant CHA21 as well as an hcn deletion mutant were impaired in their capacity to suppress black root rot of tobacco, a disease caused by Thielaviopsis basicola, under gnotobiotic conditions. This effect was most pronounced in water-saturated artificial soil, where the anr mutant had lost about 30% of disease suppression ability, compared with wild-type strain CHA0. These results show that the anaerobic regulator ANR is required for cyanide synthesis in the strictly aerobic strain CHA0 and suggest that ANR-mediated cyanogenesis contributes to the suppression of black root rot.

scholarly journals Application of Bacillus pumilus isolates for management of black rot disease in strawberry

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Farid Abd-El-Kareem ◽  
Ibrahim E. Elshahawy ◽  
Mahfouz M. M. Abd-Elgawad
Keyword(s):  
Root Rot ◽  
Bacillus Pumilus ◽  
Field Conditions ◽  
Black Rot ◽  
Bacterial Isolates ◽  
Black Root Rot ◽  
Root Rot Disease ◽  
Growth Area ◽  
Rot Disease ◽  
The Impact

Abstract Background Black root rot of strawberry plants caused by Rhizoctonia solani, Fusarium solani, and Pythium sp. is a serious disease in Egypt. Biocontrol agents have frequently proved to possess paramount and safe tools against many diseases. The impact of soil treatments with 3 Bacillus pumilus isolates on black root rot disease of strawberry plants caused by R. solani, F., and Pythium sp. under laboratory and field conditions was examined herein on the commonly used ‘Festival’ strawberry cultivar. To increase the bacterial adhesion and distribution on the roots, each seedling was dipped in bacterial cell suspension at 1 × 108 colony-forming units/ml of each separate bacterial isolate for 30 min then mixed with 5% Arabic gum. Results The tested B. pumilus isolates significantly reduced the growth area of these 3 fungi. The two bacterial isolates Nos. 2 and 3 reduced the growth area by more than 85.2, 83.6, and 89.0% for R. solani, F. solani, and Pythium sp., respectively. Likewise, the 3 bacterial isolates significantly (P ≤ 0.05) inhibited the disease under field conditions. Isolates Nos. 2 and 3 suppressed the disease incidence by 64.4 and 68.9% and disease severity by 65.3 and 67.3%, respectively. The fungicide Actamyl had effect similar to that of the 2 isolates. B. pumilus isolates significantly enhanced growth parameters and yields of strawberry plants; isolates Nos. 2 and 3 raised the yield by 66.7 and 73.3%, respectively. Conclusions Bacillus pumilus isolates could effectively manage the black rot disease in strawberry herein. Due to the significant impact of the root rot disease on strawberry yield, B. pumilus should be further tested to manage the disease on strawberry on large scale in Egypt.

Post-plant strategies for management of black root rot-related decline of perennial strawberry fields

2018 ◽  
Vol 104 ◽  
pp. 78-85 ◽  
Author(s):  
Timothy D. Miles ◽  
Benjamin W. Glass ◽  
Roger W. Sysak ◽  
Annemiek C. Schilder
Keyword(s):  
Root Rot ◽  
Plant Strategies ◽  
Black Root Rot

Rosellinia bunodes (black root rot).

2021 ◽  
Author(s):  
Ulrike Krauss
Keyword(s):  
Root Rot ◽  
Coffea Arabica ◽  
Black Root Rot ◽  
Crop Losses ◽  
The Andes

Abstract Given the difficulty in attributing crop losses solely to R. bunodes, meaningful economic estimates are rare. In coffee (Coffea arabica) in Colombia, losses of $489 ha-1 yr-1 due to Rosellinia have been reported (Bautista and Magdiel, 2000). They were most likely caused by R. bunodes and/or R. pepo. In potato in the Andes, losses due to Rosellinia spp. vary from 20% to 80% and, in prolonged monoculture, can reach 100% (Orellana, 1978).

scholarly journals New occurrences of Botryosphaeriaceae causing black root rot of cassava in Brazil

2014 ◽  
Vol 39 (6) ◽  
pp. 464-470 ◽  
Author(s):  
Alexandre R. Machado ◽  
Danilo B. Pinho ◽  
Saulo A. S. de Oliveira ◽  
Olinto L. Pereira
Keyword(s):  
Root Rot ◽  
Black Root Rot ◽  
New Occurrences
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