Siderophore-mediated competition for iron and induced resistance in the suppression of fusarium wilt of carnation by fluorescent Pseudomonas spp

1993 ◽  
Vol 99 (5-6) ◽  
pp. 277-289 ◽  
Author(s):  
Ben J. Duijff ◽  
Jan W. Meijer ◽  
Peter A. H. M. Bakker ◽  
Bob Schippers
2017 ◽  
Vol 53 (No. 2) ◽  
pp. 78-84 ◽  
Author(s):  
Boukerma Lamia ◽  
Benchabane Messaoud ◽  
Charif Ahmed ◽  
Khélif Lakhdar

The potential of Pseudomonas fluorescens PF15 and Pseudomonas putida PP27 to protect tomato plants against Fusarium wilt under greenhouse conditions was evaluated. In vitro antagonism showed a significant inhibition of the pathogen growth (47%) revealed by PF15. However, PP27 presented a 10% rate of the mycelium inhibition. An in situ experiment was conducted with split-root design for induced systemic resistance (ISR) and without split-root design to measure both ISR and antagonistic activities. Fluorescent Pseudomonas revealed a delay in the onset of symptoms and slower kinetics of disease progression compared to the pathogen control. McKinney’s index, which measures the severity of the disease, was reduced by 37–72%, and the levels of infection (incidence) by 7–36%.


2014 ◽  
Vol 9 (3) ◽  
pp. 101-110 ◽  
Author(s):  
Praveen Kumar Goteti ◽  
Suseelendra Desai ◽  
Leo Daniel Amalraj Em ◽  
Minakshi Taduri ◽  
Uzma Sultana

2019 ◽  
Vol 7 (2) ◽  
pp. 57 ◽  
Author(s):  
Xue Jin ◽  
Jian Wang ◽  
Dalong Li ◽  
Fengzhi Wu ◽  
Xingang Zhou

Crop monocropping usually results in an enrichment of soil-borne pathogens in soil. Crop rotation is an environmentally friendly method for controlling soil-borne diseases. Plant rhizosphere microorganisms, especially plant-beneficial microorganisms, play a major role in protecting plants from pathogens, but responses of these microorganisms to crop rotation remain unclear. Here, we evaluated the effects of rotations with Indian mustard (Brassica juncea) and wild rocket (Diplotaxis tenuifolia (L.) DC.) on cucumber Fusarium wilt disease caused by Fusarium oxysporum f.sp. cucumerinum Owen (FOC). Cucumber rhizosphere bacterial community composition was analyzed by high-throughput amplicon sequencing. Bacteria, Pseudomonas spp., 2,4-diacetylphloroglucinol (an antifungal secondary metabolite) producer and FOC abundances were estimated by real-time PCR. Rotations with Indian mustard and wild rocket suppressed cucumber Fusarium wilt disease and cucumber rhizosphere FOC abundance. Crop rotations increased cucumber rhizosphere bacteria, Pseudomonas spp. and 2,4-diacetylphloroglucinol producer abundances. Moreover, crop rotations changed cucumber rhizosphere bacterial community composition and increased bacterial community diversity. However, crop rotations decreased soil inorganic nitrogen content and inhibited cucumber seedling growth. Overall, rotations with Indian mustard and wild rocket suppressed cucumber Fusarium wilt disease, which might be linked to the increased rhizosphere bacterial diversity and abundances of potential plant-beneficial microorganisms (such as Pseudomonas spp. and 2,4-diacetylphloroglucinol producer).


1999 ◽  
Vol 89 (6) ◽  
pp. 470-475 ◽  
Author(s):  
Jos M. Raaijmakers ◽  
Robert F. Bonsall ◽  
David M. Weller

The role of antibiotics in biological control of soilborne pathogens, and more generally in microbial antagonism in natural disease-suppressive soils, often has been questioned because of the indirect nature of the supporting evidence. In this study, a protocol for high pressure liquid chromatography/mass spectrometry is described that allowed specific identification and quantitation of the antibiotic 2,4-diacetylphloroglucinol (Phl) produced by naturally occurring fluorescent Pseudomonas spp. on roots of wheat grown in a soil suppressive to take-all of wheat. These results provide, for the first time, biochemical support for the conclusion of previous work that Phl-producing fluorescent Pseudomonas spp. are key components of the natural biological control that operates in take-all—suppressive soils in Washington State. This study also demonstrates that the total amount of Phl produced on roots of wheat by P. fluorescens strain Q2-87, at densities ranging from approximately 105 to 107 CFU/g of root, is proportional to its rhizosphere population density and that Phl production per population unit is a constant (0.62 ng/105 CFU). Thus, Phl production in the rhizosphere of wheat is strongly related to the ability of the introduced strain to colonize the roots.


2011 ◽  
Vol 101 (12) ◽  
pp. 1481-1491 ◽  
Author(s):  
Ming-Ming Yang ◽  
Dmitri V. Mavrodi ◽  
Olga V. Mavrodi ◽  
Robert F. Bonsall ◽  
James A. Parejko ◽  
...  

Take-all disease of wheat caused by the soilborne fungus Gaeumannomyces graminis var. tritici is one of the most important root diseases of wheat worldwide. Bacteria were isolated from winter wheat from irrigated and rainfed fields in Hebei and Jiangsu provinces in China, respectively. Samples from rhizosphere soil, roots, stems, and leaves were plated onto King's medium B agar and 553 isolates were selected. On the basis of in vitro tests, 105 isolates (19% of the total) inhibited G. graminis var. tritici and all were identified as Pseudomonas spp. by amplified ribosomal DNA restriction analysis. Based on biocontrol assays, 13 strains were selected for further analysis. All of them aggressively colonized the rhizosphere of wheat and suppressed take-all. Of the 13 strains, 3 (HC9-07, HC13-07, and JC14-07, all stem endophytes) had genes for the biosynthesis of phenazine-1-carboxylic acid (PCA) but none had genes for the production of 2,4-diacetylphloroglucinol, pyoluteorin, or pyrrolnitrin. High-pressure liquid chromatography (HPLC) analysis of 2-day-old cultures confirmed that HC9-07, HC13-07, and JC14-07 produced PCA but no other phenazines were detected. HPLC quantitative time-of-flight 2 mass-spectrometry analysis of extracts from roots of spring wheat colonized by HC9-07, HC13-07, or Pseudomonas fluorescens 2-79 demonstrated that all three strains produced PCA in the rhizosphere. Loss of PCA production by strain HC9-07 resulted in a loss of biocontrol activity. Analysis of DNA sequences within the key phenazine biosynthesis gene phzF and of 16S rDNA indicated that strains HC9-07, HC13-07, and JC14-07 were similar to the well-described PCA producer P. fluorescens 2-79. This is the first report of 2-79-like bacteria being isolated from Asia.


Sign in / Sign up

Export Citation Format

Share Document