scholarly journals Identification of Root-Secreted Compounds Involved in the Communication Between Cucumber, the Beneficial Bacillus amyloliquefaciens, and the Soil-Borne Pathogen Fusarium oxysporum

2017 ◽  
Vol 30 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Yunpeng Liu ◽  
Lin Chen ◽  
Gengwei Wu ◽  
Haichao Feng ◽  
Guishan Zhang ◽  
...  
Keyword(s):  
Fusarium Oxysporum ◽  
Root System ◽  
Root Exudates ◽  
Bacillus Amyloliquefaciens ◽  
Root Colonization ◽  
Plant Root ◽  
Root Exudation ◽  
Soil Borne Pathogens ◽  
Split Root System ◽  
Cucumber Roots

Colonization of plant growth–promoting rhizobacteria (PGPR) is critical for exerting their beneficial effects on the plant. Root exudation is a major factor influencing the colonization of both PGPR and soil-borne pathogens within the root system. However, the tripartite interaction of PGPR, plant roots, and soil-borne pathogens is poorly understood. We screened root exudates for signals that mediate tripartite interactions in the rhizosphere. In a split-root system, we found that root colonization of PGPR strain Bacillus amyloliquefaciens SQR9 on cucumber root was significantly enhanced by preinoculation with SQR9 or the soil-borne pathogen Fusarium oxysporum f. sp. cucumerinum, whereas root colonization of F. oxysporum f. sp. cucumerinum was reduced upon preinoculation with SQR9 or F. oxysporum f. sp. cucumerinum. Root exudates from cucumbers preinoculated with SQR9 or F. oxysporum f. sp. cucumerinum were analyzed and 109 compounds were identified. Correlation analysis highlighted eight compounds that significantly correlated with root colonization of SQR9 or F. oxysporum f. sp. cucumerinum. After performing colonization experiments with these chemicals, raffinose and tryptophan were shown to positively affect the root colonization of F. oxysporum f. sp. cucumerinum and SQR9, respectively. These results indicate that cucumber roots colonized by F. oxysporum f. sp. cucumerinum or SQR9 increase root secretion of tryptophan to strengthen further colonization of SQR9. In contrast, these colonized cucumber roots reduce raffinose secretion to inhibit root colonization of F. oxysporum f. sp. cucumerinum.

Plants colonized by AM fungi regulate further root colonization by AM fungi through altered root exudation

1999 ◽  
Vol 77 (6) ◽  
pp. 891-897 ◽  
Author(s):  
Alexandra Pinior ◽  
Urs Wyss ◽  
Yves Piché ◽  
Horst Vierheilig
Keyword(s):  
Root Exudates ◽  
Glomus Mosseae ◽  
Glomus Intraradices ◽  
Root Colonization ◽  
Root Exudation ◽  
Axenic Culture ◽  
Am Fungi ◽  
Hyphal Growth ◽  
Gigaspora Rosea ◽  
Stimulation Of

The effect of root exudates from non-mycorrhizal and mycorrhizal cucumber (Cucumis sativus L.) plants colonized by one of three arbuscular mycorrhizal fungi (Gigaspora rosea Nicolson & Schenck, Glomus intraradices Smith & Schenck, or Glomus mosseae (Nicolson & Gerdemann) Gerd. & Trappe) on hyphal growth of Gi. rosea and G. intraradices in axenic culture and on root colonization by G. mosseae in soil was investigated. Root exudates from non-mycorrhizal cucumber plants clearly stimulated hyphal growth, whereas root exudates from all mycorrhizal cucumber plants tested showed no stimulation of the hyphal growth of Gi. rosea and only a slight stimulation of the hyphal growth of G. intraradices. Moreover, root exudates from all mycorrhizal cucumber plants inhibited root colonization by G. mosseae compared with the water-treated controls. These results suggest that plants colonized by AM fungi regulate further mycorrhization via their root exudates.Key words: Glomales, Gigaspora rosea, Glomus intraradices, Glomus mosseae, root exudates, regulation.

An altered root exudation pattern through mycorrhization affecting microconidia germination of the highly specialized tomato pathogen Fusarium oxysporum f. sp. lycopersici (Fol) is not tomato specific but also occurs in Fol nonhost plants

2007 ◽  
Vol 85 (3) ◽  
pp. 347-352 ◽  
Author(s):  
Stephan Scheffknecht ◽  
Marc St-Arnaud ◽  
Thanasan Khaosaad ◽  
Siegrid Steinkellner ◽  
Horst Vierheilig
Keyword(s):  
Fusarium Oxysporum ◽  
Root Exudates ◽  
Glomus Mosseae ◽  
Arbuscular Mycorrhizal Fungus ◽  
Root Exudation ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Tomato Pathogen

The effect of root exudates from plants colonized or noncolonized by the arbuscular mycorrhizal fungus Glomus mosseae on microconidia germination of Fusarium oxysporum f. sp. lycopersici (Fol) was studied. Root exudates from the Fol-host tomato and root exudates from Fol nonhost plants were tested. Root exudates from all tested plants stimulated microconidia germination. Mycorrhization increased the stimulatory effect exhibited by the root exudates from the Fol host tomato and from all Fol nonhost plants, showing that similar changes occur in the root exudates of all plants after mycorrhization.

scholarly journals Organic acids from root exudates of banana help root colonization of PGPR strain Bacillus amyloliquefaciens NJN-6

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Jun Yuan ◽  
Nan Zhang ◽  
Qiwei Huang ◽  
Waseem Raza ◽  
Rong Li ◽  
...  
Keyword(s):  
Organic Acids ◽  
Root Exudates ◽  
Bacillus Amyloliquefaciens ◽  
Root Colonization ◽  
Pgpr Strain

scholarly journals Plant-Microbe Communication Enhances Auxin Biosynthesis by a Root-Associated Bacterium, Bacillus amyloliquefaciens SQR9

2016 ◽  
Vol 29 (4) ◽  
pp. 324-330 ◽  
Author(s):  
Yunpeng Liu ◽  
Lin Chen ◽  
Nan Zhang ◽  
Zunfeng Li ◽  
Guishan Zhang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root System ◽  
Bacillus Amyloliquefaciens ◽  
Fold Increase ◽  
Root Surface ◽  
Root Surface Area ◽  
Growth Enhancement ◽  
Split Root ◽  
Split Root System ◽  
Bacterium Bacillus

Mechanisms by which beneficial rhizobacteria promote plant growth include tryptophan-dependent indole-3-acetic acid (IAA) synthesis. The abundance of tryptophan in the rhizosphere, however, may influence the level of benefit provided by IAA-producing rhizobacteria. This study examined the cucumber-Bacillus amyloliquefaciens SQR9 system and found that SQR9, a bacterium previously shown to enhance the growth of cucumber, increased root secretion of tryptophan by three- to fourfold. Using a split-root system, SQR9 colonization of roots in one chamber not only increased tryptophan secretion from the noninoculated roots but also increased the expression of the cucumber tryptophan transport gene but not the anthranilate synthesis gene in those roots. The increased tryptophan in isolated rhizosphere exudates was sufficient to support increased IAA production by SQR9. Moreover, SQR9 colonization of roots in one chamber in the split-root system resulted in sufficient tryptophan production by the other roots to upregulate SQR9 IAA biosynthesis genes, including a 27-fold increase in the indole-3-acetonitrilase gene yhcX during subsequent colonization of those roots. Deletion of yhcX eliminated SQR9-mediated increases in root surface area, likely by reducing IAA-stimulated lateral root growth. This study demonstrates a chemical dialogue between B. amyloliquefaciens and cucumber in which this communication contributes to bacteria-mediated plant-growth enhancement.

Fusarium oxysporum endophytes induced systemic resistance against Radopholus similis on banana

Nematology ◽  
2006 ◽  
Vol 8 (6) ◽  
pp. 847-852 ◽  
Author(s):  
Tam Vu ◽  
Richard Sikora ◽  
Rüdiger Hauschild
Keyword(s):  
Fusarium Oxysporum ◽  
Root System ◽  
Endophytic Fungi ◽  
Fungal Endophyte ◽  
Systemic Resistance ◽  
Root Penetration ◽  
Radopholus Similis ◽  
Split Root ◽  
Split Root System ◽  
Burrowing Nematode

AbstractFour mutualistic endophytic fungal isolates were investigated for their ability to induce systemic resistance in banana toward the burrowing nematode, Radopholus similis in glasshouse experiments. Two isolates of Fusarium oxysporum and one of F. cf. diversisporum isolated from the cortical tissue of banana, and another isolate of F. oxysporum isolated from tomato, were compared. When the root systems of seedling banana plants were pre-inoculated with the four endophytic fungi, R. similis root penetration was reduced by 29-39% and 22-41% 5 and 15 days after nematode inoculation, respectively. Induction of systemic resistance to R. similis in banana roots by the same endophytic fungi was tested in a split-root system. Depending on the isolate, the penetration rates decreased between 30-38.5% and 26.7-45% after 5 and 15 days in the untreated half of the split-root system of plants treated with the endophytic strains when compared to those treated without the fungi. This is the first time that systemic resistance induced by a fungal endophyte has been demonstrated in banana.

The Rhizobium sp. strain NGR234 systemically suppresses arbuscular mycorrhizal root colonization in a split-root system of barley (Hordeum vulgare)

2010 ◽  
pp. no-no ◽  
Author(s):  
Thanasan Khaosaad ◽  
Christian Staehelin ◽  
Siegrid Steinkellner ◽  
Karin Hage-Ahmed ◽  
Juan Antonio Ocampo ◽  
...  
Keyword(s):  
Hordeum Vulgare ◽  
Root System ◽  
Root Colonization ◽  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Root ◽  
Split Root ◽  
Split Root System ◽  
Rhizobium Sp

scholarly journals Effects of Association of Barley Plants with Hydrocarbon-Degrading Bacteria on the Content of Soluble Organic Compounds in Clean and Oil-Contaminated Sand

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 975
Author(s):  
Sergey Chetverikov ◽  
Lidiya Vysotskaya ◽  
Elena Kuzina ◽  
Tatiana Arkhipova ◽  
Margarita Bakaeva ◽  
...  
Keyword(s):  
Organic Acids ◽  
Organic Compounds ◽  
Root Exudates ◽  
Bacterial Production ◽  
Plant Root ◽  
Root Exudation ◽  
Bacterial Inoculation ◽  
Degrading Bacteria ◽  
Petroleum Contaminated Soil ◽  
Organic Acids And Sugars

Plant-bacteria consortia are more effective in bioremediation of petroleum contaminated soil than when either organism is used individually. The reason for this is that plant root exudates promote growth and activity of oil degrading bacteria. However, insufficient attention has been paid to the ability of bacteria to influence root exudation. Therefore, the influence of barley plants and/or bacterial inoculation (Pseudomonas hunanensis IB C7 and Enterobacter sp. UOM 3) on the content of organic acids, sugars and plant hormones in the eluate from clean and oil-polluted sand was studied separately or in combination. These strains are capable of oxidizing hydrocarbons and synthesizing auxins. Concentrations of organic acids and sugars were determined using capillary electrophoresis, and hormones by enzyme-linked immunosorbent assays. In the absence of plants, no sugars were detected in the sand, confirming that root exudates are their main source. Introducing bacteria into the sand increased total contents of organic compounds both in the presence and absence of oil. This increase could be related to the increase in auxin amounts in the sand eluate, as well as in plants. The results indicate that bacteria are able to increase the level of root exudation. Since auxins can promote root exudation, bacterial production of this hormone is likely responsible for increased concentrations of soluble organic compounds in the sand. Bacterial mediation of root exudation by affecting plant hormonal status should be considered when choosing microorganisms for phytoremediation.

Reduced root secretion of valine in Rosa-microbe interaction contributes to the decreased colonization of pathogenic Agrobacterium tumefaciens

Plant Disease ◽  
2020 ◽  
Author(s):  
LIN CHEN ◽  
Qinghua Ma ◽  
Huihui Liu ◽  
Lusen Bian ◽  
XINGHONG WANG ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Root System ◽  
Disease Severity ◽  
Root Exudates ◽  
Crown Gall ◽  
Crown Gall Disease ◽  
Positive Effects ◽  
Split Root ◽  
Split Root System ◽  
The Rose

Root exudates play a critical role in root-microbe interactions. Agrobacterium tumefaciens causes crown gall disease in multiple plant species, but the rose root exudates-mediated inhibition of Agrobacterium in the rhizosphere is poorly understood. In this study, the influence of preinoculation with beneficial bacteria or pathogens on root exudates and subsequent colonization by A. tumefaciens was investigated in a split-root system. We found that preinoculation of rose plants in a split-root system with Bacillus velezensis CLA178 or A. tumefaciens C58 inhibited the subsequent colonization by C58. The root secretion of valine had positive effects on the chemotaxis, biofilm formation, colonization of C58 and crown gall disease severity, but the secretion of valine decreased significantly when Rosa multiflora plants were preinoculated with CLA178 or C58. These results indicated that the rose plants reduced the root secretion of valine in response to microbial colonization, thereby reducing the colonization of Agrobacterium and disease severity. This study provides new insights into the root exudates-mediated interactions of rose plants, B. velezensis and A. tumefaciens, and proposes a potential way for controlling crown gall disease.

scholarly journals Action of plant root exudates in bioremediations: a review

2011 ◽  
Vol 59 (1) ◽  
pp. 303-308 ◽  
Author(s):  
Peter Dundek ◽  
Ladislav Holík ◽  
Ladislav Hromádko ◽  
Tomáš Rohlík ◽  
Valerie Vranová ◽  
...  
Keyword(s):  
Root Exudates ◽  
Plant Root ◽  
Root Exudation ◽  
Polluted Soil ◽  
Water Soluble ◽  
Total Carbon ◽  
Organic Substrates ◽  
Qualitative Composition ◽  
Soil Decontamination ◽  
Catabolic Potential

This work presents a summary of literature dealing with the use of plant root exudates in bioremediations. Bioremediation using plants (phytoremediation or rhizoremediation) and associate rhizosphere to decontaminate polluted soil is a method based on the catabolic potential of root-associated microorganisms, which are supported by the organic substrates released from roots. These substrates are called “root exudates”. Root exudates support metabolism of pollutants-decomposing microorganisms in the rhizosphere, and affect sorption / desorption of pollutants. Awareness of exudation rates is necessary for testing soil decontamination. Commonly, water-soluble root exudates of different plants are studied for their qualitative composition which should be related to total carbon of exuded water-soluble compounds. This paper presents the determined rate of plant root exudation and the amount of root exudates carbon used to form artificial rhizosphere.

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