Molecular mechanisms of defense by rhizobacteria against root disease.

Cook, Robert; Thomashow, Linda S.; Weller, David M.; Fujimoto, D. K.; Mazzola, Mark; Bangera, Gita; Kim, Dal-Soo

doi:10.1073/pnas.92.10.4197

Cited by 359 publications

(220 citation statements)

References 25 publications

Supporting

Mentioning

214

Contrasting

Unclassified

Order By: Relevance

“…Often, antagonistic microorganisms can produce a range of different antimicrobial secondary metabolites, e.g. 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin, pyoluteorin, phenazines, cyclic lipopeptides and hydrogen cyanide in the case of certain fluorescent pseudomonads (Raaijmakers et al , 2006Picard and Bosco 2008;Cook et al 1995;Weller 2007). Antimicrobial secondary metabolites are also involved in antagonistic effects of fungi such as Trichoderma and Gliocladium (Kubicek et al 2001).…”

Section: Interactions Between Beneficial Microorganisms and Soilbornementioning

confidence: 99%

The rhizosphere: a playground and battlefield for soilborne pathogens and beneficial microorganisms

et al. 2008

View full text Add to dashboard Cite

The rhizosphere is a hot spot of microbial interactions as exudates released by plant roots are a main food source for microorganisms and a driving force of their population density and activities. The rhizosphere harbors many organisms that have a neutral effect on the plant, but also attracts organisms that exert deleterious or beneficial effects on the plant. Microorganisms that adversely affect plant growth and health are the pathogenic fungi, oomycetes, bacteria and nematodes. Most of the soilborne pathogens are adapted to grow and survive in the bulk soil, but the rhizosphere is the playground and infection court where the pathogen establishes a parasitic relationship with the plant. The rhizosphere is also a battlefield where the complex rhizosphere community, both microflora and microfauna, interact with pathogens and influence the outcome of pathogen infection. A wide range of microorganisms are beneficial to the plant and include nitrogen-fixing bacteria, endo-and ectomycorrhizal fungi, and plant growth-promoting bacteria and fungi. This review focuses on the population dynamics and activity of soilborne pathogens and beneficial microorganisms. Specific attention is given to mechanisms involved in the tripartite interactions between beneficial microorganisms, pathogens and the plant. We also discuss how agricultural practices affect pathogen and antagonist populations and how these practices can be adopted to promote plant growth and health.

show abstract

Section: Interactions Between Beneficial Microorganisms and Soilbornementioning

confidence: 99%

The rhizosphere: a playground and battlefield for soilborne pathogens and beneficial microorganisms

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Cook et al (34) suggested the absence of useful genes in wheat and wheat relatives for resistance to take-all could be due to the protection afforded by the DAPG-producing rhizobacteria enriched by wheat monoculture, thereby relieving selection pressure on the host for evolution of resistance such as has occurred with foliar pathogens. Although rhizobacteria responsible for suppression of root diseases represent another genetic resource for use in breeding crop plants for enhanced resistance to pathogens, their management through the cropping system, e.g., crop monoculture, or their introduction with seeds or other the planting material (35) currently represents the best options for maximizing their benefits.…”

Section: Take-all Decline: An Isolated Phenomenon or Source Of Clues mentioning

confidence: 99%

Toward cropping systems that enhance productivity and sustainability

2006

Proc. Natl. Acad. Sci. U.S.A.

134

View full text Add to dashboard Cite

The defining features of any cropping system are (i) the crop rotation and (ii) the kind or intensity of tillage. The trend worldwide starting in the late 20th century has been (i) to specialize competitively in the production of two, three, a single, or closely related crops such as different market classes of wheat and barley, and (ii) to use direct seeding, also known as no-till, to cut costs and save soil, time, and fuel. The availability of glyphosate-and insect-resistant varieties of soybeans, corn, cotton, and canola has helped greatly to address weed and insect pest pressures favored by direct seeding these crops. However, little has been done through genetics and breeding to address diseases caused by residue-and soil-inhabiting pathogens that remain major obstacles to wider adoption of these potentially more productive and sustainable systems. Instead, the gains have been due largely to innovations in management, including enhancement of root defense by antibiotic-producing rhizosphere-inhabiting bacteria inhibitory to root pathogens. Historically, new varieties have facilitated wider adoption of new management, and changes in management have facilitated wider adoption of new varieties. Although actual yields may be lower in direct-seed compared with conventional cropping systems, largely due to diseases, the yield potential is higher because of more available water and increases in soil organic matter. Achieving the full production potential of these more-sustainable cropping systems must now await the development of varieties adapted to or resistant to the hazards shown to account for the yield depressions associated with direct seeding.

show abstract

“…Cook et al (1995) postulated that plants have developed an entirely different strategy to defend themselves against soilborne pathogens. This strategy involves the ability of plants to selectively stimulate and support populations of soil and rhizosphere microorganisms that are antagonistic to their pathogens.…”

Section: Introductionmentioning

confidence: 99%

Phenazine antibiotics produced by fluorescent pseudomonads contribute to natural soil suppressiveness to Fusarium wilt

et al. 2009

View full text Add to dashboard Cite

Natural disease-suppressive soils provide an untapped resource for the discovery of novel beneficial microorganisms and traits. For most suppressive soils, however, the consortia of microorganisms and mechanisms involved in pathogen control are unknown. To date, soil suppressiveness to Fusarium wilt disease has been ascribed to carbon and iron competition between pathogenic Fusarium oxysporum and resident non-pathogenic F. oxysporum and fluorescent pseudomonads. In this study, the role of bacterial antibiosis in Fusarium wilt suppressiveness was assessed by comparing the densities, diversity and activity of fluorescent Pseudomonas species producing 2,4-diacetylphloroglucinol (DAPG) (phlD+) or phenazine (phzC+) antibiotics. The frequencies of phlD+ populations were similar in the suppressive and conducive soils but their genotypic diversity differed significantly. However, phlD genotypes from the two soils were equally effective in suppressing Fusarium wilt, either alone or in combination with non-pathogenic F. oxysporum strain Fo47. A mutant deficient in DAPG production provided a similar level of control as its parental strain, suggesting that this antibiotic does not play a major role. In contrast, phzC+ pseudomonads were only detected in the suppressive soil. Representative phzC+ isolates of five distinct genotypes did not suppress Fusarium wilt on their own, but acted synergistically in combination with strain Fo47. This increased level of disease suppression was ascribed to phenazine production as the phenazine-deficient mutant was not effective. These results suggest, for the first time, that redox-active phenazines produced by fluorescent pseudomonads contribute to the natural soil suppressiveness to Fusarium wilt disease and may act in synergy with carbon competition by resident non-pathogenic F. oxysporum.

show abstract

Molecular mechanisms of defense by rhizobacteria against root disease.

Cited by 359 publications

References 25 publications

The rhizosphere: a playground and battlefield for soilborne pathogens and beneficial microorganisms

The rhizosphere: a playground and battlefield for soilborne pathogens and beneficial microorganisms

Toward cropping systems that enhance productivity and sustainability

Phenazine antibiotics produced by fluorescent pseudomonads contribute to natural soil suppressiveness to Fusarium wilt

Contact Info

Product

Resources

About