Rhizosphere

Abstract

The rhizosphere is that part of the soil ecosystem where plant roots, soil and the soil biota interact with each other. These interactions are often of benefit to plants, improve soil fertility and enhance the degradation of toxic chemicals. Rhizodeposition from plants is the key energy supply for the rhizosphere biota. Mineral nutrients are supplied by the soil matrix, organic residues and biological nitrogen fixation. The interactive biotic community includes microorganisms, protozoa and soil fauna. Some organisms are beneficial whereas others are harmful. Some deleterious organisms can be suppressed in a variety of biological control strategies. The key physical factors governing rhizosphere activity are temperature, water availability, oxygen, pH and soil structure. The rhizosphere has strong influences on agriculture, and the bioremediation of contaminated and degraded land.

Key Concepts:

  • Rhizodeposition from roots generates the energy substrates for rhizosphere organisms.

  • Mineral nutrients are provided by the soil matrix, organic residues and biological nitrogen fixation.

  • Microorganisms interact with protozoa and soil fauna in the rhizosphere.

  • Deleterious organisms can be suppressed by beneficial organisms in biological control.

  • Temperature, water availability, oxygen, pH and soil structure govern biotic activity.

  • The rhizosphere activity can optimise crop production and remediate contaminated and degraded land.

Keywords: roots; soil; microorganisms; biological control; nutrient cycles

Figure 1.

A growing root in soil.

Figure 2.

Factors influencing rhizosphere interactions.

Figure 3.

Bacterial cell on a wheat root surface, surrounded by mucilage (unstructured) and absorbed clay particles. The original resolution of this image is ×50 000.

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References

Bakker PAHM, Lamers MJG, Bakker AW and Marugg PJ (1986) The role of siderophores in potato tuber yield increase by Pseudomonas putida in short rotation of potato. Netherlands Journal of Plant Pathology 92: 249–256.

Bestel‐Corre G, Dumas‐Gaudot E and Gianinazzi S (2004) Proteomics as a tool to monitor plant–microbe endosymbioses in the rhizosphere. Mycorrhiza 14: 1–10.

Chen K and Pachter L (2005) Bioinformatics for whole‐genome shotgun sequencing of microbial communities. PLoS Computer Biology 1(2): e24 doi:10.1371/journal.pcbi.0010024.

Griffiths BS (1994) Microbial feeding nematodes and protozoa in soil: their effects on microbial activity and nitrogen mineralisation in decomposition hotspots and the rhizosphere. Plant and Soil 164: 25–33.

Huang B, North GB and Nobel PS (1993) Soil sheaths, photosynthate distribution to roots, and rhizosphere relations for Opontia ficus‐indica. International Journal of Plant Science 154: 425–443.

Kent AD and Triplett EW (2002) Microbial communities and their interactions in soil and rhizosphere ecosystems. Annual Reviews in Microbiology 56: 211–236.

Kiely PD, Haynes JM, Higgins CH et al. (2006) Exploiting new systems‐based strategies to elucidate plant–bacterial interactions in the rhizosphere. Microbial Ecology 51: 257–266.

Kuikman PJ and van Veen JA (1990) The impact of protozoa on the availability of bacterial nitrogen to plants. Biology and Fertility of Soils 8: 13–18.

Lynch JM and Whipps JM (1990) Substrate flow in the rhizosphere. Plant and Soil 129: 1–10.

Neilands JB and Leong SA (1986) Siderophores in relation to plant growth and disease. Annual Review of Plant Physiology and Plant Molecular Biology 37: 187–208.

O'sullivan DJ and O'Gara F (1992) Traits of fluorescent Pseudomonas vspp. involved in suppression of root pathogens. Microbial Reviews 56: 662–676.

Orchard BJ, Doucette WJ, Chard JK and Bugbee B (2000) Uptake of Trichloroethylene by hybrid poplar trees grown hydroponically in flow‐through growth chambers. Environmental Toxicology and Chemistry 19: 895–903.

Paulitz TC (1991) Effect of Pseudomonas putida on the stimulation of Pythium ultimum by seed volatiles of pea and soybean. Phytopathology 81: 1282–1287.

Phillips DA, Streit WR and Joseph CM (1995) Plant signals to soil microbes: regulators of rhizosphere colonisation. In: Tikhonovich IA, Provorov NA, Romanov VI and Newton WE (eds) Nitrogen Fixation: Fundamentals and Applications, pp. 293–297. Dordrecht, The Netherlands: Kluwer.

Prosser JL (2002) Molecular and functional diversity in soil microorganisms. Plant and Soil 224: 9–17.

Rondon MR, August PR, Bettermann AD et al. (2000) Cloning the soil metagenome: a strategy for accessing the genetic and functional diversity of uncultured microorganisms. Applied and Environmental Microbiology 66: 2541–2547.

Ruizlozano JM and Azcon R (1995) Hyphal contribution to water uptake in mycorrhizal plants as affected by the fungal species and water status. Physiologia Plantarum 95: 472–478.

Singh BK, Millard P, Whiteley AS and Murrell JC (2004) Unravelling rhizosphere‐microbial interactions: opportunities and limitations. Trends in Microbiology 12: 386–393.

Thomashow LS and Weller DM (1988) Role of phenazine antibiotic from Pseudomonas fluorescens in biological control of Gaeumannomyces graminis var tritici. Journal of Bacteriology 170: 3499–3508.

Voisard C, Keel C, Haas D and Defago G (1989) Cyanide production by Pseudomonas fluorescens helps suppress black root rot of tobacco under gnotobiotic conditions. EMBO Journal 8: 351–358.

Weckwerth W (2003) Metabolomics in systems biology. Annual Review of Plant Biology 54: 669–689.

Further Reading

Cook RJ and Baker KF (1983) The Nature and Practice of Biological Control of Plant Pathogens. St Paul: American Phytopathology Society.

Curl EA and Truelove B (1986) The Rhizosphere. Berlin: Springer.

Dixon GR and Tilston EL (eds) (2010) Soil Microbiology and Sustainable Crop Production. Dordrecht: Springer.

Dumas‐Gaudot E, Amiour N, Weidmann S et al. (2004) A technical trick for studying proteomics in parallel to transcriptomics in symbiotic root–fungus interactions. Proteomics 4: 451–453.

Hokanen HMT and Lynch JM (eds) (1995) Biological Control: Benefits and Risks. Cambridge: Cambridge University Press.

Killham K (1994) Soil Ecology. Cambridge: Cambridge University Press.

Lynch JM (1983) Soil Biotechnology: Microbial Factors in Crop Productivity. Oxford: Blackwell.

Lynch JM (1990) The Rhizosphere. Chichester, UK: Wiley.

Paul EA and Clark FE (1996) Soil Microbiology and Biochemistry. San Diego: Academic Press.

Pinton R, Varanini Z and Nannipieri P (eds) (2007) The Rhizosphere. Biochemistry at the Soil Root Interface, 2nd edn. Boca Raton: CRC Press.

Scheper T and Tsao D (eds) (2003) Phytoremediation. Advances in Biochemical Engineering Biotechnology. Berlin: Springer‐Verlag.

Sylvia DM, Fuhrmann JJ, Hartel PG and Zuberer DA (1998) Principles and Applications of Soil Microbiology. Upper Saddle River, NJ: Prentice Hall.

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How to Cite close
Lynch, James M, and de Leij, Frans(May 2012) Rhizosphere. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0000403.pub2]