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Use of Quantitative Real-Time PCR to Unravel Ecological Complexity in a Biological Control System

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DOI: 10.4236/abb.2015.64023    2,703 Downloads   3,156 Views   Citations

ABSTRACT

Biological control of soilborne plant pathogens using beneficial fungi, such as the mycoparasite Trichoderma harzianum, offers the prospect of environmentally benign pest control. However, biocontrol organisms have their own natural enemies; for example the fungivorous nematode Aphelenchoides saprophilus preys on T. harzianum. A trophic cascade occurs when three or more trophic levels are present in a food chain, and consumption of the intermediate species affects biomass or productivity of a lower trophic level; such an interaction in this system might reduce the biocontrol efficacy of T. harzianum. However, the presence of refuges, where intermediate-level species are protected from predation, may reduce the ecological impact of a trophic cascade. Interactions among microscopic organisms in a complex medium such as soil are difficult to observe and quantify. We evaluated the potential of quantitative real-time PCR (qRT-PCR) as a tool to investigate the trophic cascade interaction among T. harzianum, A. saprophilus, and the plant pathogen Sclerotinia sclerotiorum. Results indicate that the mycoparasite colonized and persisted inside structures (sclerotia) of the target plant pathogen, where it was relatively protected from predation compared to the surrounding soil environment. In this way, colonization of sclerotia may provide a refuge that reduces trophic cascade effects in this system. qRT-PCR provided a sensitive method to investigate fungal dynamics over time in this multitrophic system.

Conflicts of Interest

The authors declare no conflicts of interest.

Cite this paper

Knudsen, G. , Kim, T. , Bae, Y. and Dandurand, L. (2015) Use of Quantitative Real-Time PCR to Unravel Ecological Complexity in a Biological Control System. Advances in Bioscience and Biotechnology, 6, 237-244. doi: 10.4236/abb.2015.64023.

References

[1] Harman, G.E., Petzoldt, R., Comis, A. and Chen, J. (2004) Interactions between Trichoderma harzianum Strain T22 and Maize Inbred Line Mo17 and Effects of These Interactions on Diseases Caused by Pythiuin ultimum and Colletotrichum graminicola. Phytopathology, 94, 147-153.
http://dx.doi.org/10.1094/PHYTO.2004.94.2.147
[2] Vasas, V. and Jordan, F. (2006) Topological Keystone Species in Ecological Interaction Networks: Considering Link Quality and Nontrophic Effects. Ecological Modelling, 196, 365-378.
http://dx.doi.org/10.1016/j.ecolmodel.2006.02.024
[3] Harman, G.E., Howell, C.R., Viterbo, A., Chet, I. and Lorito, M. (2004) Trichoderma Species—Opportunistic, Avirulent Plant symbionts. Nature Reviews Microbiology, 2, 43-56.
http://dx.doi.org/10.1038/nrmicro797
[4] Knudsen, G.R., Eschen, D.J., Dandurand, L.M. and Bin, L. (1991) Potential for Control of Sclerotinia sclerotiorum through Colonization of Sclerotia by Trichoderma harzianum. Plant Disease, 75, 466-470.
[5] Knudsen, G.R., Eschen, D.J., Dandurand, L.M. and Wang, Z.G. (1991) Method to Enhance Growth and Sporulation of Pelletized Biocontrol Fungi. Applied and Environmental Microbiology, 57, 2864-2867.
[6] Bae, Y.-S. and Knudsen, G.R. (2001) Influence of a Fungus-Feeding Nematode on Growth and Biocontrol Efficacy of Trichoderma harzianum. Phytopathology, 91, 301-306.
http://dx.doi.org/10.1094/PHYTO.2001.91.3.301
[7] Wardle, D.A., Williamson, W.M., Yeates, G.W. and Bonner, K.I. (2005) Trickledown Effects of Aboveground Trophic Cascades on the Soil Food Web. Oikos, 111, 348-358.
http://dx.doi.org/10.1111/j.0030-1299.2005.14092.x
[8] Pace, M.L., Cole, J.J., Carpenter, S.R. and Kitchell, J.F. (1999) Trophic Cascades Revealed in Diverse Ecosystems. Trends in Ecology & Evolution, 14, 483-488.
http://dx.doi.org/10.1016/S0169-5347(99)01723-1
[9] Bae, Y.S. and Knudsen, G.R. (2000) Cotransformation of Trichoderma harzianum with β-Glucuronidase and Green Fluorescent Protein Genes Provides a Useful Tool for Monitoring Fungal Growth and Activity in Natural Soils. Applied and Environmental Microbiology, 66, 810-815.
http://dx.doi.org/10.1128/AEM.66.2.810-815.2000
[10] Kim, T.G. and Knudsen, G.R. (2008) Quantitative Real-Time PCR Effectively Detects and Quantifies Colonization of Sclerotia of Sclerotinia sclerotiorum by Trichoderma spp. Applied Soil Ecology, 40, 100-108.
http://dx.doi.org/10.1016/j.apsoil.2008.03.013
[11] Orr, K.A. and Knudsen, G.R. (2004) Use of Green Fluorescent Protein and Image Analysis to Quantify Proliferation of Trichoderma harzianum in Nonsterile Soil. Phytopathology, 94, 1383-1389.
http://dx.doi.org/10.1094/PHYTO.2004.94.12.1383
[12] Sarrocco, S., Mikkelsen, L., Vergara, M., Jensen, D.F., Lubeck, M. and Vannacci, G. (2006) Histopathological Studies of Sclerotia of Phytopathogenic Fungi Parasitized by a GFP Transformed Trichoderma virens Antagonistic Strain. Mycological Research, 110, 179-187.
http://dx.doi.org/10.1016/j.mycres.2005.08.005
[13] Stewart, A. and Harrison, Y. (1988) Mycoparasitism of sclerotia of Sclerotium cepivorum. Australasian Plant Pathology, 18, 10-14.
http://dx.doi.org/10.1071/APP9890010
[14] Fierer, N., Jackson, J.A., Vilgalys, R., and Jackson, R.B. (2005) Assessment of Soil Microbial Community Structure by Use of Taxon-Specific Quantitative PCR Assays. Applied and Environmental Microbiology, 71, 1429-1432.
http://dx.doi.org/10.1128/AEM.71.7.4117-4120.2005
[15] Kabir, S., Rajendran, N., Amemiya, T. and Itoh, K. (2003) Quantitative Measurement of Fungal DNA Extracted by Three Different Methods Using Real-Time Polymerase Chain Reaction. Journal of Bioscience and Bioengineering, 96, 337-343.
http://dx.doi.org/10.1016/S1389-1723(03)90133-2
[16] Kim, T.G. and Knudsen, G.R. (2011) Comparison of Real-Time PCR and Microscopy to Evaluate Sclerotial Colonisation by a Biocontrol Fungus. Fungal Biology, 115, 317-325.
http://dx.doi.org/10.1016/j.funbio.2010.12.008
[17] Hawkins, B.A., Thomas, M.B. and Hochberg, M.E. (1993) Refuge Theory and Biological Control. Science, 262, 1429-1432.
http://dx.doi.org/10.1126/science.262.5138.1429

  
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