1887

Abstract

and are ubiquitous insect pathogens and possible plant symbionts, as some strains are endophytic or colonize the rhizosphere. We evaluated 11 strains of and , and two soil saprophytes (the non-rhizospheric and the rhizosphere-competent ) for their ability to germinate in bean root exudates (REs). Our results showed that some generalist strains of were as good at germinating in RE as , although germination rates of the specialized acridid pathogen and the strains were significantly lower. At RE concentrations of <1 mg ml, strain ARSEF 2575 showed higher germination rates than . Microarrays showed that strain 2575 upregulated 29 genes over a 12 h period in RE. A similar number of genes (21) were downregulated. Upregulated genes were involved in carbohydrate metabolism, lipid metabolism, cofactors and vitamins, energy metabolism, proteolysis, extracellular matrix/cell wall proteins, transport proteins, DNA synthesis, the sexual cycle and stress response. However, 41.3 % of the upregulated genes were hypothetical or orphan sequences, indicating that many previously uncharacterized genes have functions related to saprophytic survival. Genes upregulated in response to RE included the subtilisin Pr1A, which is also involved in pathogenicity to insects. However, the upregulated adhesin specifically mediates adhesion to plant surfaces, demonstrating that has genes for rhizosphere competence that are induced by RE.

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2011-01-01
2019-12-09
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References

  1. Angelini, C., Cutillo, L., De Canditiis, D., Mutarelli, M. & Pensky, M. ( 2008; ). BATS: a Bayesian user-friendly software for Analyzing Time Series microarray experiments. BMC Bioinformatics 9, 415.[CrossRef]
    [Google Scholar]
  2. Bagga, S., Hu, G., Screen, S. E. & St Leger, R. J. ( 2004; ). Reconstructing the diversification of subtilisins in the pathogenic fungus Metarhizium anisopliae. Gene 324, 159–169.[CrossRef]
    [Google Scholar]
  3. Bais, H. P., Weir, T. L., Perry, L. G., Gilroy, S. & Vivanco, J. M. ( 2006; ). The role of root exudates in rhizosphere interactions with plants and other organisms. Annu Rev Plant Biol 57, 233–266.[CrossRef]
    [Google Scholar]
  4. Bidochka, M. J., Kasperski, J. E. & Wild, G. A. M. ( 1998; ). Occurrence of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana in soils from temperate and near-northern habitats. Can J Bot-Rev Can Bot 76, 1198–1204.[CrossRef]
    [Google Scholar]
  5. Bidochka, M. J., Kamp, A. M., Lavender, T. M., Dekoning, J. & De Croos, J. N. A. ( 2001; ). Habitat association in two genetic groups of the insect-pathogenic fungus Metarhizium anisopliae: uncovering cryptic species? Appl Environ Microbiol 67, 1335–1342.[CrossRef]
    [Google Scholar]
  6. Freimoser, F. M., Screen, S., Bagga, S., Hu, G. & St Leger, R. J. ( 2003; ). Expressed sequence tag (EST) analysis of two subspecies of Metarhizium anisopliae reveals a plethora of secreted proteins with potential activity in insect hosts. Microbiology 149, 239–247.[CrossRef]
    [Google Scholar]
  7. Hale, M. G., Moore, L. D. & Griffin, G. J. ( 1978; ). Root exudates and exudation. In Interactions between Non-Pathogenic Soil Microorganisms and Plants, p. 475. Edited by Dommergues, Y. R. & Krupa, S. V.. Amsterdam. : Elsevier Scientific Publishing Company.
    [Google Scholar]
  8. Han, K. H., Kim, J. H., Moon, H., Kim, S., Lee, S. S., Han, D. M., Jahng, K. Y. & Chae, K. S. ( 2008; ). The Aspergillus nidulans esdC (early sexual development) gene is necessary for sexual development and is controlled by veA and a heterotrimeric G protein. Fungal Genet Biol 45, 310–318.[CrossRef]
    [Google Scholar]
  9. Harman, G. E. ( 2006; ). Overview of mechanisms and uses of Trichoderma spp. Phytopathology 96, 190–194.[CrossRef]
    [Google Scholar]
  10. Harman, G. E. & Shoresh, M. ( 2007; ). The mechanisms and applications of symbiotic opportunistic plant symbionts. In Novel Biotechnologies for Biocontrol Agent Enhancement and Management, p. 374. Edited by Vurro, M. & Gressel, J.. Dordrecht, The Netherlands. : Springer.
    [Google Scholar]
  11. Hu, G. & St. Leger, R. J. ( 2002; ). Field studies using a recombinant mycoinsecticide (Metarhizium anisopliae) reveal that it is rhizosphere competent. Appl Environ Microbiol 68, 6383–6387.[CrossRef]
    [Google Scholar]
  12. Kerry, B. R. ( 2000; ). Rhizosphere interactions and the exploitation of microbial agents for the biological control of plant-parasitic nematodes. Annu Rev Phytopathol 38, 423–441.[CrossRef]
    [Google Scholar]
  13. Milner, R. J. ( 1992; ). Selection and characterization of strains of Metarhizium anisopliae for control of soil insects in Australia. In Biological Control of Locusts and Grasshoppers, pp. 200–207. Edited by Lomer, C. J. & Prior, C.. Wallingford, UK. : CAB International; International Institute of Tropical Agriculture.
    [Google Scholar]
  14. O'Brien, T. R. ( 2008; ). Metarhizium anisopliae's persistence as a saprophyte, genetic basis of adaptation and role as a plant symbiont. PhD thesis, University of Maryland.
  15. Pingel, R. L. & Lewis, L. C. ( 1996; ). The fungus Beauveria bassiana (Balsamo) Vuillemin in a corn ecosystem: its effect on the insect predator Coleomegilla maculata De Geer. Biol Control 6, 137–141.[CrossRef]
    [Google Scholar]
  16. Prior, C. ( 1992; ). Discovery and characterization of fungal pathogens for locust and grasshopper control. In Biological Control of Locusts and Grasshoppers, pp. 159–180. Edited by Lomer, C. J. & Prior, C.. Wallingford, UK. : CAB International.
    [Google Scholar]
  17. Quesada-Moraga, E., Navas-Cortés, J. A., Maranhao, E. A. A., Ortiz-Urquiza, A. & Santiago-Álvarez, C. ( 2007; ). Factors affecting the occurrence and distribution of entomopathogenic fungi in natural and cultivated soils. Mycol Res 111, 947–966.[CrossRef]
    [Google Scholar]
  18. Rovira, A. D. ( 1965; ). Plant root exudates and their influence upon soil microorganisms. In Ecology of Soil-Borne Plant Pathogens, Prelude to Biological Control, pp. 571. Edited by K. F. Baker, W. C. Snyder, R. R. Baker & others. Los Angeles: University of California Press.
  19. SAS Institute Inc ( 2006; ). SAS/Procedures guide version SAS® 9.1.3. Cary, NC, USA. : SAS Institute, Inc.
    [Google Scholar]
  20. St. Leger, R. J. ( 2007; ). Metarhizium anisopliae as a model for studying bioinsecticidal host pathogen interactions. In Novel Biotechnologies for Biocontrol Agent Enhancement and Management, pp. 179–204. Edited by Vurro, M. & Gressel, J.. New York/Heidelberg. : Springer.
    [Google Scholar]
  21. St. Leger, R. J. ( 2008; ). Studies on adaptations of Metarhizium anisopliae to life in the soil. J Invertebr Pathol 98, 271–276.[CrossRef]
    [Google Scholar]
  22. Wagner, B. L. & Lewis, L. C. ( 2000; ). Colonization of corn, Zea mays, by the entomopathogenic fungus Beauveria bassiana. Appl Environ Microbiol 66, 3468–3473.[CrossRef]
    [Google Scholar]
  23. Wang, C. S. & St. Leger, R. J. ( 2007; ). The MAD1 adhesin of Metarhizium anisopliae links adhesion with blastospore production and virulence to insects, and the MAD2 adhesin enables attachment to plants. Eukaryot Cell 6, 808–816.[CrossRef]
    [Google Scholar]
  24. Wang, C. S., Hu, G. & St. Leger, R. J. ( 2005; ). Differential gene expression by Metarhizium anisopliae growing in root exudate and host (Manduca sexta) cuticle or hemolymph reveals mechanisms of physiological adaptation. Fungal Genet Biol 42, 704–718.[CrossRef]
    [Google Scholar]
  25. Wang, S. B., Leclerque, A., Pava-Ripoll, M., Fang, W. G. & St. Leger, R. J. ( 2009; ). Comparative genomics using microarrays reveals divergence and loss of virulence associated genes in host-specific strains of the insect pathogen Metarhizium anisopliae. Eukaryot Cell 8, 888–898.[CrossRef]
    [Google Scholar]
  26. Wolfger, H., Mamnun, Y. M. & Kuchler, K. ( 2001; ). Fungal ABC proteins: pleiotropic drug resistance, stress response and cellular detoxification. Res Microbiol 152, 375–389.[CrossRef]
    [Google Scholar]
  27. Woo, S. L., Scala, F., Ruocco, M. & Lorito, M. ( 2006; ). The molecular biology of the interactions between Trichoderma spp., phytopathogenic fungi, and plants. Phytopathology 96, 181–185.[CrossRef]
    [Google Scholar]
  28. Zimmermann, G. ( 2007; ). Review on safety of the entomopathogenic fungus Metarhizium anisopliae. Biocontrol Sci Technol 17, 879–920.[CrossRef]
    [Google Scholar]
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List of taxa used in this study [PDF](9 KB)

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log expression ration (IB/IA) of the 50 differentially expressed genes of the entomopathogenic fungus 2575 while growing on root exudates during a time-course [PDF](41 KB)

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