The application of ecological niche to create multi-strain microbial biocontrols

Price, Gabriel

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https://hdl.handle.net/2142/113857 Copy

Description

Title

The application of ecological niche to create multi-strain microbial biocontrols

Author(s)

Price, Gabriel

Issue Date

2021-11-29

Director of Research (if dissertation) or Advisor (if thesis)

Yannarell, Anthony

Doctoral Committee Chair(s)

Yannarell, Anthony

Committee Member(s)

• Mideros, Santiago
• Dalling, James
• Davis, Adam

Department of Study

School of Integrative Biology

Discipline

Ecol, Evol, Conservation Biol

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• niche overlap
• microbial biocontrol
• Pythium ultimum
• Enterobacter cloacae

Abstract

The use of multi-strain microbial biocontrols to limit damage associated with plant pathogens is a promising solution to promote sustainable agricultural practices. However, this type of application has had limited success in field applications and requires the incorporation of ecological theory to develop effective solutions to ensure their efficacy under realistic conditions as well as expedited approaches for selecting isolates for combinations. This work aims to address these problems by first selecting isolates and comparing phylogenetic-based screening methods to validated metabolic approaches (such as colorimetric microarrays) and then testing whether pair-wise combinations between the biocontrol bacteria Enterobacter cloacae and other competitor isolates could influence the suppression of the plant pathogen Pythium ultimum. This work specifically seeks to test whether phylogenetic methods can be used to predict niche overlap between competitor isolates and whether niche preemption can be applied to enhance the suppressive performance of E. cloacae in pair-wise combinations. Further, this work also seeks to determine if there are any undiscovered chemical-based factors that may be influencing the relationship between the biocontrol E. cloacae and the pathogen P. ultimum. The results of this work indicate that as of now, metabolic-based approaches cannot be abandoned when attempting to select isolates based on niche similarity, but that phylogenetic methods may soon be sufficient for predicing niche overlap for some chemical-based relationships. Further, this work also found that niche preemption is not an appropriate ecological mechanism for enhancing the efficacy of E. cloacae, but that another niche-based mechanism such as niche complementarity may be appropriate. Finally, this work also discovered and verified that the chemicals 4-hydroxybenzoic acid and amygdalin can adversely influence the performance of E. cloacae at suppressing P. ultimum. sporangia germination. These results indicate that niche-based ecology can be effective at enhancing the performance of multi-strain biocontrols, but that care needs to be taken to determine which ecological mechanisms are appropriate for each pathogen-biocontrol system being addressed.

Graduation Semester

2021-12

Type of Resource

Thesis

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http://hdl.handle.net/2142/113857

Copyright and License Information

Copyright 2021 Gabriel Price-Christenson

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