Consequences of agricultural advances on soil and maize microbiomes

Raglin, Sierra Summer

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https://hdl.handle.net/2142/120404 Copy

Description

Title

Consequences of agricultural advances on soil and maize microbiomes

Author(s)

Raglin, Sierra Summer

Issue Date

2023-04-24

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

Kent, Angela D

Doctoral Committee Chair(s)

Yang, Wendy

Committee Member(s)

• Ngumbi, Esther N
• Marshall-Colon, Amy
• Heath, Katy

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Maize
• Zea Mays
• Microbiome
• Rhizosphere
• Nitrification
• Herbivory
• Herbivore-induced Volatile Compounds
• Nitrogen
• Nitrification Suppression
• Plant Growth-promoting

Language

eng

Abstract

Soil microorganisms drive agroecosystems sustainability through soil stabilization, nutrient provisioning, and multi-trophic interactions which alter pathogen and pest resistance. However, agricultural advances directly manipulate soil microbiomes by modifying nutrient ecology with the addition of industrial nitrogen fertilizers, temporally changing soil health. Indirectly, agricultural management influences soil microbiomes by plant species, diverging the rhizosphere microbiome across cultivars within a species due to domestication and breeding. Therefore, this dissertation seeks to understand direct and indirect manipulation of soil microbiomes by exploring management-driven changes in soil nitrogen cycling microbiota, as well as microbe-maize-pest multitrophic interactions important for minimizing pest damage. Long-term changes in nitrogen fertilization, both inorganic and organic, alter nitrification potential due to changes in nitrogen availability, as well as the physiochemical characteristics of soil important for nitrifying activity. Breeding of maize within these fertilized systems alters the selective environment, causing a decrease in maize nitrogen-acquisition symbioses, seen as a reduction of rhizosphere nitrification inhibition throughout maize’s breeding history. Breeding may have altered the multi-trophic interactions between microbes-plants-herbivore through the manipulation of herbivore-induced volatile compounds. Jasmonic acid and terpenoid volatiles were altered throughout maize’s breeding history, potentially due to selection for aboveground architecture. Moreover, this resulted in an enrichment of endophytic Rhodocyclaceae within modern varieties, potentially due to changes in polyunsaturated fatty acid contents in maize roots. Unfortunately, managing the rhizosphere microbiome for enhanced volatile production is highly variable, due to genotype-specific dynamics in both volatile compound and root microbiome composition. Bacillus altitudinus, plant-growth-promoting rhizobacteria had minimal effect on HIPV composition and abundance, suggesting not all rhizobacteria interact with the plant volatilome. Transitioning industrial systems to low-input systems that minimize the adverse effects of agriculture on environmental health requires understanding how microbiomes are manipulated through industrial practices and should identify microbiome-associated phenotypes that can be leveraged to maximize agricultural sustainability and reduce the reliance on synthetic additives.

Graduation Semester

2023-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/120404

Copyright and License Information

Copyright 2023, Sierra Summer Raglin

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