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Concurrent Session

Session: Concurrent Session: Management of diseases and emerging diseases

Effects of increasing atmospheric carbon dioxide levels on soybean responses to diverse pathogens

Monday, July 14, 2025
16:25 - 16:35  
Location: Room P+Q

    Presenting Author(s)

  • SW

    Steven A. Whitham

    Department of Plant Pathology, Entomology and Microbiology, Iowa State University
    Ames, Iowa, United States

    • Author(s)

  • MB

    Melissa Bredow

    Department of Plant Pathology, Entomology and Microbiology, Iowa State University
    Ames, Iowa, United States

  • EK

    Ekkachai Khwanbua

    Graduate student
    Department of Plant Pathology, Entomology and Microbiology, Iowa State University
    Ames, Iowa, United States

  • AC

    Aline Chicowski

    Department of Plant Pathology, Entomology and Microbiology, Iowa State University
    Ames, Iowa, United States

  • YQ

    Yunhui Qi

    Department of Data Science, Dana-Farber Cancer Institute
    Boston, Massachusetts, United States

  • MB

    Matthew Breitzman

    Iowa State University
    Ames, Iowa, United States

  • KH

    Katerina Holan

    United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Corn Insects and Crop Genetics Research Unit
    Ames, Iowa, United States

  • PL

    Peng Liu

    Department of Statistics, Iowa State University
    Ames, Iowa, United States

  • MG

    Michelle Graham

    United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Corn Insects and Crop Genetics Research Unit and Department of Agronomy
    Ames, Iowa, United States

Abstract Text:

Elevated atmospheric CO₂ (eCO₂) has complex effects on plant-pathogen interactions, making it difficult to predict how rising CO₂ levels will impact crop disease dynamics. To investigate these effects, we examined disease development and molecular defense responses in soybean grown under ambient (419 ppm) and elevated (550 ppm) CO₂. Plants were challenged with bacterial, viral, fungal, and oomycete pathogens, and we assessed disease severity, pathogen growth, gene expression, and defense mechanisms. Under eCO₂, soybean was less susceptible to Pseudomonas syringae pv. glycinea but more susceptible to bean pod mottle virus, soybean mosaic virus, and Fusarium virguliforme, while susceptibility to Pythium sylvaticum remained unchanged, though greater biomass loss was observed. Reduced susceptibility to bacterial infection correlated with enhanced defense responses, whereas increased viral susceptibility was linked to diminished antiviral defenses. These findings provide key insights into how rising CO₂ levels may reshape soybean-pathogen interactions, underscoring the need to consider microbial threats to both shoots and roots in future climates. Understanding these responses is crucial for developing climate-resilient disease management strategies.