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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #403863
Research Project: Disease Management and Improved Detection Systems for Control of Pathogens of Vegetables and Strawberries

Location: Crop Improvement and Protection Research

Title: Revisiting the host range of Macrophomina phaseolina

Author
item PENNERMAN, KAYLA - Oak Ridge Institute For Science And Education (ORISE)
item DILLA-ERMITA, JADE - University Of California
item Henry, Peter

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/26/2023
Publication Date: 8/12/2023
Citation: Pennerman, K., Dilla-Ermita, J., Henry, P.M. 2023. Revisiting the host range of Macrophomina phaseolina. American Phytopathological Society Annual Meeting, August 12-16, 2023, Denver, Colorado.

Interpretive Summary:

Technical Abstract: Macrophomina phaseolina is a plant pathogenic fungus that is frequently described as having a broad host range encompassing more than 500 species. We noticed that citations provided in support of this statement did not actually demonstrate such a broad host range. To elucidate the true, documented host range of this fungus, we initiated a literature review of 872 articles published on M. phaseolina since 1913. We discovered the first host range summaries did not require Koch’s postulates or other experimental demonstrations of pathogenicity. Most of the available early host claims were based on tenuous associations between the fungus and symptoms, sometimes without reporting isolation or morphological examination in vitro. These statements apparently led to a pattern of increasingly exaggerated host range claims without support from a primary reference, until the claim that M. phaseolina has 500 hosts became common in the mid 2000’s. At present, the scientific community typically requires Koch’s postulates to characterize pathogenicity on a new host. Among all the available literature, we only discovered primary experimental evidence for M. phaseolina’s pathogenicity on 99 hosts; 71 hosts confirmed by Koch’s postulates and 25 hosts with all steps from Koch’s postulates except recovery of the pathogen from symptomatic tissues. This review demonstrates how scientific concepts can change over time and necessitate changes to historic axioms. We propose that the hyperbole surrounding M. phaseolina’s host range has obscured an accurate depiction of its biology.