Project Title

Prevalence and Impacts of a Leaf Spot Disease (Pseudocercosporella sublineolata) on Veratrum viride (Melanthiaceae), False Hellebore

Authors' Affiliations

Leeah Sutton, Department of Biological Sciences, College of Arts and Science, East Tennessee State University, Johnson City, TN. Foster Levy, Department of Biological Sciences, College of Arts and Science, East Tennessee State University, Johnson City, TN.

Location

Culp Room 210

Start Date

4-6-2022 9:45 AM

End Date

4-6-2022 10:00 AM

Faculty Sponsor’s Department

Biological Sciences

Name of Project's Faculty Sponsor

Foster Levy

Additional Sponsors

Dr. Rebecca Pyles, Dr. Gerardo Arceo-Gomez

Classification of First Author

Undergraduate Student

Competition Type

Non-Competitive

Type

Boland Symposium

Project's Category

Ecology

Abstract or Artist's Statement

Infectious fungal diseases pose a substantial threat to susceptible plant species, causing host declines, limiting host populations’ community role, and threatening the sustainability of natural ecosystems. Evaluating disease severity and progression is essential for understanding the impacts of these diseases, and this information could provide insights into developing future interventions. On Roan Mountain, Tennessee, native monocot Veratrum viride (Röhl.), was recently discovered to be infected with a fungal pathogen, Pseudocercosporella sublineolata (Thüm. U. Braun.), a Veratrum-specific leaf spot disease. To understand the prevalence and impacts of this disease, a demographic and disease severity study was performed. We hypothesized that P. sublineolata infection was associated with the decline of leaves and the premature seasonal senescence of V. viride plants, and that the increase in the number of leaf spots over the growing season was associated with the decline in plant health. To test these hypotheses, twenty plants from two different populations on Roan Mountain were systematically selected and tagged for a total of forty plants. From June through September 2021, demographic characteristics (plant height, number of leaves, and whether the plant flowered), and disease data (plant health, number of leaf spots, diameter of spots, and whether spots harbored P. sublineolata spores) were recorded over seven visits. To diagnose the disease, leaf spot samples were collected, slides were prepared and examined for spores at 100/200X magnification. We confirmed the diagnosis of P. sublineolata infection based on the conidia’s shape, size, and number of cells. The relationship between P. sublineolata and plant senescence was strengthened because the samples had abundant conidia that were present as pure isolates rather than a mixture of other potential microbial pathogens. All plants in the study declined progressively throughout the growing season, and they senesced earlier than expected, i.e., before the first frost. This early season decline likely limits reserves stored in the overwintering bulb and inhibits seed maturation, thereby posing a threat to the viability of these V. viride populations on Roan Mountain.

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Apr 6th, 9:45 AM Apr 6th, 10:00 AM

Prevalence and Impacts of a Leaf Spot Disease (Pseudocercosporella sublineolata) on Veratrum viride (Melanthiaceae), False Hellebore

Culp Room 210

Infectious fungal diseases pose a substantial threat to susceptible plant species, causing host declines, limiting host populations’ community role, and threatening the sustainability of natural ecosystems. Evaluating disease severity and progression is essential for understanding the impacts of these diseases, and this information could provide insights into developing future interventions. On Roan Mountain, Tennessee, native monocot Veratrum viride (Röhl.), was recently discovered to be infected with a fungal pathogen, Pseudocercosporella sublineolata (Thüm. U. Braun.), a Veratrum-specific leaf spot disease. To understand the prevalence and impacts of this disease, a demographic and disease severity study was performed. We hypothesized that P. sublineolata infection was associated with the decline of leaves and the premature seasonal senescence of V. viride plants, and that the increase in the number of leaf spots over the growing season was associated with the decline in plant health. To test these hypotheses, twenty plants from two different populations on Roan Mountain were systematically selected and tagged for a total of forty plants. From June through September 2021, demographic characteristics (plant height, number of leaves, and whether the plant flowered), and disease data (plant health, number of leaf spots, diameter of spots, and whether spots harbored P. sublineolata spores) were recorded over seven visits. To diagnose the disease, leaf spot samples were collected, slides were prepared and examined for spores at 100/200X magnification. We confirmed the diagnosis of P. sublineolata infection based on the conidia’s shape, size, and number of cells. The relationship between P. sublineolata and plant senescence was strengthened because the samples had abundant conidia that were present as pure isolates rather than a mixture of other potential microbial pathogens. All plants in the study declined progressively throughout the growing season, and they senesced earlier than expected, i.e., before the first frost. This early season decline likely limits reserves stored in the overwintering bulb and inhibits seed maturation, thereby posing a threat to the viability of these V. viride populations on Roan Mountain.