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Botanical gardens host diverse plant assemblages that provide valuable opportunities to study fungal biodiversity and plant–fungal interactions. Powdery mildews (Erysiphaceae) are common pathogens in these settings, yet little is known about how they co‐occur with culturable fungi present on infected leaves. To document fungi recovered from infected tissue, we surveyed powdery mildew infections at the JC Raulston Arboretum, which is part of North Carolina State University. We identified the powdery mildew species present and the fungi that could be cultured from the infected phyllosphere. Eighteen powdery mildew species representing three genera were documented and confirmed through morphological and molecular methods. Using a dilution‐to‐extinction culturing approach, we recovered 147 isolates corresponding to 57 fungal species across 36 genera. Several genera includingAspergillusandCladosporiumwere repeatedly recovered from powdery mildew‐infected leaves, and six isolates represent potentially novel lineages. Several of these genera have previously been shown to possess biological control potential against powdery mildew. These findings demonstrate that botanical gardens harbor rich, underexplored fungal diversity and that powdery mildew–infected tissues provide access to a broad community of co‐occurring fungi. Our results highlight the potential of culture‐based surveys in botanical gardens to uncover novel fungal taxa and identify candidate biological control agents for powdery mildew management.
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Effects of microclimate on disease prevalence across an urbanization gradient
Abstract Increased temperatures associated with urbanization (the “urban heat island” effect) have been shown to impact a wide range of traits across diverse taxa. At the same time, climatic conditions vary at fine spatial scales within habitats due to factors including shade from shrubs, trees, and built structures. Patches of shade may function as microclimate refugia that allow species to occur in habitats where high temperatures and/or exposure to ultraviolet radiation would otherwise be prohibitive. However, the importance of shaded microhabitats for interactions between species across urbanized landscapes remains poorly understood. Weedy plants and their foliar pathogens are a tractable system for studying how multiple scales of climatic variation influence infection prevalence. Powdery mildew pathogens are particularly well suited to this work, as these fungi can be visibly diagnosed on leaf surfaces. We studied the effects of shaded microclimates on rates of powdery mildew infection onPlantagohost species in (1) “pandemic pivot” surveys in which undergraduate students recorded shade and infection status of thousands of plants along road verges in urban and suburban residential neighborhoods, (2) monthly surveys of plant populations in 22 parks along an urbanization gradient, and (3) a manipulative field experiment directly testing the effects of shade on the growth and transmission of powdery mildew. Together, our field survey results show strong positive effects of shade on mildew infection in wildPlantagopopulations across urban, suburban, and rural habitats. Our experiment suggests that this relationship is causal, where microclimate conditions associated with shade promote pathogen growth. Overall, infection prevalence increased with urbanization despite a negative association between urbanization and tree cover at the landscape scale. These findings highlight the importance of taking microclimate heterogeneity into account when establishing links between macroclimate or land use context and prevalence of disease.
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- Award ID(s):
- 2240087
- PAR ID:
- 10565038
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Ecology
- Volume:
- 105
- Issue:
- 6
- ISSN:
- 0012-9658
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/ecy.4313
