Abstract Detail


Fetters, Andrea [1], Cantalupo, Paul [2], Wei, Na [3], Saenz Robles, Maria Teresa [1], Stephens, Jessica [4], Pipas, James [1], Ashman, Tia-Lynn [1].

The pollen virome revealed: interactions with pollinators and proximity to human disturbances shape the pollen virome of wild plants.

Plant viruses threaten plant biodiversity and food security. Thus, understanding the ways in which they can spread is critical, especially since viral spillover and spillback between wild plant populations and agricultural crops can occur. Pollen is a unique, relatively understudied vehicle for virus spread. Pollen-associated viruses “hitchhike” on or are within pollen grains and are carried directly to new plant hosts by pollinating insects, sometimes over a few kilometers. While foraging for floral resources, pollinators can deposit infected pollen on the most vulnerable part of the plant—the stigma. Thus, pollen-associated viruses have a direct pathway into the maternal plant interior, as well as the embryo after fertilization with infected pollen. To uncover the diversity of viruses that spread via pollen, and to understand landscape features and floral traits that might drive pollen-mediated viral spread, we performed a metagenomic survey of pollen from 24 wild plant species spanning 16 families (five subclasses). Pollen was collected from four geographic regions in the United States that vary in their proximity to human disturbances. Using a virus discovery pipeline, we identified 24 known viruses, 16 of which are newly pollen associated, and many novel viruses, including nine coding-complete viral genomes, as pollen-associated. Over half of those belong to the Bromoviridae, Partitiviridae, and Secoviridae viral families, but many other viral families are also represented, thus greatly expanding the understanding of pollen virome diversity. The data revealed that there were more pollen-associated viruses in wild plants growing in close proximity to agriculture compared to those inhabiting communities that were relatively isolated from human disturbances. When we examined the previously unexplored connection between virus richness and plant traits related to plant-pollinator interactions, we found that wild plants with multiple-flowered inflorescences, bilaterally symmetric flowers, restricted access to floral resources, and smaller, spikier pollen grains harbored more pollen-associated viruses than plants with opposite floral and pollen grain traits. We also found that plants in the Asteridae subclass had more pollen-associated viruses relative to the plants in other subclasses. The observed association of viral diversity and landscape attributes, floral traits, and subclass highlight the need to incorporate pollination as a driver of this unique viral niche, as well as examine how landscape modification provides opportunities for viruses to spread to new host populations.

1 - University of Pittsburgh, Biological Sciences, 4249 Fifth Avenue, Pittsburgh, PA, 15260, USA
2 - University of Pittsburgh, Biomedical Informatics, 5607 Baum Boulevard, Pittsburgh, PA, 15206, USA
3 - Holden Arboretum, 9550 Sperry Rd, Kirtland, OH, 44094, USA
4 - Westfield State University, Biology Department, 577 Western Avenue, Westfield , MA, 01086, USA

floral traits
human disturbance.

Presentation Type: Oral Paper
Session: ECO6, Ecology 6: Reproductive Ecology
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 10:45 AM
Number: ECO6004
Abstract ID:512
Candidate for Awards:Ecological Section Best Graduate Student Paper

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