The pollen virome of wild plants and its association with variation in floral traits and land use

Abstract

Pollen is a unique vehicle for viral spread. Pollen-associated viruses hitchhike on or within pollen grains and are transported to other plants by pollinators. They are deposited on flowers and have a direct pathway into the plant and next generation via seeds. To discover the diversity of pollen-associated viruses and identify contributing landscape and floral features, we perform a species-level metagenomic survey of pollen from wild, visually asymptomatic plants, located in one of four regions in the United States of America varying in land use. We identify many known and novel pollen-associated viruses, half belonging to the Bromoviridae, Partitiviridae, and Secoviridae viral families, but many families are represented. Across the regions, species harbor more viruses when surrounded by less natural and more human-modified environments than the reverse, but we note that other region-level differences may also covary with this. When examining the novel connection between virus richness and floral traits, we find that species with multiple, bilaterally symmetric flowers and smaller, spikier pollen harbored more viruses than those with opposite traits. The association of viral diversity with floral traits highlights the need to incorporate plant-pollinator interactions as a driver of pollen-associated virus transport into the study of plant-viral interactions.

Defining virus-carrier networks that shape the composition of the mosquito core virome of a local ecosystem

“…The viruses of the core virome, as opposed to the viruses that cause acute symptomatic infections, have been characterized in a variety of organisms, including humans ( Haynes and Rohwer 2011 ), animals ( de Brito et al. 2021 ), plants ( Fetters et al. 2022 ), and fungi ( Jia et al.…”

Long term anthropic management and associated loss of plant diversity deeply impact virome richness and composition ofPoaceaecommunities

“…The results have revealed the complex structure of viral communities in nature by combining different ecological analyses (virus richness, network, prevalence, co-infection, spatial distribution and genetic structure). So far, plant virus metagenomics-based studies have focused their ecological analyses on family or genus taxonomic ranks, or examined viral OTUs clustered at a standard level of 90% identity (20, 29, 32, 33). Improving the taxonomic resolution of such studies toward the species level is a crucial point to fine tune ecological analyses such as the estimation of virus(es) genetic structure and diversity (richness and evenness), or even to characterize novel virus species (22).…”

Diversity and pathobiology of an ilarvirus unexpectedly detected in diverse host plants and in global sequencing data

“…Several ilarviruses and other members of family Bromoviridae were shown to be horizontally transmitted through pollen (Gilmer and Way 1960; George and Davidson 1963; Sdoodee and Teakle 1988; Greber et al 1991; Mink 1993; Sdoodee and Teakle 1993; Aparicio et al 1999; Card et al 2007; Kawamura et al 2014; Jaspers et al 2015). In some cases, ilarviruses were also reported to be associated with pollen surfaces or exine (Hamilton 1977; Digiaro and Savino 1992; Fetters et al 2022). The random directionality of transmission through pollen, whether actively or passively with the aid of arthropod vectors (Mink 1993), could result in erroneous assignation of natural host range of a virus, especially if sensitive diagnostic assays, such as HTS, are used.…”