Utilizing high throughput sequencing to understand the movement of pollen-borne viruses at the agroecological interface

Pollen-mediated virus transmission poses a significant challenge to stone fruit production. Prunus necrotic ringspot virus (PNRSV) is a pollen-borne ilarvirus that can result in orchard decline. Bees carry PNRSV-infected pollen and move along orchard blocks during peach bloom. Since PNRSV was also found in wild Prunus spp. near peach orchards, it is still unclear if bees play a role in virus movement at the wild cherry-cultivated peaches interface. We hypothesized that bees visit peach and wild Prunus spp. and also carry PNRSV during peach bloom. Amplicon sequencing using plant genetic markers (ITS1 and trnL) was conducted to identify plant species, particularly wild Prunus spp., that the bees visited. A total of 43 unique plant genera were detected in bee pollen samples, with Prunus being dominant throughout the peach bloom period. Bees captured within peach orchards had more P. persica (peach) pollen, while those from orchard borders showed more variable pollen composition. Wild Prunus spp., including P. caroliniana and P. serotina, were also detected in bee pollen samples throughout peach bloom. Multiple bee genera, including Andrena, Bombus and Habropoda, carried peach and wild Prunus pollen during early and late bloom periods. The significant association between wild Prunus spp. and PNRSV detection in pollen suggests that wild Prunus species may play a role in PNRSV transmission dynamics in orchard settings. We discuss the potential role of bees and wild Prunus spp. in PNRSV ecology at the agroecological interface, emphasizing the need to manage virus inoculum sources to preserve orchard health.