Discovery of a widespread presence bunyavirus that may have symbiont-like relationships with different species of aphids

Abstract

Aphids are important agricultural pests, vectors of many plant viruses and have sophisticated relationships with symbiotic microorganisms. Abundant asymptomatic RNA viruses have been reported in aphids due to the application of RNA-seq, but aphid-virus interactions remain unclear. Bunyavirales is the most abundant RNA virus order, which can infect mammals, arthropods, and plants. However, many bunyaviruses have specific hosts, such as insects. Here, we discovered 18 viruses from 10 aphid species by RNA-seq. Importantly, a widespread presence bunyavirus, Aphid bunyavirus 1 (ABV-1), was determined to have a wide host range, infecting and replicating in all 10 tested aphid species. ABV-1 may be transmitted horizontally during feeding on plant leaves and vertically through reproduction. In a comparison of the physiological parameters of ABV-1^high and ABV-1^low strains of pea aphid, higher ABV-1 titers reduced the total nymphal duration and induced the reproduction. Moreover, viral titer significantly affected the lipid and protein contents in pea aphids. In summary, we proposed that ABV-1 may have stable symbiont-like relationships with aphids, and these observations may provide a new direction for studying bunyaviruses in aphids and establishing a model for virus-aphid interactions.

Keywords: Phasmaviridae; RNA virus; RNAi; insect-specific virus; pea aphid.