Plants affect the horizontal transmission of a new densovirus infecting the green peach aphid Myzus persicae by modulating honeydew production

Abstract

AbstractIn a tritrophic context of plant–insect–entomopathogen, plants play important roles in modulating the interaction of insects and their pathogenic viruses. Currently, the influence of plants on the transmission of insect viruses has been mainly studied on baculoviruses and some RNA viruses, whereas the impact of plants on other insect viruses is largely unknown. Here, we identified a new densovirus infecting the green peach aphid Myzus persicae and tested whether and how host plants influence the transmission of the aphid densovirus. The complete single‐stranded DNA genome of the virus, M. persicae densovirus 2, is 5 727 nt and contains inverted terminal repeats. Transcription and phylogenetic analysis indicated that the virus was distinct from other a few identified aphid densoviruses. The virus abundance was detected highly in the intestinal tract of aphids, compared with the lower level of it in other tissues including head, embryo, and epidermis. Cabbage and pepper plants had no obvious effect on the vertical transmission and saliva‐mediated horizontal transmission of the virus. However, the honeydew‐mediated horizontal transmission among aphids highly depended on host plants (65% on cabbages versus 17% on peppers). Although the virus concentration in the honeydew produced by aphids between 2 plants was similar, the honeydew production of the infected aphids reared on peppers was dramatically reduced. Taken together, our results provide evidence that plants influence the horizontal transmission of a new densovirus in an aphid population by modulating honeydew secretion of aphids, suggesting plants may manipulate the spread of an aphid‐pathogenic densovirus in nature.