Pollen transmissibility of Tobacco ringspot virus in Nicotiana spp

A cherry isolate of Tobacco ringspot virus (TRSV) was biologically characterized to document the pollen transmission of this virus. Biological and serological tests combined with electron microscopy, proved the presence of TRSV on the surface and within the pollen grain of Nicotiana tabacum cv. Xanthi. Further evidence to support this association was detection of viral ribonucleic acid in anther and pollen material using reverse transcriptase polymerase chain reaction. Pollen from infected plants was less viable (78%) than that from healthy plants (92%). Cross-pollination between healthy and virus-infected plants suggested that either direct or indirect invasion of embryo could result in seed transmission, although the infected female parent was more effective in transmissibility of the virus. The low incidence of seed transmission of TRSV by infectivity assays of progeny from selfed- and cross-pollinated infected plants was observed when compared using enzyme-linked immunosorbent assay. This may correlate to low titre of virus or non-infectious viral particles in recovered Nepovirus-infected seedlings.