Hop latent viroid (HLVd) microevolution: An experimental transmission of HLVd "thermomutants" to solanaceous species

Abstract

The possibility was examined whether the pool of sequence variants of HLVd which accumulated as progeny of "thermomutants" induced upon heat-treatment of hop could initiate infection of non-host solanaceous plants. It was found that HLVd microevolution led to the appearance of HLVd population in tomato. This viroid population was maintained at levels detectable by molecular hybridisation, showing the highest concentration in apical leaves. HLVd was further transferred from tomato to Nicotiana benthamiana, where distinct HLVd sequence variants appeared and were stably maintained at low levels. Our results show that replication of HLVd under heat stress resulted in the production of viroid quasispecies, potentially important for viroid evolution in so-called non host plants.