First report of citrus bark cracking viroid and hop latent viroid infecting hop in commercial yards in Brazil

Abstract

In Brazil, there has been an increase of more than 100% in the cultivated area of hop (Humulus lupulus), due to the boom in the production of craft beers. We investigated whether viroids affect Brazilian hop production. Ten hop plants of each variety (‘Cascade’, ‘Comet’, ‘Saaz’, ‘Triple’, ‘Zeus’) showing dwarfism and yellowing were collected between May 2020 to October 2021 in commercial hop yards located in Southeast (Minas Gerais, São Paulo) and South (Paraná) Brazil. Total RNA was extracted using Trizol reagent, and RT-PCR was performed with specific primers for citrus bark cracking viroid (CBCVd), hop latent viroid (HLVd) and hop stunt viroid (HSVd) (Jakse et al. 2015). Amplified DNA fragments of 284 and 256 bp were obtained only using primers for CBCVd and HLVd, respectively, and viroids presence was confirmed after sequencing of those PCR products. Slot-blot hybridizations using digoxigenin-labelled DNA probes specific for each viroid were also evaluated and confirmed RT-PCR results.