Viroids infecting hops in Brazil: Survey of occurrence, identification, characterization, analysis of viromes and genetic diversity

• Grant number: 25/10995-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2025
• End date: November 30, 2027
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Marcelo Eiras
• Grantee: Keyla Sanai Silva Dias
• Host Institution: Instituto Biológico (IB). Agência Paulista de Tecnologia dos Agronegócios (APTA). São Paulo , SP, Brazil
• Associated research grant: 23/07870-2 - Comparative analyses of hop- and citrus-associated virome in Brazil and Italy and studies on viroid-induced pathogenesis in hop, AP.R

Abstract

Brazil is the third largest beer producer in the world, however, still imports almost all hops (Humulus lupulus, Cannabaceae) used in beer production. Due to the increase of craft breweries, the interest for internal production is growing up in Brazil. Viroids are the major problem in hop production in the EU, initially due to hop stunt viroid (HSVd, Hostuviroid, Pospiviroidae) outbreaks and more recently due to epidemics of citrus bark cracking viroid (CBCVd, Cocadviroid, Pospiviroidae). In addition, hop latent viroid (HLVd, Cocadviroid), a prevalent symptomless pathogen in hop yards worldwide, can lead to reductions in the levels of bitter ¿- and ¿-acids and essential oils in hop cones, with significant reductions in its market value. With the increase in the cultivated area and consequent increase in production, phytosanitary problems began to emerge, mainly because hop is a new crop in Brazil. Recently, the Instituto Biológico Group reported the first occurrence of HLVd and CBCVd in commercial hop crops in Brazil, sparking an alert for hop producers and the other links involved in this agriculture production chain. Specifically in relation to CBCVd, as this viroid is also a citrus pathogen, not yet reported in Brazil, there is a risk of the pathogen "jumping" from hops to citrus (and vice versa). Therefore, the general objective of this project is to advance knowledge on viruses and viroids that infect hops, citrus and associated weeds in Brazil, and on the pathogenesis of CBCVd. This project has the following specific objectives: (i) to carry out a metatrascriptomic survey of viruses and viroids in hop and citrus and in plants associated with these crops, using next generation sequencing (homology-dependent and homology-independent approaches will be used to maximize the identification of known and unknown viruses and viroid-like RNAs); and (ii) to further characterize novel viruses and viroids identified by the metatranscriptomics survey to determine their complete genome and molecular features.