Comparative analyses of hop- and citrus-associated virome in Brazil and Italy and studies on viroid-induced pathogenesis in hop

• Grant number: 23/07870-2
• Support Opportunities: Regular Research Grants
• Duration: February 01, 2024 - January 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Convênio/Acordo: National Research Council of Italy (CNR)
• Principal Investigator: Marcelo Eiras
• Grantee: Marcelo Eiras
• Principal researcher abroad: Francesco Di Serio
• Institution abroad: Consiglio Nazionale delle Ricerche (CNR), Italy
• Host Institution: Instituto Biológico (IB). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). São Paulo , SP, Brazil
• Associated researchers: Alexandre Levi Rodrigues Chaves ; Fabio Nascimento da Silva ; Ricardo Harakava ; Valdenice Moreira Novelli
• Associated scholarship(s): 24/07253-6 - Identification and characterization of viroids in hops in Brazil, BP.TT

Abstract

Brazil is currently the third largest beer producer in the world, with an annual production of more than 15 million liters, and an annual revenue of more than US$ 25 billion. However, Brazil still imports almost all hops (Humulus lupulus, Cannabaceae) used in beer production, mainly from the United States and Germany. In Italy, hop is also prevalently imported from Germany. However, likely due to the increase of craft breweries, the interest for internal production is growing up in both countries, as testified by the surface invested in hop in Brazil and Italy that increased significantly in the last years. 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 to these viroids, hop latent viroid (HLVd, Cocadviroid), a prevalent symptomless pathogen in hop yards worldwide, can lead to reductions in the levels of ±-bitter acid and essential oils in hop cones, with significant reductions in its market value. HLVd has been reported at high incidences in most countries where hops are grown in Europe, Asia, North America, Australia and New Zealand. 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, with most varieties still not completely adapted to the climatic conditions of the different Brazilian regions where hops are grown. Recently, the Instituto Biológico Group reported the first occurrence of HLVd and CBCVd in commercial hop crops in three Brazilian states: Minas Gerais, Paraná and São Paulo. The recent detection of these viroids in Brazil sparked 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 Italy, 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 modern molecular tools, including 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); (ii) to further characterize novel viruses and viroids identified by the metatranscriptomics survey to determine their complete genome and molecular features; (iii) to study biological and molecular aspects involved in the pathogenesis of CBCVd by identifying host mRNAs potentially targeted for RNA silencing-mediated degradation by CBCVd-derived sRNAs; and (iv) to achieve internationalization of the research carried out at Instituto Biológico, with the collaboration of Dr. Francesco Di Serio, CNR, Italy, who leads one of the top research groups studying plant viruses and viroids, with a major focus on understanding virus- and viroid-host interactions, developing diagnostic tools, and managing and controlling pests and diseases, with strong expertise in risk assessment. The development of this project, in addition to advances in the knowledge of the diversity of viruses and viroids that infect hops and citrus in Brazil and Italy, brings the possibility of adding new lines of research in the group led by Dr. Eiras, and new collaborative projects, including, in the future, the departure of graduate students to develop studies in the CNR, Italy, under the supervision of Dr. Di Serio. (AU)