Mycovirus genetic diversity; Infection dynamics; Plant pathogen; Hyperparasitsm; Biological control
Ježić Marin, Kolp Matthew, Prospero Simone, Sotirovski Kiril, Double Mark, Rigling Daniel, Risteski Mihajlo, Karin-Kujundžić Valentina, Idžojtić Marilena, Poljak Igor, Ćurković-Perica Mirna (2019), Diversity of Cryphonectria parasitica in callused chestnut blight cankers on European and American chestnut, in Forest Pathology
, 49(6), e12566-e12566.
Introduced pests and pathogens are increasingly challenging agricultural and forest production systems, as well as natural and near-natural ecosystems. Biological control of these harmful organisms is a highly desirable plant protection measure, particularly in forests where the use of pesticides is often not applicable and resistance breeding only a long-term option. Hyperparasitism, the fundamental relationship between two parasitic organisms typically provides the basis for biological control. Mycoviruses that infect plant pathogenic fungi have the potential to be used as biocontrol agents. In this project, we will use the Cryphonectria parasitica-hypovirus pathosystem to investigate the dynamics of virus infection in a fungal pathogen. Cryphonectria parasitica is the causal agent of chestnut blight, an introduced disease of sweet chestnut, which is responsible for a widespread decline of chestnut forests across Europe. Cryphonectria hypovirus 1 (CHV-1) is an RNA virus that infects C. parasitica and acts as biological control agent of chestnut blight. RNA viruses are known to evolve at high rates because of the error-prone viral RNA polymerases, which produce mutants with each replication cycle. As a result, a diverse virus population, referred to as a viral quasispecies, exists in infected hosts. We will use next-generation-sequencing to investigate the quasispecies diversity and infection dynamics of CHV-1 in its fungal host C. parasitica. In the first part of the project, we will establish the methodology to measure quasispecies diversity in CHV-1. The selected method will then be used to analyse viral diversity in field populations of C. parasitica sampled in Croatia and Switzerland. In the second part, we will investigate the quasispecies dynamics during the infection cycle of CHV-1. We hypothesize that the quasispecies diversity will experience bottleneck effects during vertical (into spores) and horizontal (to other fungal host individuals) virus transmission, while it will increase over time during vegetative growth of the fungal host. In the third part, we will assess how quasispecies diversity and composition affect host phenotypes including virulence. Finally, our long-term experiment of monitoring the natural dynamics of CHV-1 infection in C. parasitica populations in chestnut forests will continue. For this, we will resample the experimental sites in Croatia and Switzerland and determine the relationship between CHV-1 infection and canker healing. This project will produce novel knowledge about viruses that infect fungal pathogens and will support biological control of an important plant disease. The project will also be a continuation of a well-established, scientifically fruitful partnership between the Swiss and Croatian research groups.