Functional analysis of genes related to the immune response of Nicotiana benthamiana during infection by Moniliophthora perniciosa by Virus-Induced Gene Silencing (VIGS)

• Grant number: 25/12655-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Principal Investigator: Antonio Vargas de Oliveira Figueira
• Grantee: Rafaela Marosti dos Santos
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 22/13438-3 - Molecular aspects of the Nicotiana benthamiana infection by Moniliophthora perniciosa as a new model system to investigate the Witches Broom Disease of cacao, AP.R

Abstract

The export of cocoa seeds (Theobroma cacao), a tree species endemic to the Amazon, was once of great economic importance to the Brazilian economy. However, the disease witches' broom, caused by the basidiomycete Moniliophthora perniciosa, has devastated plantations in the country's main producing region in southern Bahia. Both cocoa and M. perniciosa present biological challenges that limit advances in basic and applied research. Therefore, the use of model plants has proven to be an efficient approach to study pathogenesis. The miniature tomato cultivar (Solanum lycopersicum) 'Micro-Tom' and the recently described susceptibility of Nicotiana benthamiana to M. perniciosa offer new opportunities for the study of mechanisms of resistance to infection. Nicotiana benthamiana allows the application of molecular genetic tools, such as virus-induced gene silencing (VIGS), enabling the rapid silencing of specific host target genes of interest. Moniliophthora perniciosa can be classified into several biotypes according to host specificity, with the most studied being the C biotype, which infects T. cacao; the S biotype, which infects Solanaceae; and the L biotype, associated with the infection of lianas of the Bignoniaceae family. Interestingly, isolates of the C and S biotypes (except for the S isolate 'Tiradentes') are capable of infecting N. benthamiana, which allows comparative studies on pathogen-plant compatibility and the associated molecular mechanisms. After establishing the VIGS methodology for the study of the silencing of genes potentially associated with the immune response of N. benthamiana to M. perniciosa infection, we propose to expand the use of this approach to investigate other components of the immune system of the species. Our objective is to identify factors associated with host specificity and, in the future, with resistance to the pathogen. In addition, the incidence of infection in tomato plants genetically modified to express Arabidopsis thaliana immunity receptors will be evaluated, aiming to deepen the understanding of the mechanisms of resistance to M. perniciosa.