AUXIN QUANTIFICATION IN CACAO AND TOMATO INOCULATED BY Moniliophthora perniciosa THE CAUSAL AGENT OF WITCHES' BROOM DISEASE

• Grant number: 24/11518-5
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: December 16, 2024
• End date: March 15, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Antonio Vargas de Oliveira Figueira
• Grantee: João Vitor de Oliveira Mendes
• Supervisor: Miguel Angel Perez-Amador
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: Universitat Politécnica de Valéncia (UPV), Spain
• Associated to the scholarship: 23/02787-0 - Functional study in tomato on the role of the hormone auxin in the induction of symptoms resulting from infection by Moniliophtora perniciosa, causal agent of witches' broom in cocoa, BP.IC

Abstract

Witches' Broom Disease, caused by the hemibiotrophic basidiomycete Moniliophthora perniciosa, is the most significant disease of cacao (Theobroma cacao) in Brazil. Infection occurs through the penetration of germ tubes originating from basidiospores into meristematic tissues. The main symptoms of the disease are the swelling of infected branches and the pronounced induction of lateral shoots (green brooms). The S-biotype of M. perniciosa, through artificial inoculation, is capable of infecting tomato (Solanum lycopersicum), which presents the main symptoms present in the biotrophic phase of the disease in cocoa. The tomato cultivar 'Micro-Tom' (MT) has a short life cycle, limited size, and ease of genetic transformation and is demonstrated to be a suitable genetic model for studying this unusual interaction. It is known that the production of hormones by some pathogenic fungi promotes hormonal imbalance in the host. In this regard, the production of auxin by M. perniciosa has already been reported. Furthermore, auxin-responsive genes were induced in infected cocoa tree tissues 30 days after infection. The entire and diageotropic (dgt) mutants, both in the MT background, contrasted in auxin signaling, showing high and low responses to auxin, respectively. The inoculation of such mutants and MT with the S-biotype of M. perniciosa suggests that auxin acts in favor of the pathogen. Given such evidence, the main objective of this project will be to compare the results of auxin quantification in cocoa and tomato inoculated, respectively, with biotypes - C and S of M. perniciosa, to add to the results that our group is generating currently and contribute to the understanding of the relevance of auxin during M. perniciosa infection.