SMOLBnet 2.0: structural studies of key proteins for fungal diseases in cocoa: witch’s broom and moniliasis: developing strategies to control and understand the pathogenicity

Abstract

The cocoa crop is one of the most prominent agro-industrial activities and an important source of sustainable income for developing countries belonging to the tropical region of the world. It is, nonetheless, also susceptible to a whole variety of pests that can cause serious problems for the pod production, such as fungi, insects, viruses and others. In fact, up to 30 % of world's production is compromised mostly through fungal diseases, such as the Witch' s broom and Moniliasis. The first has been considered the central cocoa pathology in Brazil since its first outbreak in the Bahia state in 1989, resulting in a decrease of about 65 % in the annual production until 2005 and forcing the import of the pods in order to suffice the country's demands. In recent years, a big effort has been put towards the understanding the infection process and the life-cycle of Moniliopthora perniciosa, the causing agent of Witch's broom, beginning by its genome sequencing, led by Dr. Gonçalo Pereira, from the Laboratory of Genomics and Expression, at Unicamp. As a result, several proteins have been identified as key components of the plant-pathogen interaction and most of them are currently undergoing functional and biochemical validation. Alongside, his group has been studying another pathogen from the same genus, the M. roreri, which causes the frosty pod rot (or Moniliasis) in Central America. This is strategically important, since M. roreri has already been reported in border countries and it is considered an inevitable threat to Brazilian cocoa crops. Under this context, we propose a broad collaborative and complementary study, now from the structural biology's point-of-view, of these key fungal proteins, by making use of X-ray crystallography and nuclear magnetic resonance. The selected proteins are representative of four major families, known as the NEPs (Necrosis and Ethylene inducing Peptide), CPs (Ceratoplatanins), TLP (Thaumatins) and PR1 (Pathogen-Related Proteins), plus the alternative oxidase from M. perniciosa. As an outcome of this work we foresee the use of accumulated knowledge in the search for biologically active small molecules that can regulate the target's function as well as the disease process. (AU)