Molecular characterization of strobilurin resistance mechanisms in Moniliophthora perniciosa, the causal agent of the devastating witches' broom disease of cacao

Abstract

Theobroma cacao, the raw material for chocolate production, is one of the most important perennial crops in the world. However, it is seriously affected by severe fungal diseases. Witches' Broom Disease (WBD) is well-regarded as one of the major phytopathological problems that afflict cacao production in the Americas, with devastating consequences to the agro-economy of the affected countries. In Brazil, WBD was introduced into the largest area of cacao production, the state of Bahia, in 1989. That was followed by a severe decrease in cacao production and, within less than a decade, Brazil shifted from being the second largest cacao exporter to a cacao importer. Currently, the major cacao producers in the world are the African countries (e.g. Ivory Coast), which respond to more than two thirds of the global production. Notably, the chocolate industry is a sixty-billion dollars business, and the US is one of the largest consumers of cocoa and exporters of chocolate in the world. Because WBD has been responsible for drastic reductions in production in the countries where it occurs, the eventual introduction of the disease in Africa is a serious threat to the global cacao production and could lead to drastic economic losses in this industrial sector. The causal agent of WBD is the basidiomycete fungus Moniliophthora perniciosa. Genome and transcriptome studies on this fungus have provided a better understanding of the mechanisms pertaining to this peculiar plant-pathogen interaction. Although remarkable advances have been achieved, the development of effective strategies to control witches' broom disease is still required. The WBD transcriptome project, which was launched by Unicamp in collaboration with the High Throughput Sequencing Facility of UNC (University of North Carolina), aims to provide valuable information on the biology and pathogenicity mechanisms of M. perniciosa. In particular, the present work, which is part of the WBD transcriptome project, aims to unveil molecular mechanisms underpinning the M. perniciosa resistance to strobilurins, which are one of the most widely used classes of fungicides in the global agriculture. The potential results of this work might provide the basis for the development of new and effective strategies to control WBD. (AU)