New environmental-friendly compounds to combat citrus canker

Abstract

The culture of citrus fruits is one of the most important agricultural economic activities in Brazil, notably in the state of São Paulo. Citrus culture is constantly under threat of plant diseases. A major disease is citrus canker that is caused by the bacterial plant pathogen Xanthomonas citri subsp. citri (Xac). Current modes of prevention of plant infection by Xac or the spreading of infection to new areas include spraying trees with copper containing bactericides and eradication of trees. Despite all the efforts made to control citrus diseases, last decade registered the loss of an enormous amount of trees (corresponding to around 300 Million tons of fruit/year) and a negative impact on soil quality is expected since copper accumulates in the environment. Therefore, more sustainable ways to combat citrus canker are urgently needed. The Brazilian partner in this proposal has recently identified and characterized a class of plant-derived semi-synthetic compounds, the alkyl gallates, with promising activity against Xac. The Dutch partner in this proposal is currently involved in the identification of the bacterial target of the alkyl gallates and initial results strongly suggest that the target of the compounds is the essential bacterial cell division protein FtsZ. Our very promising initial results form the basis of this proposal, that aims to improve the sustainability of citriculture by developing novel, environmental-friendly, antibacterials to combat Xac. We will use existing and novel lead compounds with activity against Xac as a platform for chemical synthesis to enhance the antibacterial activity. The bacterial targets of the compounds and their modes of action will be characterized in detail. Finally, experiments to evaluate the efficacy of these compounds in the field and their toxicity to plants and animals will be determined. Combined, we expect to develop compounds that can be used as a sustainable method to combat citrus canker and contribute with new alternatives to control the spread of Xac in citrus orchards.