Chemical and biological investigation of metabolites produced by Aspergillus unguis (CBMAI 2140) to combat citrus canker

Abstract

Citrus canker is a disease caused by the bacterium Xanthomonas citri subsp. citri (X. citri), which attacks all citrus species and varieties of commercial importance. Brazil annually faces significant economic losses in orchards due to citrus canker. Some current ways of controlling the disease involve: planting cultivars less susceptible to canker, installing windbreaks in orchards and using regular sprays of copper-based formulations. Such measures, although effective, are palliative, since the resistance to copper in X. citri has already been documented, in addition to the fact that this is a bio-accumulative and toxic metal. Thus, the search for sustainable ways to combat citrus canker becomes necessary. An alternative to synthetic chemicals is the application of natural pesticides, which are products originating from plants and microorganisms that act in the control of pests and diseases. Our research group has been dedicated to searching for natural products produced by microorganisms with potential action against X. citri. In previous works, we found fungi producing extracts with antibacterial activity against X. citri. We have recently been able to isolate and identify some bioactive substances present in these extracts. This project intends to continue the production, bioguided isolation and identification of bioactive natural products against X. citri present in the bioactive extract produced by Aspergillus unguis (CBMAI 2140), an endophytic fungus isolated from leaves of Passiflora incarnata Linnaeus. It is also intended to investigate the mechanism of action of these compounds in X. citri and the potential action of these compounds in the control of citrus canker in planta.