Isolation and anti-Xanthomonas citri activity of unguinol produced by Aspergillus unguis CBMAI 2140

Author(s)

dos Santos, Eduarda Araujo ; Marin, Vitor Rodrigues ; de Angelis, Derlene Atilli ; Ferreira, Henrique ; Sass, Daiane Cristina

• Document type: Journal article
• Source: Letters in Applied Microbiology; v. 78, n. 2, p. 8-pg., 2025-02-25.

Abstract

This research investigated active biomolecules from the endophytic fungus Aspergillus unguis (CBMAI 2140), isolated from Passiflora incarnata leaves, as potential antibacterial agents against Xanthomonas citri subsp. citri, the causative agent of citrus canker. The fungal extract was obtained via liquid-liquid extraction with ethyl acetate. Antibacterial activity was assessed using the Resazurin Microtiter Assay Plate, determining inhibitory concentrations (IC90) and the minimum bactericidal concentration (MBC). The extract displayed microbicidal activity at 1050 mu g ml-(1) and inhibited bacterial growth at 350 mu g ml-(1). Fractionation of the extract via normal-phase column chromatography yielded six fractions, with fraction F11 showing the highest antibacterial potential (MBC: 200 mu g ml-(1)). Nuclear magnetic resonance analysis identified Unguinol as the main compound in F11. Fluorescence microscopy demonstrated rapid permeabilization of the X. citri cell membrane upon exposure to the compound, with significant effects observed after 15-30 min. Although no notable anti-biofilm activity was detected, this study represents the first report of Unguinol's antibacterial activity against Xanthomonas species. These findings highlight its potential for agricultural applications, contributing to sustainable development goal 2. (AU)

• FAPESP's process: 22/10238-3 - Chemical and biological investigation of metabolites produced by Aspergillus unguis (CBMAI 2140) to combat citrus canker
• Grantee: Eduarda Araujo dos Santos
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 24/11225-8 - Assessment of biopesticides presence, retention and biodegradation residues in citrus leaves, fruit and soil.
• Grantee: Vítor Rodrigues Marin
• Support Opportunities: Scholarships in Brazil - Support Program for Fixating Young Doctors
• FAPESP's process: 18/11747-3 - Evaluation of the biotechnological potential of microorganisms in the production of antibacterial substances for use in agriculture.
• Grantee: Daiane Cristina Sass
• Support Opportunities: Regular Research Grants