Inactivation of plant-pathogenic fungus Colletotrichum acutatum with natural plant-produced photosensitizers under solar radiation

Author(s)

Fracarolli, Leticia ; Rodrigues, Gabriela B. ; Pereira, Ana C. ; Massola Junior, Nelson S. ; Silva-Junior, Geraldo Jose ; Bachmann, Luciano ; Wainwright, Mark ; Bastos, Jairo Kenupp ; Braga, Gilberto U. L.

• Document type: Journal article
• Source: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY; v. 162, p. 402-411, SEP 2016.
• Web of Science Citations: 10

Abstract

The increasing tolerance to currently used fungicides and the need for environmentally friendly antimicrobial approaches have stimulated the development of novel strategies to control plant-pathogenic fungi such as antimicrobial phototreatment (APT). We investigated the in vitro APT of the plant-pathogenic fungus Colletotrichum acutatum with furocoumarins and coumarins and solar radiation. The compounds used were: furocoumarins 8-methoxypsoralen (8-MOP) and 5,8-dimethoxypsoralen (isopimpinellin), coumarins 2H-chromen-2-one (coumarin), 7-hydroxycoumarin, 5,7-dimethoxycoumarin (citropten) and a mixture (3:1) of 7-methoxycoumarin and 5,7-dimethoxycoumarin. APT of conidia with crude extracts from `Tahiti' acid lime, red and white grapefruit were also performed. Pure compounds were tested at 50 mu M concentration and mixtures and extracts at 12.5 mg L-1. The C. acutatum conidia suspension with or without the compounds was exposed to solar radiation for 1 h. In addition, the effects of APT on the leaves of the plant host Citrus sinensis were determined. APT with 8 MOP was the most effective treatment, killing 100% of the conidia followed by the mixture of two coumarins and isopimpinellin that killed 99% and 64% of the conidia, respectively. APT with the extracts killed from 20% to 70% of the conidia, and the extract from `Tahiti' lime was the most effective. No damage to sweet orange leaves was observed after APT with any of the compounds or extracts. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/15204-8 - Mechanistic study of the photodynamic inactivation of human and plant pathogenic fungi
• Grantee: Gilberto Úbida Leite Braga
• Support Opportunities: Regular Research Grants