Photodynamic inactivation of conidia of the fungus Colletotrichum abscissum on Citrus sinensis plants with methylene blue under solar radiation

Autor(es)

Gonzales, Julia C. ^[1] ; Brancini, Guilherme T. P. ^[1] ; Rodrigues, Gabriela B. ^[1] ; Silva-Junior, Geraldo Jose ^[2] ; Bachmann, Luciano ^[3] ; Wainwright, Mark ^[4] ; Braga, Gilberto U. L. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Anal Clin Toxicol & Bromatol, Ribeirao Preto - Brazil

^[2] Fundecitrus, Fundo Def Citricultura, Araraquara - Brazil

^[3] Univ Sao Paulo, Dept Fis, Fac Filosofia Ciencias & Letras Ribeirao Preto, Ribeirao Preto - Brazil

^[4] Liverpool John Moores Univ, Sch Pharm & Biomol Sci, Liverpool L3 3AF, Merseyside - England

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY; v. 176, p. 54-61, NOV 2017.
• Citações Web of Science: 6

Resumo

Antimicrobial photodynamic treatment (APDT) is a promising light based approach to control diseases caused by plant-pathogenic fungi. In the present study, we evaluated the effects of APDT with the phenothiazinium photosensitizer methylene blue (MB) under solar radiation on the germination and viability of conidia of the pathogenic fungus Colletotricum abscissum (former Colletotrichum acutatum sensu lato). Experiments were performed both on petals and leaves of sweet orange (Citrus sinensis) in different seasons and weather conditions. Conidial suspensions were deposited on the leaves and petals surface, treated with the PS (25 or 50 mu M) and exposed to solar radiation for only 30 min. The effects of APDT on conidia were evaluated by counting the colony forming units recovered from leaves and petals and by direct evaluating conidial germination on the surface of these plant organs after the treatment. To better understand the mechanistic of conidial photodynamic inactivation, the effect of APDT on the permeability of the conidial plasma membrane was assessed using the fluorescent probe propidium iodide (PI) together with flow cytometry and fluorescence microscopy. APDT with MB and solar exposure killed C. abscissum conidia and prevented their germination on both leaves and petals of citrus. Reduction of conidial viability was up to three orders of magnitude and a complete photodynamic inactivation was achieved in some of the treatments. APDT damaged the conidial plasma membrane and increased its permeability to PI. No damage to sweet orange flowers or leaves was observed after APDT. The demonstration of the efficacy of APDT on the plant host represents a further step towards the use of the method for control phytopathogens in the field. (AU)

• Processo FAPESP: 14/04162-8 - Estudo mecanístico da inativação fotodinâmica de fungos patogênicos com novos fotossensibilizadores
• Beneficiário: Júlia Cunha Gonzales
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 12/15204-8 - Estudo mecanístico da inativação fotodinâmica de fungos patógenos de humanos e de fungos fitopatógenos
• Beneficiário: Gilberto Úbida Leite Braga
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/11386-5 - Estudo mecanístico da percepção e da resposta a luz visível no fungo entomopatogênico Metarhizium acridum
• Beneficiário: Gilberto Úbida Leite Braga
• Modalidade de apoio: Auxílio à Pesquisa - Regular