Pseudomonas fluorescens showing antifungal activity against macrophomina phaseolina, a severe pathogenic fungus of soybean, produces phenazine as the main active metabolite

• Autores: Castaldi, Stefany; Masi, Marco; Sautua, Francisco José; Cimmino, Alessio; Isticato, Rachele; Carmona, Marcelo Aníbal; Tuzi, Angela; Evidente, Antonio
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Biomolecules; Vol.11, no.11; art.1728; https://www.mdpi.com/
• Materia: PSEUDOMONAS FLUORESCENS; MACROPHOMINA PHASEOLINA; PHENAZINE; PHENAZINE ANALOGS AND DERIVATIVES; SOYBEAN PATHOGENS; ANTIFUNGAL ACTIVITY; SAR
• Institución: Universidad de Buenos Aires. Facultad de Agronomía

Fil: Castaldi, Stefany. Università di Napoli Federico II. Dipartimento di Biologia. Complesso Universitario Monte S. Angelo. Via Cintia, Napoli, Italy.
Fil: Masi, Marco. Università di Napoli Federico II. Dipartimento di Scienze Chimiche. Complesso Universitario Monte S. Angelo. Via Cintia, Napoli, Italy.
Fil: Sautua, Francisco José. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología. Buenos Aires, Argentina.
Fil: Cimmino, Alessio. Università di Napoli Federico II. Dipartimento di Scienze Chimiche. Complesso Universitario Monte S. Angelo. Via Cintia, Napoli, Italy.
Fil: Isticato, Rachele. Università di Napoli Federico II. Dipartimento di Biologia. Complesso Universitario Monte S. Angelo. Via Cintia, Napoli, Italy.
Fil: Carmona, Marcelo Aníbal. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Fitopatología. Buenos Aires, Argentina.
Fil: Tuzi, Angela. Università di Napoli Federico II. Dipartimento di Scienze Chimiche. Complesso Universitario Monte S. Angelo. Via Cintia, Napoli, Italy.
Fil: Evidente, Antonio. Università di Napoli Federico II. Dipartimento di Scienze Chimiche. Complesso Universitario Monte S. Angelo. Via Cintia, Napoli, Italy.
Pseudomonas fluorescens 9 and Bacillus subtilis 54, proposed as biofungicides to control Macrophomina phaseolina, a dangerous pathogen of soybean and other crops, were grown in vitro to evaluate their ability to produce metabolites with antifungal activity. The aim of the manuscript was to identify the natural compounds responsible for their antifungal activity. Only the culture filtrates of P. fluorescens 9 showed strong antifungal activity against M. phaseolina. Its organic extract contained phenazine and mesaconic acid (1 and 2), whose antifungal activity was tested against M. phaseolina, as well as Cercospora nicotianae and Colletotrichum truncatum, other pathogens of soybean; however, only compound 1 exhibited activity. The antifungal activity of compound 1 was compared to phenazine-1-carboxylic acid (PCA, 3), 2-hydroxyphenazine (2-OH P, 4), and various semisynthetic phenazine nitro derivatives in order to perform a structure–activity relationship (SAR) study. PCA and phenazine exhibited the same percentage of growth inhibition in M. phaseolina and C. truncatum, whereas PCA (3) showed lower activity against C. nicotianae than phenazine. 2 Hydroxyphenazine (4) showed no antifungal activity against M. phaseolina. The results of the SAR study showed that electron attractor (COOH and NO2) or repulsor (OH) groups significantly affect the antifungal growth, as well as their α- or B - location on the phenazine ring. Both PCA and phenazine could be proposed as biopesticides to control the soybean pathogens M. phaseolina, C. nicotianae, and C. truncatum, and these results should prompt an investigation of their large-scale production and their suitable formulation for greenhouse and field applications.
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