Proteomic response of the phytopathogen Phyllosticta citricarpa to antimicrobial volatile organic compounds from Saccharomyces cerevisiae
Mauricio Batista Fialho, Alexander de Andrade, JosÚ Matheus Camargo Bonatto, Fernanda Salvato, Carlos Alberto Labate, SÚrgio Florentino Pascholati
Departamento de Fitopatologia e Nematologia, Escola Superior de Agricultura “Luiz de Queiroz” (ESALQ), Universidade de São Paulo (USP), Avenida Pádua Dias, 11, CP 09, CEP 13418-900 Piracicaba, SP, Brazil.
Volatile organic compounds (VOCs) released by Saccharomyces cerevisiae inhibit plant pathogens, including the filamentous fungus Phyllosticta citricarpa, causal agent of citrus black spot. VOCs mediate relevant interactions between organisms in nature, and antimicrobial VOCs are promising, environmentally safer fumigants to control phytopathogens. As the mechanisms by which VOCs inhibit microorganisms are not well characterized, we evaluated the proteomic response in P. citricarpa after exposure for 12 h to a reconstituted mixture of VOCs (alcohols and esters) originally identified in S. cerevisiae. Total protein was extracted and separated by 2D-PAGE, and differentially expressed proteins were identified by LC–MS/MS. About 600 proteins were detected, of which 29 were downregulated and 11 were upregulated. These proteins are involved in metabolism, genetic information processing, cellular processes, and transport. Enzymes related to energy-generating pathways, particularly glycolysis and the tricarboxylic acid cycle, were the most strongly affected. Thus, the data indicate that antimicrobial VOCs interfere with essential metabolic pathways in P. citricarpa to prevent fungal growth.
Keywords: Antifungal; Citrus; Guignardia; Mechanism of action; Postharvest; Volatiles.