Stemphylium lycopersici isolates virulence depends on the synthesis of phytotoxic metabolites, which is modified by the environment

MEDINA, ROCIO; FRANCO, ERNESTO; LUCENTINI, CÉSAR GUSTAVO; SILVINA YAMILA LOPEZ; MARIO CARLOS NAZARENO SAPARRAT; BALATTI, PEDRO A.; ROSSO, JANINA

Boston

Congreso; International Congress of Plant Pathology (ICPP) 2018: Plant health in a global economy; 2018

APS

The etiological agents of tomato gray leaf spot are three necrotrophic species of the genus Stemphylium. Secondary metabolites (SMs) are a highly diverse set of low molecular weight bioactive compounds that play different biological roles. We hypothesized that S. lycopersici isolates that differ on disease severity and sporulation capacity produces differential soluble SMs. Cultures of S. lycopersici were grown on V8 and PDA plates at 25°C for 14 days and then were dried and aqueous soluble metabolites were extracted by sonication and filtration through a 0.22 μm pore-size membrane. Spectroscopic analysis were performed (UV?Vis absorption spectra and fluorescence?excitation-emission matrices). Toxicity of extracts was evaluated in vitro by means of a detached leaflet assay. PDA and V8 media extracts showed a maximum of absorbance at 450 nm. No maximum of absorbance was detected in the culture extract of CIDEFI-213 isolate grown on V8 medium. Differences of fluorescence intensity and emission region were observed between the extracts. The culture extract of CIDEFI-216 were toxic on tomato leaflets (p