Response of the fungus Pseudocercospora griseola f. mesoamericana to Tricyclazole

ALEJANDRA BÁRCENA; GABRIELA PETROSELLI; SILVIA MELINA VELASQUEZ; JOSÉ M. ESTEVEZ; ROSA ERRA-BALSELLS; PEDRO BALATTI; MARIO SAPARRAT

MYCOLOGICAL PROGRESS

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2015

1617-416X

Pseudocercospora griseola, an anamorph of Mycosphaerella, causes Angular LeafSpot (ALS). The mycelia and conidia from P. griseola are coloured due to the synthesisof 1,8 dihydroxynaphthalene (DHN)- melanin. The aim of this work was to identify in P.griseola f. mesoamericana isolate T4, a highly pigmented fungus, intermediarycompounds as a result of the inhibition of melanin synthesis by tricyclazole and toanalyze at the structural level the localization of these dark pigments. The mainmetabolites were analyzed using ultraviolet matrix assisted laser desorption-ionizationmass spectrometry (UV-MALDI MS). Tricyclazole affected P. griseola f.mesoamericana in several different ways. The most evident effect was the reduction ofmelanin synthesis and therefore diffusible shunt products were found and identified.Flaviolin was the main intermediate metabolite found in cultures supplemented withtricyclazole. This inhibitor, which affected pigmentation and the cell wall structure ofmycelium, revealed macroscopically by the reduction in growth, decreased thestratification and deposition of melanin in the hyphal wall. These results suggest apossible role of tricyclazole to control ALS.