Cellular damage induced by harmol on Penicillium digitatum and Botrytis cinerea

G. M. OLMEDO; L. CERIONI; M. M. GONZALEZ; F. M. CABRERIZO; V. A. RAPISARDA; S. I. VOLENTINI

Simposio; SAIB, 51 Annual Meeting Argentine Society for Biochemistry and Molecular Biology. LI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

P. digitatum and B. cinerea are postharvest fungal phytopathogens, causal agents of green and grey molds, respectively. To control them, treatments with fungicides are used. Due to resistant strains proliferation, development of alternatives for decay control becomes important. β-Carboline (βC) are plant alkaloids with a wide spectrum of antimicrobial properties. Here, inhibitory action of the βC harmol (Hol) at different concentrations in 24h-incubations was tested against both phytopathogens. After incubation with 1 mM Hol at pH 5, UFC/ml decreased from 10 for P. digitatum, while no viable conidia were observed for B. cinerea. In contrast, CFU/ml remained unmodified at pH 9 for both fungi. To analyze membrane integrity, conidia exposed to Hol were incubated with Sytox Green, and broad dye incorporation was observed for both pathogens. The intracellular ROS production was determined using the H DCFDA probe. For B. cinerea treated with Hol, a ROS increment detected, while they were not generated in P. digitatum. In addition, ultrastructural changes in conidia were analyzed by TEM, revealing severe cellular damage.Our data show that Hol at pH 5 alters conidia ultrastructure and membrane integrity of both fungi, while increased ROS production was only observed in B. cinerea. These findings represent the first insights to elucidate Hol mode of action against phytopathogen fungi. 26 to 104