CONICET | Buscador de Institutos y Recursos Humanos

The exudation of resins is considered as one of the most important defense mechanisms in conifers. The resins have the ability to protect against pathogenic agents, insects, and other types of damage. The resin composition of the Cupressaceae Austrocedrus chilensis (known as ?ciprés de la cordillera?) has been studied recently, but there is not information about the variability and properties of resins from different individuals, as well as in different functional conditions. This work considered the response of Austrocedrus chilensis against the pathogenic agent Phytophthora austrocedri, which is responsible for the devastating disease commonly named as ?mal del ciprés?. The study included the profiling of resin from healthy, naturally infected and artificially inoculated trees of A. chilensis and the possible detection of antifungal activity of the resin against P. austrocedri. Resin samples were collected in Los Alerces National Park, Argentina. The chemical analysis of the resins was carried out by GC-MS and 1H-NMR. To obtain semi-purified fractions of resin, preparative TLC of representative resin samples were performed. The antifungal activity assays were conducted in Petri dishes using tomato agar as culture medium amended with the different fractions of resin. The resin profiling showed differences between healthy and infected or artificially inoculated A. chilensis trees. Artificially inoculated and naturally infected trees showed the same profile. The preparative TLC gave nine fractions of semi-pure compounds. After a comparison by TLC, GC-MS and NMR analysis, five of the nine fractions were evaluated to analyze possible antifungal activity. Two fractions significantly inhibited the pathogen mycelial growth. The resin profile components, as well the description of composition of the fractions and their antifungal activity will be discussed.

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