Diagnosi molecolare e associazione di funghi di azzurramento del legno a insetti vettori in pinete alpine.

This work, done in the laboratories of the Department of Environmental Agronomy and Crop Science, located on the campus of Agripolis, aims at studying, using molecular techniques, the composition of fungi associated to Ips acuminatus in in several sites of the Alps. According to literature, this bark beetle is typically associated with three fungal species: Ophiostoma brunneo-ciliatum, O. ips and Ambrosiella macrospora. In particular, this work uses a Nested PCR technique to characterize the frequency of associated species on the insect, only amplifying the species of interest. Samples were collected from two plants in six different locations, the fungal DNA was extracted using a salting out protocol for the museum samples and then amplified using specific primers. The results were visualized with electrophoresis and then analyzed using a generalized linear mixed model. The analysis has concerned only one of the two species of Ophiostoma because the primers designed for O. brunneo-ciliatum turned out to be unspecific in the Nested PCR reaction. The statistical analysis showed that A. macrospora is significantly more associated to Ips acuminatus than O. ips. The results were also analyzed taking into account the sex of the insect and the site from which the samples but no significant differences were found. This can be explained as a greater need by the beetle to have a trophic symbiosis, rather than a symbiosis with a blue stain fungus, as Ambrosiella provides food for the larvae while Ophiostoma may reduce the tree defenses and facilitate the colonization of the bark by the beetle. The trophic symbiosis is indeed very important for the development of the larvae.