In our experiments, a representative number of 125 grape
samples have been collected. For the extraction and purification of
genomic DNA, a modified procedure for sample preparation (OIV,
2012) has been used together with the Nucleospin Food (MachereyeNagel,
Duren, Germany) DNA extraction kit. Grapes are a
complex food matrix including different substances such as colors,
tannins and polysaccharides that could inhibit subsequent enzymatic
reactions once present in the DNA extract and render fungal
DNA detection difficult. To surmount this obstacle, PVPP has been
used during the DNA extraction step. PVPP has been also used in
similar approximations for other fungal and bacterial DNA extractions
(Gil-Serna et al., 2009; OIV, 2012). The stabilizer PVPP is
frequently used for the selective adsorption of polyphenolic substances
and its monomeric pre components during the winemaking
process, without altering the desired sensory and quality
features of the products. The same procedure was followed in DNA
extraction for sterilized grape samples inoculated artificially with
different amounts of A. carbonarius conidia.