Phenotypic and molecular genetics study of Geotrichum candidumLink (1809) and Geotrichum silvicola Pimenta (2005) cultivated on mitis salivarius agar.

BACKGROUND

Geotrichum is a genus of fungi found in different habitats throughout the world. Although Geotrichum and its related species have been extensively reclassified and taxonomically revised, it is still the target for many researches.

METHODS AND RESULTS

In this study, phenotypic and molecular genetics comparisons were performed between Geotrichum candidum and Geotrichum silvicola. Mitis Salivarius Agar was used as the growing medium for the phenotypic comparison study, which was carried out at two temperatures (20-25 and 37 °C). For genotypic comparison, we compared the 18 S, ITS, and 28 S sequences of universal DNA barcode regions of both species. Important findings on the new culture media for fungal isolation were revealed by the results. The phenotypic variation between the two species' colonies, including their shapes, sizes, textures and growth rates, were strikingly different. DNA sequences of both species showed that pairwise identities of the species were 99.9% for 18 S, 100% for ITS and 99.6% for 28 S regions.

CONCLUSIONS

Contrary to what is commonly seen, the results showed that 18 S, ITS and 28 S failed to discriminate the species. The first investigation into the performance of Mitis Salivarius Agar as a fungus culture medium is reported in this work, and proved its efficiency. Additionally, this is the first study to compare G. candidum with G. silvicola by means of both phenotypic and genotypic analysis.