Evaluation of PCR-DGGE methodology to monitor fungal communities on grapes

Some fungi present on the surface of grapes may have a negative effect on the quality of wine. The aim of this study was to evaluate PCR-denaturing gradient gel electrophoresis (PCR-DGGE), for the establishment of fungal com- munity profiles from grapes, in order to monitor fungi potentially involved in wine defects. A fragment of the b-tubulin gene was amplified from filamentous fungi and yeasts described from grapes and analysed using two different denaturing gradient gels to constitute a reference database. The use of b-tubulin sequences instead of ITS rDNA in PCR-DGGE showed a progress in the discrimination of these fungal species but comigration problems were still observed. The technique was then applied on grape samples. The profiles counted up to 10 bands of which half corresponded to species which were not recorded in the reference database. PCR-DGGE represents a useful tool to compare environmental samples for the study of the dynamics of fungal communities, but comigrations represent a limit in its use to describe the species present. A better knowledge of the fungal diver- sity on grapes, particularly species responsible for wine defect, is necessary to develop accurate molecular detection tools.