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

Aims: 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 community profiles from grapes, in order to monitor fungi potentially involved in wine defects. Methods and Results: A fragment of the beta-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 beta-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. Conclusion: 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. Significance and Impact of the Study: A better knowledge of the fungal diversity on grapes, particularly species responsible for wine defect, is necessary to develop accurate molecular detection tools.