Aim: Grapes are submitted to several fungal attacks, which can impair quantity and quality of the resulting wine. The aim of this paper is to describe sets of primers that are able to easily characterise the strains isolated on the grapes by DNA sequencing.
Methods and results: Four sets of primers targeting the beta-tubulin and Internal Transcribed Spacer (ITS) regions were used. Samples were isolated from grey or green moulds on mature berries during 5 years in vineyards located in the Moselle Valley of Luxembourg. Identifications were performed by comparing the obtained sequences with referenced sequences using several databases. The isolates obtained from the grey mould were identified as Botrytis cinerea, Mucor fragilis and Chaetomium globosum, whereas on green mould, Penicillium expansum, Penicillium minioluteum, Davidiella tassiana and Cladosporium cladosporioides were recovered. Identification may be impossible for two reasons : samples may not display a sequence of sufficient quality, which can tentatively be solved by cloning the PCR amplicon, or databases may not be exhaustive enough to unambiguously determine the species. We therefore suggest primer sets for each species according to these limiting factors.
Conclusion: The performances of the primers were species-dependent. Even though the ITS region is more highly represented in the databases than the beta-tubulin region, technical results were better for beta-tubulin sequences.
Significance and impact of the study: This work provides a basic methodology for the molecular characterisation of the fungal flora encountered on grapes.
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