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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research » Research » Research Project #433524

Research Project: Transferability of Natural Sulfite Production Among Commercial Wine Yeasts

Location: Horticultural Crops Research

Project Number: 2072-21220-003-17-G
Project Type: Grant

Start Date: Sep 1, 2017
End Date: Sep 30, 2018

Objective:
1. Sequence the genomes of a number of low sulfite-producing commercial wine yeast strains to determine the status of gene(s) relevant to sulfite production. 2. Introduce genes needed for the high sulfite production trait into the low sulfite producers to assess the feasibility of a potential breeding effort.

Approach:
Approximately 10 commercial wine yeast strains will be chosen for DNA sequencing. Strains will be selected on the basis of widespread use in the Oregon wine industry and the inability to produce high levels of sulfite during fermentation. Small lots of wine or model wine (<500 mL) will be made to assess sulfite production during fermentation. Sulfite will be determined enzymatically and by a high-throughput assay. Hydrogen sulfide (H2S) will be measured by standard methods. Student’s 2-tailed T test or the Wilcoxon–Mann-Whitney 2-tailed test will be used to assess the statistical significance of any differences observed in sulfite or hydrogen sulfide levels. Standard procedures will be used to isolate yeast genomic DNA which will be sequenced by Illumina high throughput sequencing. DNA will be prepared using Nextera XT kits and multiplexed for sequencing using MiSeq. Sequences will be mapped to the laboratory strain S288c genome to determine genetic variance of the chosen wine strains. “Read” data will be mapped to the reference genome using bowtie2 software which aligns the reads to the reference map. Sequence variants will be identified using SAMtools software which performs a quality control analysis of the individual sites, and bcftools software which confirms the sequence variants based on the SAMtools results.