Transcriptome analysis of Japanese wine grape 'Koshu'

'Koshu' is an important Japanese indigenous wine grape, but it possesses challenging traits for winemaking, including low sugar content and large berry size. This research performed transcriptome analysis (RNA sequencing) to investigate the molecular basis of these characteristics, using the international cultivar 'Chardonnay' as a reference. Total RNA was extracted from the berry flesh of Koshu and Chardonnay (three biological replicates for each) at 10 days after véraison using the RNeasy Plant Mini Kit (QIAGEN) with Fruit-mate for RNA Purification (Takara). Library preparation was performed using NEBNext Ultra RNA Library Prep Kit for Illumina (New England Biolabs). Sequencing was performed using an Illumina NovaSeq 6000 platform to comprehensively analyze differential gene expression in berry flesh between Koshu and Chardonnay. All samples showed more than 40 million read data. Thus, the sequence data can be used for RNA-seq analysis to identify key candidate genes for improving the 'Koshu' cultivar.