Selection of Differentially Expressed Genes Using the Transcriptome Analysis of Ripening Grape Berries in Response to High Temperature

Purpose: The transcriptome of ‘Campbell Early’ grape berries exposed to high temperature was analyzed to select useful genes by evaluating their differential expression through sequencing short reads on Solexa platform. Research Method: We assembled 118 million high-quality trimmed reads using Velvet followed by Oases. Findings: Functional categorization of expressed transcripts revealed the conservation of genes involved in various biological processes like responses to chemical (12.7%), responses to abiotic stimulus (11.8%), biosynthesis processes (11.8%), and cellular metabolic processes (10.4%) in grape berries exposed to high temperature. The major up-regulated genes included isocitratelyase, cysteine proteinases superfamily protein, cupin family protein, and glycosyl hydrolase genes, and the major down-regulated genes included flavanone 3-hydroxylase, phenylalanine ammonia lyase, chlorophyll A-B binding family protein, and polygalacturonase inhibiting protein genes in grape berries exposed to high temperature. Among genes related to grape coloration, expressions of chalcone and stilbene synthase, flavanone 3-hydroxylase, leucoanthocyanidin dioxygenase, phenylalanine ammonia lyasegenes were more strongly inhibited in berries kept at 35°C than 25°C. Originality/Value: Transcript sets of grape berries generated in this study will provide a resource for gene discovery and development of functional molecular markers to be used in elucidating the mechanism of tolerance to high temperature