RNA-Seq analysis and annotation of a draft blueberry genome assembly identifies candidate genes involved in fruit ripening, biosynthesis of bioactive compounds, and stage-specific alternative splicing.

TitleRNA-Seq analysis and annotation of a draft blueberry genome assembly identifies candidate genes involved in fruit ripening, biosynthesis of bioactive compounds, and stage-specific alternative splicing.
Publication TypeJournal Article
Year of Publication2015
AuthorsGupta V, Estrada AD, Blakley I, Reid R, Patel K, Meyer MD, Andersen SUggerhøj, Brown AF, Lila MAnn, Loraine AE
JournalGigascience
Volume4
Pagination5
Date Published2015
ISSN2047-217X
KeywordsAlternative Splicing, Anthocyanins, Base Sequence, Biosynthetic Pathways, Blueberry Plants, Databases, Genetic, Ethylenes, Fruit, Gene Expression Profiling, Gene Expression Regulation, Developmental, Gene Expression Regulation, Plant, Genome, Plant, Models, Genetic, Molecular Sequence Annotation, RNA, Plant, Sequence Alignment, Sequence Analysis, RNA
Abstract

<p><b>BACKGROUND: </b>Blueberries are a rich source of antioxidants and other beneficial compounds that can protect against disease. Identifying genes involved in synthesis of bioactive compounds could enable the breeding of berry varieties with enhanced health benefits.</p><p><b>RESULTS: </b>Toward this end, we annotated a previously sequenced draft blueberry genome assembly using RNA-Seq data from five stages of berry fruit development and ripening. Genome-guided assembly of RNA-Seq read alignments combined with output from ab initio gene finders produced around 60,000 gene models, of which more than half were similar to proteins from other species, typically the grape Vitis vinifera. Comparison of gene models to the PlantCyc database of metabolic pathway enzymes identified candidate genes involved in synthesis of bioactive compounds, including bixin, an apocarotenoid with potential disease-fighting properties, and defense-related cyanogenic glycosides, which are toxic. Cyanogenic glycoside (CG) biosynthetic enzymes were highly expressed in green fruit, and a candidate CG detoxification enzyme was up-regulated during fruit ripening. Candidate genes for ethylene, anthocyanin, and 400 other biosynthetic pathways were also identified. Homology-based annotation using Blast2GO and InterPro assigned Gene Ontology terms to around 15,000 genes. RNA-Seq expression profiling showed that blueberry growth, maturation, and ripening involve dynamic gene expression changes, including coordinated up- and down-regulation of metabolic pathway enzymes and transcriptional regulators. Analysis of RNA-seq alignments identified developmentally regulated alternative splicing, promoter use, and 3' end formation.</p><p><b>CONCLUSIONS: </b>We report genome sequence, gene models, functional annotations, and RNA-Seq expression data that provide an important new resource enabling high throughput studies in blueberry.</p>

DOI10.1186/s13742-015-0046-9
Alternate JournalGigascience
PubMed ID25830017
PubMed Central IDPMC4379747
Grant ListR01 GM103463 / GM / NIGMS NIH HHS / United States
R01 RR032048 / RR / NCRR NIH HHS / United States
1R01RR032048-01 / RR / NCRR NIH HHS / United States