Transcriptome analyses of a Chinese hazelnut species Corylus mandshurica

BACKGROUND: Corylus was renowned for its production of hazelnut and taxol. To understand the local adaptation of Chinese species and speed up breeding efforts in China, we analyzed the leaf transcriptome of Corylus mandshurica, which had a high tolerance to fungal infections and cold. RESULTS: A total of 12,255,030 clean pair-end reads were generated and then assembled into 37,846 Expressed Sequence Tag (EST) sequences. During functional annotation, 26,565 ESTs were annotated with Gene Ontology (GO) terms using Blast2go and 11,056 ESTs were grouped into the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using KEGG Automatic Annotation Server (KAAS). We identified 45 ESTs that were homologous to enzymes and transcription factors responsible for taxol synthesis. The most differentiated orthologs between C. mandshurica and a European congener, C. avellana, were enriched in stress tolerance to fungal resistance and cold. CONCLUSIONS: In this study, we detected a set of genes related to taxol synthesis in a taxol-producing angiosperm species for the first time and found a close relationship between most differentiated genes and different adaptations to fungal infection and cold in C. mandshurica and C. avellana. These findings provided tools to improve our understanding of local adaptation, genetic breeding and taxol production in hazelnut.