DE NOVO TRANSCRIPTOME SEQUENCEING AND COMPARATIVE ANALYSIS OF DIFFERENTIALLY EXPRESSED GENES IN DRYOPERIS FRAGRANS UNDER TEMPERATURE STRESS

Dryopteris fragrans is a species of fern and contains flavonoids compounds with medicinal value. This study explain the temperature stress impact flavonoids synthesis in D. fragrans tissue culture seedlings under the low temperature at 4 degrees C, high temperature at 35 degrees C and moderate temperature at 25 degrees C. By using Illumina HiSeq 2000 sequencing, 80.9 million raw sequence reads were de novo assembled into 66,716 non-redundant unigenes. 38,486 unigenes (57.7%) were annotated for their function. 13,973 unigenes and 29,598 unigenes were allocated to gene ontology (GO) and clusters of orthologous group (COG), respectively. 18,989 sequences mapped to 118 Kyoto Encyclopedia of Genes and Genomes Pathway database (KEGG), 204 genes were involved in flavonoid biosynthesis, regulation and transport. 25,292 and 16,817 unigenes exhibited marked differential expression in response to temperature shifts of 25 degrees C to 4 degrees C and 25 degrees C to 35 degrees C, respectively. 4CL and CHS genes involved in flavonoid biosynthesis were tested and suggested that they were responsible for biosynthesis of flavonoids. This study provides the first published data to describe the D. fragrans transcriptome and should accelerate understanding of flavonoids biosynthesis, regulation and transport mechanisms. Since most unigenes described here were successfully annotated, these results should facilitate future functional genomic understanding and research of D. fragrans.