Transcriptome analysis of Ajowan (Trachyspermum ammi L.) inflorescence

Trachyspermum ammi (L.) Sprague, commonly known as ‘Ajowan’, belongs to the family ‘Apiaceae’. Ajowan fruits yield 2–6% essential oil, and thymol is the major constituent of the oil (35–60%). T. ammi is of high medicinal value; however, the genomic resources for this medicinal plant are rare. To obtain transcript sequences of ajowan inflorescence, RNA-Seq was applied using Illumina HiSeq 2000 platform. Following de novo assembly, 68051 unigenes were produced, among which 43156 unigenes were annotated against different sequence databases. Blastx results of ajowan unigenes showed that 41950 and 29273 unigenes were hit in the NCBI non-redundant (Nr) protein and UniProt databases, respectively. Gene Ontology (GO) classification showed that 29258 unigenes were categorized into 55 GO terms, and 26002 unigenes were clustered in the Orthologous Group categories. Blastx results against the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database indicated that 14986 unigenes were represented in 127 pathways. In addition, 8751 sequences containing simple sequence repeats (SSRs) and 1180 putative transcription factor genes were also identified. As far as we know, this repository of genomic information is the first resource currently available for transcriptome characterization, gene discovery, developing SSR molecular markers and future genomic research on ajowan.