Elucidating biosynthetic pathway of piperine using comparative transcriptome analysis of leaves, root, and spike in Piper longum L.

Piper longum (Pipli; Piperaceae) is an important spice valued for its pungent alkaloids, especially piperine. Albeit, its importance, the mechanism of piperine biosynthesis is still poorly understood. The Next Generation Sequencing (NGS) for P. longum leaves, roots, and spikes were performed using Illumina platform, which generated 16901456, 54993496, and 22900035, respectively of high quality reads. In de novo assembly P. longum 173381 numbers of transcripts were analyzed. Analysis of transcriptome data from leaf, root, and spike showed gene families that were involved in the biosynthetic pathway of piperine and other secondary metabolites. To validate differential expression of the identified genes, 27 genes were randomly selected to confirm the expression level by quantitative real-time PCR (qRT-PCR) based on the up-regulation and down-regulation of differentially expressed genes obtained through comparative transcriptome analysis of leaves and spike of P. longum. With the help of UniProt database, the function of all characterized genes was generated.