De novo Transcriptome Assembly and Differential Expression Analysis of Catharanthus roseus in Response to Salicylic acid

Periwinkle (Catharanthus roseus) is the only source of the anti-cancer vinblastine and vincristine alkaloids. It has been documented that salicylic acid (SA) affects the accumulation of both alkaloids. However, the transcriptome data to unveil the induction effect(s) of SA appears limited so far. In this study, by using the RNA sequencing technique the de novo transcriptome assembly of C. roseus was performed. The result showed that the expression of all genes in the Terpenoid Indole Alkaloids (TIAs) pathway producing anti-cancer vinblastine and vincristine alkaloids was increased after SA treatment. These results were consistent with the measurements of vincristine alkaloid (the final product of the TIAs pathway) over time and showed that SA spray had a positive effect on both transcription and production of alkaloids. Also, bHLH, MYB and MYB-related, AP2 / ERF, WRKY, C2H2, C3H and bZIP transcription factor families were abundant, suggesting the role of diverse transcription families in response to SA stimulus. In microsatellite analyzes, out of the total 77192 SSRs were identified the di-nucleotides and tri-nucleotide SSRs were the most abundant SSR markers, accounting for 39% and 34% of the total SSR markers, respectively.