De novo transcriptome sequencing of Nerium oleander L. for deciphering cardiac glycosides biosynthetic genes involved in the pathway

Nerium oleander L., under the family Apocynaceae, is a conventionally and therapeutically important plant, as many of its secondary metabolites and extracts have shown various pharmacological activities like cytotoxic, anti-proliferative, anti-viral, antimicrobial, etc. This plant is a rich source of diversified bioactive secondary metabolites, including alkaloids, flavonoids, tannins, phenolics, steroids, cardenolides, and cardiac glycosides etc. However, as the bioavailability of these compounds in wild plants is very less, their mass isolation may endanger this species in nature. Total chemical synthesis of these secondary metabolites is also very difficult due to their complex structure. The biosynthetic pathway for these pharmacologically important compounds from N. oleander has not been deciphered till date. Metabolomics and Transcriptomics resources can provide an important tool in elucidating a biosynthetic pathway for bioactive compounds in N. oleander. Discovery of genes and enzymes involved in bioactive compound metabolism will also play the foundation for a production platform for these important classes of pharmaceuticals and their development as a source of new drugs. Transcriptome sequencing of leaves of N. oleander was carried out for the mechanism of these secondary metabolites' biosynthesis.