De novo transcriptome sequencing in Monsonia burkeana revealed putative genes for key metabolic pathways involved in tea quality and medicinal value

Monsonia (Monsonia burkeana Planch. ex Harv) is one of the most valuable tea and traditional medicinal plants used in Southern Africa. In spite of this, there is no sequence information regarding this plant in literature. To provide understanding of the naturally occurring tea and drug-specific products and the key pathways for the biosynthesis of these molecules, we sequenced the leaf transcriptome using Illumina MiSeq platform and generated 2,590,652 paired-end reads that were assembled de novo into 45,450 high-quality transcripts. Annotation of these transcripts revealed best hits for homology to discover more than 17,800 functional genes and conserved domains. A total of 93 KEGG pathways and associated genes encoded by more than 90% of the coding transcripts are responsible for the biosynthesis of these life-saving metabolites. We validated and enriched the genes by GO annotation and linked this to enzyme-powered pathways through interactive network map. Caffeine metabolism, flavonoid, phenylpropanoid and terpenoids biosynthesis and xenobiotics degradation were typical in tea quality and drug therapy. The relatedness of more than 80 gene families encoding key enzymes was shown using unrooted phylogenetic tree. In conclusion, the M. burkeana leaf transcriptome gives insight into tea and drug-specific products, therefore representing basis in further investigation of the plant.