De novo transcriptome of Taverniera cuneifolia (Roth) Ali.

Abstract

Taverniera cuneifolia has been described as a potent substitute of Licorice in India. It has been used as an expectorant, anti-inflammatory, anti-ulcer, wound healing, blood purifier etc. Glycyrrhizin is one of the most useful bioactive sesquiterpenoid present in this plant. The present study aim to carry out transcriptome analysis in root tissue of Taverniera cuneifolia to identify specific functional genes involved in the biosynthesis of secondary metabolites. The root transcriptome sequencing of Taverniera cuneifolia resulted in a total of ~7.29 Gb of raw data and generated 55,991,233 raw reads. The high quality reads were de novo assembled by Trinity assembler followed through CD-HIT resulted into 35,590 "Unigene" transcripts with an average size of 419 bp. The unigenes were analyzed using BLAST2GO resulted in 27,884 (78.35%) transcript with blast hits, 22,510 (63.25%) transcript with mapping and 21,066 (59.19%) transcript with annotation. Functional annotation was carried out using NCBIs non-redundant and Uniprot databases resulted in the identification of 21,066 (59.19%) annotated transcripts and GO assigned to 24751 (69.54%) transcripts. The gene ontology result shows maximum sequences match with Biological Processes (48%), Molecular Function (27%) and Cellular components (23%). A total of 289 metabolic enriched pathways were identified, which included pathways like Sesquiterpenoid and triterpenoid pathway which were involved in synthesis of secondary metabolite Glycyrrhizin biosynthesis. The enzymes, squalene monooxygenase, farnesyl-diphosphate farnesyltransferase, beta amyrin synthase, beta-amyrin 24-hydroxylase, were identified by functional annotation of transcriptome data. There were several other pathways like terpenoid backbone biosynthesis, steroid biosynthesis, Carotenoid biosynthesis, Flavonoids biosynthesis etc. which have been reported first time from this plant. Transcription factors were predicted by comparison with Plant Transcription Factor Database, and 1557 trancripts belonging to 85 trancription factor families were identified. This transcriptome analysis provided an important resource for future genomic studies in Taverniera cuneifolia, therefore representing basis in further investigation of the plant. SignificanceLicorice (Glycyrrhiza glabra roots) is used as traditional Chinese herbal medicines in majority of formulations. Licorice is also used in Industries like food, herbal and cosmetics etc. due to its high demand in the market it is imported from foreign countries and is not available locally of superior quality (Liu et al., 2015). In India, Taverniera cuneifolia has been described as a potent substitute of Licorice, it has been quoted in ancient books like Charak Samhita during the Nigandu period (Kamboj, 2000) and Barda dungar ni Vanaspati ane upyog (Thaker 1910). It has been used as an expectorant, anti-inflammatory, anti-ulcer, wound healing, blood purifier etc. Transcriptomic studies will assist in understanding the basic molecular structure, function and organization of information within the genome of Taverniera cuniefolia. This study will help us to identify the key metabolites their expressions and genes responsible for their production.