CSIR lab completes genome sequencing of tulsi plant

The Council of Scientific and Industrial Research (CSIR) has succeeded in whole genome sequencing of medicinal plant `Holy basil' (tulsi), marking the first step towards unravelling the secrets of its therapeutic potential.

CSIR-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow has published whole genome sequence of `Ocimum Sanctum', the wonder plant , which is both used as an essential medicinal plant and revered as 'Vishnupriya' and worshipped for over 3.000 years in India.

This is the first report of complete genome sequence of a traditional and most revered medicinal plant in India, using a composite next generation sequencing technologies, a CSIR release stated.

Considering the metabolic and therapeutic potential of this plant, the availability of whole genome sequence is the first step to understanding and unravelling the secrets of this 'mother of all herbs' and to provide scientific validity to the traditional claims of its utility in diverse medicinal usage, the release noted

Being a popular household plant in India, tulsi is traditionally used for the cure of several ailments. This herb is described as `The Queen of Herbs,' `The Incomparable One' and `The Mother Medicine of Nature' in the Ayurvedic text Charaka Samhita.

All parts of this herb (dried leaf, dried seed, and dried whole plant) are used in several systems of traditional medicine, including Ayurveda, Greek, Roman, Siddha, and Unani.

It is used in the preparations to cure various diseases like bronchitis, bronchial asthma, malaria, diarrhoea, dysentery, skin diseases, arthritis, painful eye diseases, chronic fever, insect bite etc.

It has also been described to possess anti-fertility, anti-cancer, anti-diabetic, anti-fungal, anti-microbial, hepatoprotective, cardioprotective, anti-emetic, anti-spasmodic, analgesic, adaptogenic and diaphoretic actions.

Many of the basil oil constituents have found applications as medicinal ingredients, flavors, fragrance, etc.

Tulsi is rich in phenylpropanoids, terpenoids and their derivatives, and many of these are implicated for different therapeutic activities.

The availability of the genome sequence now opens the possibility to identify genes involved in producing therapeutic molecules and to produce them in vitro.

This will also facilitate identification of not yet identified genes involved in the synthesis of important secondary metabolites in this plant.

Specific pathway related genes identified or mined in this genome could be used for the production of secondary metabolites following synthetic biology approaches.

The development of molecular tools and genomic resources will accelerate molecular breeding and ultimately the utility of Tulsi in medical community.

The nuclear genome of Tulsi is the smallest (386 Mb) in the family Lamiaceae family of plants while the chloroplast genome (142,245 bp) is the smallest in the order Lamiale plantss. According to the chloroplast genome similarity, O. sanctum shows maximum evolutionary closeness to Salvia miltiorrhiza, a plant of the Chinese system of traditional medicine.

Although, both these plants predominantly produce phenylpropanoids, and both have the identical diploid number of chromosomes (2n = 16), the genome size of O. sanctum (386 Mb) is a little more than half of the genome size of S.miltiorrhiza indicating that O. sanctum genome is more compact than that of S. miltiorrhiza.