Researchers at the Indian Institute of Science Education and Research, Bhopal (IISER Bhopal), have completed the first-ever genome sequencing of the jamun tree (Syzygium cumini), an evergreen popular in India for its medicinal properties, fruits, and ornamental value. 

To understand the genomic and evolutionary basis of the tree’s medicinal value, the research team sequenced the genome using Oxford Nanopore and 10x Genomics sequencing technologies. Jamun is the largest genome sequenced from the world’s largest tree genus, Syzygium. 

The team, led by Dr Vineet K Sharma, Professor, Department of Biological Sciences, includes Abhisek Chakraborty, Shruti Mahajan, and Manohar Singh Bisht.   

The aim of this research was to gain new functional and evolutionary insights from the jamun genome, which could be responsible for the wide range of pharmacological properties of this species conferred by the bioactive compounds that act as nutraceutical agents in modern medicine,” says Sharma.

On the insights gained, Sharma said, “Taken together, it is tempting to speculate that the adaptive evolution of major plant secondary metabolism pathways in S cumini species confers unprecedented antidiabetic, antioxidant, anti-inflammatory, and other pharmacological properties of this tree. Further, the whole genome sequence of S cumini will facilitate future genomic, evolutionary, and ecological studies on the world’s largest tree genus.” 

Jamun, jambolan, or black plum is a Myrtaceae plant family tropical tree. Its natural range includes the Indian sub-continent and South-East Asia. The genus Syzygium contains 1,193 recognised species, including jamun.  

JIn Ayurveda the black plum is used to treat ailments such as stomach discomfort, arthritis, cardiac problems, flatulence, asthma, diarrhoea, and stomach spasms.

Clinical studies have also shown it to contain bioactive components such as flavonoids, polyphenols, antioxidants, iron, and vitamin C. “This attempt by IISER-Bhopal is the first time that the plant has been examined and decoded so closely,” according to a press release from the institute. 

The jamun genome has a higher number of coding genes resulting from gene duplication or neopolyploidy events, compared to the other two sequenced species from this genus. This duplication of genes can allow jamun to acquire novel functions. 

The analyses revealed the key genes involved in facilitating the adaptive evolution of Jamun. Among these, 14 genes allow for the biosynthesis of terpenoids, which are a diverse class of metabolites responsible for plant defence responses. They also contribute significantly to antioxidant and anti-inflammatory properties.  

Moreover, alkaloids, another type of metabolite, are also found abundantly in different plant parts and offer curative properties against many diseases. This combination of alkaloids and flavonoids gives the plant its anti-arthritic properties, the researchers suggest.

To explain the anti-diabetic properties of this plant, the researchers discovered the presence of glucosides, another class of metabolites that prevent the conversion of starch into sugar. Previous clinical assessments have shown that jamun has a low glycaemic index and alleviates diabetic symptoms such as excessive urination.  

Jamun also has genes that make the plant rugged and improve its stress tolerance to factors like weeds, insects, salinity, and drought. This points to remarkable adaptive evolution in jamun, the research team says.