In a significant research outcome, Director Dr. Ajay Parida’s team at the Institute of Life Sciences, Bhubaneswar and Dr. M. Parani’s group at SRM Institute of Science and Technology, Tamil Nadu has sequenced the genome of one of the highly salt tolerant mangrove species Avicennia marina.

This is the first report of a reference grade genome assembly for any mangrove species reported so far.

Mangroves are a unique group of species found in marshy intertidal estuarine regions and survive a high degree of salinity through several adaptive mechanisms. They form a link between marine and terrestrial ecosystems, protect shorelines, and provide habitat for a diverse array of terrestrial organisms. Many marine fish species rely exclusively on mangroves as their breeding, spawning, and hatching grounds, noted the team members.

Avicennia marina (Gray mangrove) is one of the most prominent mangrove species found in all mangrove formations in India. It is a salt-secreting and extraordinarily salt-tolerant species that grows optimally in 75 percent seawater and tolerates >250% seawater, they said.

It is among the rare plant species, which can excrete 40 percent of the salt through the salt glands in the leaves, besides its extraordinary capacity to exclude salt entry to the roots.

Understanding the genetic basis of salt tolerance in this species therefore is significant for identification of salinity tolerant genes.

The research group have sequenced nearly 99 percent of the genome of the species and aligned them to 31chrmosomes of the species.

The study has been published in the recent issue of the Communications Biology (a nature group of journal).

The study employing the latest genome sequencing and assembling technologies have identified 31,477 protein-coding genes and a “salinome” consisting of 3246 salinity-responsive genes and homolog of 614 experimentally validated salinity tolerance genes.

Dr Parida said that “availability of the genome sequence of mangrove species will trigger a wide range of molecular studies not only in India but throughout the world”.

This study assumes significance as agriculture productivity globally is affected due to biotic stress factors such as limited water availability and salinization of soil and water. Availability of water is a significant challenge to crop production in dry land areas, accounting for ~40 percent of the world’s total land area.

“The genomic resources generated in the study will pave the way for researchers to study the potential of the identified genes for developing drought and salinity tolerant varieties of important crop species of the coastal region that is significant for India with 7,500km of coastline and two major island systems” said Dr. Parida.