Context: Recently, the scientists at the DBT-Institute of Life Sciences and SRM-DBT Partnership Platform for Advanced Life Sciences Technologies have decoded the genome of a Salt-secreting Mangrove Species ‘Avicennia marina’.
About Avicennia Marina

• It is one of the most prominent mangroves species found in all mangrove formations in India.
• It is a salt-secreting and extraordinarily salt-tolerant mangrove species that grows optimally in 75% seawater and tolerates >250% seawater.
• It is among the rare plant species, which can excrete 40% of the salt through the salt glands in the leaves.
• It extraordinary feature is its capacity to exclude salt entry to the roots.

Key highlights of Genome Decoding

• It reports the assemblage of a 456.6 Mb of the estimated 462.7 Mb A. marina genome (98.7% genome coverage) in 31 chromosomes derived from 88 scaffolds and 252 contigs.
• The percentage of genomes in gaps was 0.26%, thereby proving it to be a high-level assembly.
• The A. marina genome assembled can be considered as a reference-grade genome reported so far for any mangrove species globally and the first report from India.
• It identi?ed 31,477 protein-coding genes and a “salinome” consisting of 3246 salinity-responsive genes and homologs of 614 experimentally validated salinity tolerance genes.
• The study reported identi?cation of 614 genes, including 159 transcription factors, which are homologous to the genes that were functionally validated for salinity tolerance in transgenic systems.

About Mangroves

• They are a unique group of species found in marshy intertidal estuarine regions and survive a high degree of salinity through several adaptive mechanisms.
• They only grow at tropical and subtropical latitudes near the equator because they cannot withstand freezing temperatures.
• They are the only trees in the world that can tolerate saltwater, excreting the excess salt through their leaves.

Importance of Mangroves

• They are important resources for the coastal region and are of great ecological and economic value.
• They form a link between marine and terrestrial ecosystems, protect shorelines, provide habitat for a diverse array of terrestrial organisms.
• They stabilize the coastline, reducing erosion from storm surges, currents, waves, and tides.
• They are hotbeds for animal life, both below water and above ground and this biodiversity makes ecosystems more resilient to disease and death.
• They are prolific sequesters of carbon dioxide and are therefore integral for combatting climate change.

Causes of destruction of Mangroves

Shrimp Farming: It is fuelling the clearing of mangrove forests.

• The shrimps are raised in large deposits of waste, bits of feed, pesticides, antibiotics, and chemicals which are often siphoned off or washed out into the ocean, harming neighboring ecosystems.

Sea Level Rise: The rising sea levels, caused by the climate crisis, also pose a significant threat to mangrove forests.

• The rising sea levels wash away mud, depriving mangroves of the soil they thrive in and eventually leading to the mangroves dying from oxygen deprivation.

Invasive Species: They are threatening mangroves and are looking to undermine their ability to regenerate themselves and impact their unique wildlife varieties.