Deep-sea hydrothermal vents spew out metal-laden plumes, enveloping their vicinity in heavy metals like iron and manganese. These metals, at high concentrations, can become lethal. Despite these perilous conditions, a myriad of organisms form thriving ecosystems adjacent to these vents, demonstrating a remarkable resilience against the metallic threats.
Researchers have now delved into understanding how one specific creature, the sea anemone Alvinactis idsseensis, endures in this metal-rich environment. They found that the anemone possesses an unusually high number of genes designed to create proteins that safely relocate these metals within their cells, rendering them harmless. Their findings were documented on October 20 in Science Advances.
While most organisms, including certain shallow-water sea anemones, possess a few Metal Tolerance Protein (MTP) genes vital for standard metal metabolism, A. idsseensis boasts an impressive 13 MTP genes, as discovered by marine biologist Haibin Zhang and his team.
These specific sea anemones are abundant in the Edmond and Kairei vent fields situated in the southwest Indian Ocean. Not only is A. idsseensis the predominant species in these vent terrains, preying on blind shrimps, but their resilience and adaptation to such harsh conditions have always been a matter of scientific curiosity.
This enigma was partly unraveled when Zhang’s team decoded the genome of an anemone specimen from the Edmond vent field, collected in 2019. When two of the most active MTP genes from this anemone were genetically integrated into yeast, the yeast exhibited heightened resistance against toxic concentrations of iron and manganese – the predominant metals in that environment.
Interestingly, this strategic proliferation of MTP genes, a method for metal detoxification, is also observable in specific plants. The mustard plant Arabidopsis halleri, for instance, flourishes in zinc-abundant soils and possesses a greater count of MTP genes than its metal-sensitive counterparts.
This shared trait between sea anemones and certain plants is believed to be a manifestation of “convergent evolution”, where analogous environmental stressors shape similar adaptive solutions in unrelated species.
While the research has made substantial strides in understanding the metal detoxification mechanisms in these anemones, the exact modus operandi of their MTP genes remains a puzzle. In plants, these genes typically transport metals to expansive cellular units named vacuoles. However, such vacuoles are absent in animal cells, leading to further intrigue on their detoxification processes.
This unfolding mystery presents exciting avenues for future exploration in marine biology.