Mozuku is a unique Okinawan seaweed. Scientifically known as Cladosiphon okamuranus, this alga is popular in Japanese cuisine, and it has been farmed for more than 35 years.
The cultivation of this seaweed is a key element in the economy of Okinawa but, in 2015, production dropped due to higher ocean temperatures.
Helping to preserve the sea weed, Koki Nishitsuji, Asuka Arimoto, Noriyuki Satoh and Eiichi Shoguchi, from the Marine Genomics Unit of the Okinawa Institute of Science and Technology Graduate University (OIST), led the decoding of the DNA of a specific strain of Okinawa mozuku - the S-strain.
The scientists carried out the examination of the mozuku's genetic code comparing their results with related published studies. This approach grounded the findings of the study in the wider landscape of the genetic studies of seaweeds, assuring the relevance and precision of the results.
Knowing its DNA - that is made by 13,640 genes - the researchers now have the possibility of developing a comprehensive and well-informed approach to the protection, growth and scientific understanding of mozuku.
"Our study provides a platform for future studies of Okinawa mozuku," Shoguchi said. "It represents the first step in understanding the organism in itself."
The first way in which the genetic information of the seaweed can be used is to develop a variety of mozuku that can thrive in hotter waters.
"After obtaining this first genome, it will be easier to compare the different strains," Nishitsuji explained.
"It will be then possible to develop a more resistant variety of mozuku." Such a variety of alga could restore the production levels, thus effectively helping the fishermen in their struggle against the present drop in seaweed production.
Mozuku has important health properties, because it is a natural source of fucoidan. High levels of this unusual molecule are found in mozuku, and it has unique tumour-suppressant and anti-coagulant properties. Ensuring consistent production levels of mozuku would allow widespread consumption of this healthy seaweed, which is already present in food supplements and has shown anti-cancer characteristics during laboratory tests.
The data found in this study will be an important step in the interpretation of the evolution of brown algae. Mozuku is one of the members of this family of seaweeds, which play a key role in the ecology of the ocean.
"Brown algae are also called 'seaweed bed' or 'underwater forest', and several marine organisms use these algae as a nesting place," Nishitsuji said.
"Having full access to the Okinawa mozuku's DNA will help in clarifying the evolutional strategy of the brown algae and its relationship with the surrounding environment."
Finally, mozuku has a unique texture and flavour, which is sought after by culinary enthusiasts. The secret of this specific taste is inside the mozuku's DNA, and it could be now possible to understand which part of the genetic code is responsible for it.
