Sequencing of the nuclear genome of Porphyra umbilicalis — laver or Atlantic nori — has revealed insights into how the bangiophyte red algae have thrived for over a billion years in the harshest environmental conditions — the pounding waves, baking sun and drying winds of the intertidal zone.
An international research team of 50 scientists led by Susan Brawley, professor of marine sciences at the University of Maine, discovered ancestral mechanisms of cell wall formation, an array of ultraviolet/high light and thermal protection strategies, and a wealth of nutrient transporters encoded by the P. umbilicalis genome.
The analysis of the Porphyra genome and the team’s comparative analysis to available nuclear genomes of other red algae revealed novel features, including a reduced complement of motor proteins, unique signaling molecules and augmented stress tolerance mechanisms. The unexpected findings, published in the Proceedings of the National Academy of Sciences, offer a potential explanation for why the red algae are constrained to small stature relative to other multicellular lineages. Researchers discovered that the cytoskeleton that is so central to growth, development and ability to respond to environmental signals in most organisms has a strikingly small number of elements in Porphyra and other red algae.
Major support for the sequencing was provided by a contract from the Joint Genome Institute of the U.S. Department of Energy and by grants from the National Science Foundation.
Porphyra attains high biomass despite the high levels of stress in its habitat in the upper intertidal zone of the North Atlantic, such as low tide at Sand Beach, Acadia National Park, Maine. Laver is a human food, and is being developed as an aquaculture crop by marine sciences professor Susan Brawley and her team at the University of Maine. The completed genome provides insights to its nutritional value, especially to its content of minerals, such as iron and vitamin C; vitamin E; and B vitamins, including B12.