International Collaboration Finds Land Plant Genes in Ancient Aquatic Alga

College of Computer, Mathematical, and Natural Sciences

Newly sequenced algal genome shows that adaptations essential for land plants evolved before land plants didLand plants, which split from their aquatic relatives 500 million years ago, are an extraordinarily diverse group of living organisms—from tall redwoods to fragrant roses to carpets of moss.
For plants, survival on dry land required some new evolutionary innovations. For instance, they had to develop root systems that can absorb nutrients from soil. They also needed strong stems that can support their own weight without help from the buoyancy of water. Land plants evolved to deal with these and many other environmental challenges, resulting in their worldwide abundance today.
To better understand the genetic adaptations that made this transition so successful, an international team, which included three University of Maryland researchers, sequenced and analyzed the genome of Chara braunii, a freshwater green alga closely related to land plants. By comparing Chara’s genome to multiple land plant genomes, the team was able to identify many important genes that originated in a common ancestor shared by Chara and land plants. 
The research paper was published in the journal Cell on July 12, 2018.
“It’s great to finally have a genome from an alga closely related to land plants,” said UMD Cell Biology and Molecular Genetics Professor Charles Delwiche, an expert in plant evolution. “This information will help us understand which land plant functions were truly novel.” 
Chara braunii belongs to a division of plants called Charophytic algae, which are the closest living relatives of land plants. As one of the first Charophytic algae to have its genome sequenced, Chara has yielded important information on how land plants evolved from their aquatic ancestors.
“Our data show that a number of genes previously considered typical for terrestrial plants can already be found in these algae,” said Stefan Rensing, a professor of cell biology at the University of Marburg …

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