The food and fuel that farms itself

(Press-News.org) Under the right conditions, duckweed essentially farms itself. Wastewater, ponds, puddles, swamps—you name it. If there’s enough sunlight and carbon dioxide, the aquatic plant can grow freely. But that’s not all that makes it intriguing. Packed inside duckweed’s tiny fronds is enormous potential as a soil enricher, a fuel source, protein-rich foods, and more. New findings at Cold Spring Harbor Laboratory (CSHL) could help bring all that potential to life.

CSHL Professor and HHMI Investigator Rob Martienssen and Computational Analyst Evan Ernst started working with duckweed over 15 years ago. They see their latest research as one of the most important and eye-opening studies on the plant to date. The team has developed new genome sequences for five duckweed species. The sequences reveal several genes that—when present or absent—may be behind the plant’s unique traits and versatility. Martienssen explains:

“The use of cutting-edge technology allowed us to make a catalog of genes that was extremely accurate. We could tell exactly which genes were there and which were not. A lot of genes that are missing are responsible for features of the plant—open stomata or the lack of roots. We could identify genes that were responsible for each trait.”

Stomata are pores on the surface of plants. They’re crucial for taking in carbon dioxide and releasing oxygen. Open stomata allow for greater intake, making them valuable for carbon capture technology. A lack of roots in some species further increases duckweed’s potential, making it easier for the plant to thrive in any watery environment.

Other species possess traits that showcase duckweed’s potential as a food and fuel source. Some traits promote high protein production, allowing for use as animal feed. Others promote starch accumulation, making the plant ripe for biofuel production. Several industries have taken notice. For now, they’re mostly concerned with the duckweed growing in their backyards. Ernst explains:

“Duckweed agriculture is in a nascent stage. Commercial growers are working with different species in the field, evaluating them in their own local situation. There’s so much variation within one species of duckweed—as much as you can find across all the species. So, having multiple genomes for multiple species is critical.”

Martienssen and Ernst hope their genomes will open the door to a new world of commercial applications. That said, their research may tell us as much about the plant’s past. Their study hints at how duckweed split off into different species 59 million years ago. Earth’s climate was quite extreme back then, so duckweed’s genes just might say something about the planet’s future, too.

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