This research has implications for designing entirely new plants that are optimised for specific functions.

A multi-investigator effort led by scientists from the Salk Institute has recently reported new findings about the plant’s genome that explain how it’s able to grow so fast. The research, published in the February 2021 issue of Genome Research, will help scientists to understand how plants make trade-offs between growth and other functions, such as putting down roots and defending themselves from pests. This research has implications for designing entirely new plants that are optimized for specific functions, such as increased carbon storage to help address climate change.

“A lot of advancement in science has been made thanks to organisms that are really simple, like yeast, bacteria and worms,” says Todd Michael, first author of the paper and a research professor in Salk’s Plant Molecular and Cellular Biology Laboratory. “The idea here is that we can use an absolutely minimal plant like Wolffia to understand the fundamental workings of what makes a plant a plant.”

Wolffia, also known as duckweed, is the fastest-growing plant known and is found growing in fresh water on every continent except Antarctica, looks like tiny floating green seeds, with each plant only the size of a pinhead. It has no roots and only a single fused stem-leaf structure called a frond. It reproduces similar to yeast, when a daughter plant buds off from the mother.

To understand what adaptations in Wolffia’s genome account for its rapid growth, the researchers grew the plants under light/dark cycles, then analyzed them to determine which genes were active at different times of the day.

The researchers also found that genes associated with other important elements of behavior in plants, such as defense mechanisms and root growth, are not present. “This plant has shed most of the genes that it doesn’t need,” Michael adds.