GLO-Roots opens path to stronger drought tolerance
Shoots and roots are separated by the horizon line, but scientists are chasing a firefly trail into a mysterious and underexplored world. Researchers have long been blocked from peering down into the subterranean realm of plant roots. Yet, a new imaging system uses firefly bioluminescence to peek inside the black box of root growth.
GLO-Roots, a new tool developed by the Carnegie Institution of Science, enables researchers through bioluminescence. The system reveals how root decisions are affected by stresses directly related to agriculture. Essentially, GLO-Roots can peel back the curtain on vital agronomic questions: How do plants survive during drought?
Current methods for root observation are hindered by artificial environments that don’t reflect true growth conditions. These methods expose roots to light, causing anomalous behavior from natural field conditions. Plus, roots behave differently according to soil type, microbes, bacteria and a host of additional factors. It’s near impossible to consistently observe normal root behavior.
GLO-Roots uses a firefly gene to reveal root behavior and better determine how plants survive drought.
Enter GLO-Roots or Growth and Luminescence Observatory for Roots. Plants are grown in special boxes; cameras record the glow of hidden plant growth; and root behavior is revealed. “We want to know how growth is affected by resources vital to farmers—water and nutrients,” says José Dinneny, research leader at Carnegie. “What we ultimately want is agriculture that uses fewer inputs. When we understand how root systems find water and nutrients, it’ll lead to real improvements in crops.”
Dinneny’s custom built root boxes are 12" deep and 6" wide and made of transparent plastic. His team inserts a firefly gene into Arabidopsis mustard plants, and when watered with luciferin as a chemical trigger, the light show in the roots begins. Luciferin is not harmful to the plants and typically glows for a week. The roots don’t glow at an observable level in a darkened room. Specialized CCD cameras count the photons emitted by the glowing roots and watch what the human eye misses.
Luciferin enzymes can emit different colors and allow Dinneny to track multiple growth functions. “We can use a particular color to track which parts of the root system are experiencing drought and other colors to track different biological processes,” he says.
For the first time, root behavior is observable during drought. The technology is a research game-changer, Dinneny says. If science can identify the genes necessary to control a plant’s ability to grow toward water, the same gene strategies can be employed in field crops. “We want to identify the genes responsible for gathering water or nutrients and then manipulate or breed for heartier plants,” he says.
The Carnegie team is adding a robotic system to water plants and move them into the imaging system without human interference.
While the framework of GLO-Roots technology is provided in an open-access manner, Carnegie has patented the core of the GLO-Roots method and licensed it to i-Cultiver, a company developing naturally beneficial biological treatments for applications in agriculture and food.
“What’s patented is the glowing root part of the plant and the imaging process with a CCD camera,” says Rajnish Khanna, CEO, i-Cultiver. “GLO-Roots has two very exciting applications for agriculture. One is through drought tolerance. A second involves observing bacteria to reduce plant disease. We’re in the discovery phase and expect commercial availability in one to two years.”
“The study of these model plant roots is crucial toward identifying the key mechanisms and genes in growth,” Dinneny adds. “When we’ve uncovered those answers, we’ll move right into crops.”