Scientists use plant hormone weapons to deceive parasitic weeds to die early

In the harsh farmlands of sub-Saharan Africa, every harvest could mean the difference between parasitism and hunger, a silent battle erupted under the soil. Parasitic weeds (parasitic weeds are ruthless freeloaders) have long been jeopardizing critical food crops before they can be drained before they can be properly grown. Now, UC Riverside researchers have discovered a seemingly simple strategy that can give farmers a chance to fight: to deceive these agricultural vampires to “take suicide.”

The technology details a class of unique phytohormones called strainoctones in the Jan. 17 journal Science, which exhibits unusual behavior that most phytohormones cannot be shared.

“For the most part, plant hormones don’t irradiate outside – they are not emitted. But these.” “Plants use strainoctones to attract fungi in soils that have beneficial relationships with plant roots.”

This external signaling has been hijacked by invasive parasitic weeds that use strainolactones as chemical beacons indicating a potential host nearby. The seeds of weeds can sleep in the soil for many years, waiting for the signal before germination and attachment to crop roots.

The UCR team’s insights are very cruel in terms of simplicity: using weeds to their biology.

“These weeds are waiting for the signal to wake up. We can signal them at the wrong time – when there is no food – so they sprout and die,” Nelson said. “It’s like turning their own transformation to them, essentially encouraging them to commit suicide.”

In areas where food is not secure in parts of Africa and Asia, farmers watch helplessly because these parasites consume staples such as rice and sorghum. The traditional method of fighting these weeds is largely ineffective, because the parasites have built their own underground before the farmers even realize they have been invaded.

To better understand the production of Stregoone, a research team led by Yanran Li (formerly at UCR and now at UC San Diego) has developed an innovative system that turns common microorganisms into hormone factories. By engineering E. coli and yeast cells to produce these chemicals, they recreate the biological pathways required for hormone synthesis in a controlled environment.

This approach not only helps researchers understand how hormones work, but can also lead to cost-effective methods to produce large quantities of these valuable chemicals for field applications.

The group also made progress, identifying a key metabolic branch point in understanding the enzymes responsible for producing strigolactone, which seems crucial in the evolution of these hormones from internal plant regulators to external signaling molecules.

“It’s a powerful system for studying plant enzymes,” Nelson noted. “It allows us to characterize genes that have never been studied before and manipulate them to understand how they affect the types of strainolactones being made.”

Although the main focus is on agricultural applications, these findings may have broader implications. Some studies have shown that strolonone may have the potential of anticancer drugs or antiviral drugs. Their possible role of combating citrus green disease has also attracted interest, which is currently causing the citrus industry in Florida.

This work is due to growing concerns about global food security, and climate change is expected to exacerbate the challenges of global agricultural production. Student researcher Annalize Kane is the co-first author of the study, representing the next generation of scientists to solve these problems.

The study was supported by UCR’s NSF-funded Plant 3D Training Program, led by distinguished professor and geneticist Julia Bailey-Serres.

“The program is very exciting because it can help students learn to use cutting-edge technology to increase crop yield and nutritional value, while also helping themselves professionally,” Bailey-Serres said.

The realistic application of the “weed suicide” strategy remains an open question. The team is continuing to refine their approach before field testing.

“We are testing whether the chemical signal can be fine-tuned to make it more effective,” Nelson said. “If it can, this could change the game for farmers fighting these weeds.”

For farmers struggling in developing countries as a whole, this innovation cannot be fast. As the global population continues to rise and cultivated land becomes increasingly scarce, finding sustainable ways to fight agricultural pests has never been more urgent. By targeting the parasitic plants’ own signaling system, these researchers may have discovered an elegant solution hidden in a flat line of sight, the biology of the plants themselves.