Parasitic weeds have long been a nightmare for farmers across the globe, voraciously siphoning off nutrients from vital crops and leading to devastating losses in harvests. However, groundbreaking research from scientists at UC Riverside presents a game-changing strategy that could compel these relentless invaders to destroy themselves.

In regions of sub-Saharan Africa and parts of Asia, where food insecurity is a pressing issue, entire harvests of staple crops, such as rice and sorghum, are at risk due to an army of parasitic weeds. Farmers have been left largely defenseless against these pests, with few effective methods available for control. But researchers at UC Riverside believe they have found a way to turn the biological mechanisms of these weeds against them.

The innovative technique, outlined in the journal Science, hinges on the use of strigolactones—a class of hormones that serve dual functions in plants. Internally, strigolactones assist in growth regulation and stress responses to environmental factors such as drought. Externally, however, they play an unusual role. According to UCR plant biologist and study co-author David Nelson, "Most plant hormones remain internal, but these hormones are aware of their surroundings." Plants release strigolactones to attract symbiotic fungi in the soil, fostering beneficial relationships.

Sadly for farmers, parasitic weeds have learned to exploit these chemical signals, using them as cues to invade crops. Once these invaders detect strigolactones, they germinate and latch onto the roots of their host plants, draining the essential nutrients needed for growth.

Nelson reveals the crux of this research: "These weeds are waiting for a signal to wake up. If we can provide that signal at an inappropriate time—when they have no suitable host—they will sprout and perish." This ingenious method essentially encourages the unwanted weeds to self-destruct.

To tackle the complexities surrounding strigolactone production, the research team led by Yanran Li, now at UC San Diego, developed a cutting-edge system utilizing engineered bacteria and yeast. By fashioning these microorganisms into miniature chemical factories, researchers were able to recreate the intricate biological processes involved in producing strigolactones. This achievement not only advances the understanding of how these hormones are synthesized but could also pave the way for substantial production of these vital chemicals.

The team also investigated the enzymes involved in strigolactone production, pinpointing crucial metabolic pathways that have contributed to the evolution of these hormones from internal regulators to external signaling agents.

“This is a powerful system for investigating plant biochemistry,” said Nelson, adding that it allows for the characterization and manipulation of previously unstudied genes that influence strigolactone production.

In addition to its agricultural implications, the research on strigolactones reveals exciting potential for medical and environmental applications. Some initial studies suggest these hormones could offer anti-cancer and anti-viral properties, and there’s ongoing research into their effectiveness against Citrus greening disease, which has devastated citrus crops in Florida.

Despite the promising results from laboratory settings, scientists must still determine the practicality of implementing this strategy in real-world agricultural fields. "We're currently fine-tuning the chemical signals to enhance their effectiveness," Nelson stated. Success in this endeavor could revolutionize farming practices, providing crucial support for farmers battling these parasitic threats.

The pioneering work is led by eminent UCR professor and geneticist Julia Bailey-Serres, whose contributions to this field of research could ultimately reshape the future of sustainable agriculture and food security in vulnerable regions worldwide.