Outsmarting Nature with Science to Improve Food Security

At first glance, Striga hermonthica, appears to be an attractive plant with delicate purple flowers, but in reality, it plays the starring role in a botanical horror story. Striga hermonthica, also called purple witchweed, and other root parasitic plants act like a blood-sucking leech underground, their roots starving nearby host plants of essential nutrients. By the time these young parasitic seedlings rear their heads, the damage is done, and entire crops are often decimated. This is a devastating problem for many farmers in hot and arid regions around the world. Professor Salim Al-Babili at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia says, “Striga is considered to be one of the major threats to global food security. It affects the productivity of cereals in Africa causing severe losses. I’m guiding an international consortium, funded by the Bill & Melinda Gates Foundation, to combat this root parasitic weed.”

Salim points to the support he receives at KAUST, its world-class facilities, and collaborations with top-tier scientists both in the university and abroad as being fundamental to the success of his research. KAUST has several multidisciplinary state-of-the-art laboratories on the university’s campus called core labs that have been essential for his work. He says, “In terms of my basic science work, I believe it wouldn’t have been possible if I were not at KAUST, because I have the freedom, funding, and resources to carry out my research. At KAUST, if you have a good idea, you can really test your hypothesis. You can do what might be difficult at other places.”

Much of Salim’s distinguished career has been spent working on issues of major global importance. Just over 20 years ago, he was part of the team that used genetic engineering to create golden rice.  “Vitamin A deficiency is still a severe health problem globally, and a major reason for childhood mortality,” he explains. “Golden rice contains a high level of pro-vitamin A, and now after 20 years, it’s being grown in fields.” This work cemented his interest in plant metabolic engineering, which involves manipulating a plant’s internal chemical pathways to produce a desirable outcome.

Salim’s current research at KAUST is just as far-reaching and consists of both basic and applied science. “In my basic science research, my team and I try to understand metabolic pathways in plants, for instance, the biosynthesis of hormones, and to identify new growth regulators that affect different aspects of plant growth, resilience, and productivity. Then, we look for possibilities to translate what we discovered in our basic science research into application. We also use genetic engineering or gene editing approaches to produce plants with higher productivity or greater resilience.” Recently, they characterised a presumed new plant hormone called zaxinone that can boost rice productivity and promises to be a key growth regulator for many different cereals.

Salim’s work on Striga stems from his basic research. He was initially interested in the biosynthesis of a plant hormone called strigolactone. This is released by the roots of plants and triggers the awakening of dormant Striga seeds in the soil.  He explains, “Our Striga project has three parts. In the first part, we want to develop and establish the Suicidal Germination technology to clean off infested soils. This technology makes use of the dependence of Striga on host plants and is based on inducing germination of Striga seeds by applying hormone analogues in the absence of the host plant, which causes the death of the arising seedlings. In the second part, we develop novel chemistries that either promote the growth of the host and disrupt its interaction with Striga or inhibit Striga seed germination [Striga-specific herbicides]. The third part focuses on genomic and gene editing and understanding the genetic background of resistance and susceptibility in pearl millet.” For this last part, Salim’s team is trying to establish molecular tools for this nutrient-rich cereal that’s widely grown in arid and hot zones. This will help generate Striga-resistant varieties and improve the resilience and productivity of this important cereal.

Salim moved to KAUST from Germany in 2013 and enjoys life in the small community around the university. It takes him under 10 minutes to cycle from his home to his office. He loves the beautiful weather in the winter months and mentions an array of outdoor activities available to people living there, like playing tennis and snorkelling or diving in the Red Sea. Jeddah, the country’s second-largest city, is also just one hour away by car. “KAUST is a global village for science,” he says. “The whole environment is a scientific one, and that's something I enjoy. I work with nice colleagues, with open-minded people who often have time for discussions. I appreciate the fact that work at KAUST can have an impact, and that you can realise things here that cannot be realised elsewhere.”