KAUST Researchers Identify Gene That Improves Pearl Millet's Resistance To Parasitic Weeds

A recent study from King Abdullah University of Science and Technology (KAUST) has identified a crucial gene affecting crop resistance to Striga hermonthica, a parasitic weed threatening global agriculture. Pearl millet, a staple in Saudi Arabia and other arid regions, is particularly susceptible. Researchers discovered that pearl millet strains lacking the CLAMT1b gene showed resistance to this weed, offering insights into breeding strategies for enhanced food security.

Striga hermonthica, also known as purple witchweed, attaches to host plants like pearl millet to extract water and nutrients. This parasitic interaction can be blocked either through an immune response or by manipulating hormone levels. The study revealed that the presence of the CLAMT1b gene in pearl millet leads to the production of strigolactones, hormones that facilitate Striga's attachment.

Pearl millet is vital for nearly 100 million people in Africa and Asia, especially in dry areas. Its resilience to heat and drought makes it crucial for food security. The United Nations has recognised its importance by declaring 2023 as the International Year of Millets. The findings from KAUST could significantly impact breeding programs aimed at enhancing crop resistance.

The research involved examining the genomes of two pearl millet lines. It was found that those expressing the CLAMT1b gene secreted four types of strigolactones, promoting interaction with Striga. Conversely, lines without this gene were resistant to the weed. This discovery suggests that removing CLAMT1 genes could protect crops without disrupting beneficial ecological relationships.

Further analysis showed that many pearl millet varieties, including commercial ones, express the CLAMT1b gene. However, this gene does not affect the plant's symbiotic relationship with arbuscular mycorrhizal fungi. These fungi enhance water and nutrient uptake and provide disease resistance, indicating that removing CLAMT1 genes won't harm these beneficial interactions.

"Our study should assist plant breeders in selecting seeds with the resistant allele," stated KAUST Professor Salim Al-Babili. "More resistant cultivars for both commercial farms in Saudi Arabia and smallholder farmers in Africa would greatly improve food security in these regions." This research was supported by the Bill and Melinda Gates Foundation and published in Nature Communications.

With inputs from SPA