Molecular dissection of the parasitic strategy of the “witchweed”

September 18, 2025

Identification of a molecular target for striga control

A collaborative research group led by scientists at the RIKEN CSRS has identified a genetic mutation that contributes to the distinctive parasitic strategy of Striga, a root-parasitic weed responsible for severe agricultural damage across sub-Saharan Africa. This research is expected to advance the development of new strategies for weakening and controlling Striga.

Striga poses a major threat to crop cultivation in arid regions. Adapted to drought conditions, Striga maintains high transpiration rates by keeping its stomata widely open, thereby efficiently extracting water and nutrients from host plants. This unusual trait is believed to result from Striga’s markedly reduced sensitivity to abscisic acid (ABA), a plant hormone that normally induces stomatal closure to limit water loss. To investigate the molecular basis of this ABA insensitivity, the research group focused on the gene ShPP2C1. Using structural modeling and enzymatic assays, they identified multiple amino acid substitutions that alter the protein’s conformation and reduce its responsiveness to ABA. Among these mutations, a key variant was found to interfere with stomatal closure, thereby sustaining the parasite’s high transpiration flow. These findings could be an effective strategy for controlling this parasitic weed. Moreover, the insights gained from this study may also be applied to crop breeding, such as enhancing stomatal opening to improve CO₂ uptake and photosynthetic efficiency.

 

Original article

Journal of Experimental Botany　doi: 10.1093/jxb/eraf412

S. Katagiri, D. Fukuhara, K. Fujiyama, H. Fujioka, Y. Sugimoto, M. Okamoto,

"Evolutionary and Functional Significance of ShPP2C1 in the Parasitic Life Strategy of Striga".

Contact

Masanori Okamoto; Team Director
Sotaro Katagiri; Postdoctoral Researcher
Keisuke Fujiyama; Special Postdoctoral Researcher
Plant Chemical Genetics Research Team