Genetic and ecophysiological bases of Striga resistance in sorghum
Plant Biology Seminar Series

  February 9, 2026 @ 12:15 pm to 01:15 pm

  108 Wartik
  University Park

The parasitic weed Striga hermonthica is a devastating threat to African cereal production, causing up to 100% yield loss in hosts like sorghum, maize, rice and millets. Striga’s lifecycle is governed by chemical signaling, germinating only in response to host-derived strigolactones (SLs) and forming the haustorium upon sensing host-derived haustoria inducing factors (HIFs). In this seminar, we discuss how natural and induced mutations impact distinct stages of the sorghum (Sorghum bicolor) defense system. A natural deletion of the LGS1 gene drives functional diversity in global sorghum by rerouting the SL biosynthesis pathway and creating a gap in parasite perception. Conversely, point mutations in the monolignol biosynthesis pathway modulate resistance following sorghum’s physical contact with the parasite. While cognizant of the negative pleiotropic effects often associated with loss-of-function mutations in specific environments, we explore how cis-regulatory variants could modulate gene expression and potentially confer durable resistance without compromising agronomic performance. Finally, we position these mechanisms within the context of landscape-scale variation and local adaptation. We also analyze the interaction between pre- and post-attachment defenses, and ask whether this resistance architecture provides generalized or ecotype-specific protection. Resolving the evolutionary trade-offs that maintain these traits is essential for designing Striga-adaptive strategies and anticipating future dynamics under shifting selective landscapes.

About the Speaker:

Joel Masanga is a Postdoctoral Scholar in Jesse Lasky’s Group at Penn State University, where he leads the Striga trait discovery in sorghum on the Allele Mining Project. A native of Kakamega, Western Kenya, Joel brings a deep, region-specific understanding to the challenges of parasitic weeds in Africa. Joel holds a Master’s degree in Plant Biotechnology from Jomo Kenyatta University of Agriculture and Technology and a Ph.D. from Kenyatta University. His doctoral research at Kenyatta University focused on the ecology and genomics of another pervasive parasitic plant genus, Cuscuta, with his dissertation titled: "Taxonomy, distribution and host range of Cuscuta species across Kenya ecosystems." Since joining the Lasky lab in 2022, Joel’s research has been dedicated to the discovery and validation of genetic factors conferring resistance and tolerance to the devastating parasitic weed, Striga hermonthica, in sorghum. His work extends to investigating the genetic variation of Striga itself, specifically how the parasite has evolved its ability to sense host-derived chemical signals. This research aims to provide critical data to guide the development and deployment of effective, durable control strategies for smallholder farmers.

Fun Fact: Joel has recently developed a strong passion for football, recognizing many parallels the game has with complex host-parasite dynamics—from signaling and blocking to high-stakes 'penalties'.

Contact

  Jesse Lasky
  jrl35@psu.edu