Host Specificity and Germination Stimulants of Phelipanche aegyptiaca Parasitizing Solanaceous and Leguminous Crops

Abstract

Phelipanche aegyptiaca is a destructive holoparasitic weed that severely affects the productivity of numerous agricultural crops, particularly solanaceous and leguminous species. The parasite causes substantial economic losses by attaching to host roots and extracting water, nutrients, and photosynthates required for plant growth and development. Successful parasitism of P. aegyptiaca largely depends on host specificity and the presence of germination stimulants released by host plant roots. The present study was conducted to evaluate the host specificity and germination responses of P. aegyptiaca seeds to root exudates from selected solanaceous and leguminous crops. Laboratory and greenhouse experiments were performed using root exudates collected from different crop species to determine their effects on seed germination, haustorial initiation, and parasite attachment. Germination bioassays were conducted under controlled conditions, and germination percentages were recorded following exposure to host-derived stimulants. The results demonstrated significant variation in the ability of different crop species to induce germination of P. aegyptiaca seeds. Solanaceous crops exhibited stronger stimulatory effects on seed germination and parasite development compared with several leguminous crops, indicating differences in the composition and concentration of root-derived signaling compounds. Certain host plants promoted high germination rates and successful parasitic attachment, whereas others exhibited relatively lower susceptibility to infection. The findings suggest that host specificity in P. aegyptiaca is closely associated with the release of chemical germination stimulants in root exudates. Understanding these host–parasite interactions provides valuable insights into the ecology and management of parasitic weeds in agricultural systems. The study highlights the importance of identifying resistant or less stimulatory crop species for use in integrated management strategies aimed at reducing the spread and impact of P. aegyptiaca in economically important cropping systems.