Poly(A)-binding proteins promote rac-GR24-induced seed germination of the root-parasitic plant Phelipanche ramosa and Arabidopsis thaliana

Phelipanche ramosa , an obligate parasitic plant from the Orobanchaceae family, significantly impacts crop productivity across Mediterranean and warm temperate areas of Europe, North Africa, and Middle East. Since seed germination marks the critical entry point into the parasitic lifecycle, unraveling its molecular regulation is key to developing effective control strategies. Previous transcriptome analysis of seeds of the closely related species P. aegyptiaca treated with the synthetic strigolactone (SL) analog, rac -GR24, identified genes associated with mRNA translation as key players in seed germination. This study explores the role of poly(A)-binding proteins (PABs), central regulators of mRNA stability and translation efficiency, in the germination process of P. ramosa and the model plant Arabidopsis thaliana . The results demonstrate that PrPAB transcript levels in P. ramosa seeds and the PrPAB protein levels expressed in A. thaliana are responsive to rac -GR24. In A. thaliana , which germinates in response to karrikins (KARs) via a mechanism analogous to SL-induced germination, both shared and species-specific features of AtPABs were observed. Our findings highlight a broader role for PAB proteins influencing not only rac -GR24-induced seed germination but also early seedling development.