TED1 Promotes the Assembly of SCF D3 ‐D14‐D53 to Reinforce Strigolactone Signaling in Rice

ABSTRACT Strigolactones (SLs) are a class of terpenoid lactone hormones that repress plant branching, such as tillering in rice. In rice ( Oryza sativa L.), SLs promote the assembly of the SCF D3 ‐D14‐D53 complex, which triggers the ubiquitination and degradation of the SL signaling repressor D53, thereby activating downstream responses. Here, we identify TED1, a scaffold subunit of the SWR1‐like chromatin remodeling complex, as a critical positive regulator of SL signaling that facilitates the assembly of the SCF D3 ‐D14‐D53 complex. The ted1 mutants exhibit reduced sensitivity to the SL analogs 5‐deoxystrigol (5DS) and rac ‐GR24, resulting in increased tillers and dwarfism. We demonstrate that TED1 interacts with D53 independently of SLs and with D14 to enhance the interaction between D14 and D53 or D3 in a SL‐dependent manner, thereby efficiently promoting the ubiquitination and degradation of D53. Furthermore, we show that beyond its canonical role in chromatin remodeling function, the C‐terminal extension of TED1 homologs has evolved a new key function in reinforcing SL signaling, which may represent a key innovation underlying the enhancement of apical dominance in higher plants.