Strigolactone Regulation of Rice Shoot Branching and Plant Architecture Revealed

Strigolactones (SLs) are a group of plant hormones that control plant shoot branching. They play a significant role in plant architecture regulation, but their signaling mechanisms have been poorly understood. 

A joint research team from the Institute of Genetics and Developmental Biology and the Shanghai Institute of Materia Medica, both of the Chinese Academy of Sciences, has reported the characterization of dominant SL-insensitive rice (Oryza sativa) mutant dwarf53 (d53) and the cloning of D53, which encodes a substrate of the SCFD3 ubiquitination complex and functions as a repressor of SL signaling. 

The study was published in Nature.

Induced by SL signaling, the D53 protein can form a complex with DWARF 14 (D14, a SL receptor) and the F-box protein DWARF 3 [D3, an F-box component of the Skp1–Cullin–F-box (SCF) E3 ubiquitin ligase complex], two previously identified signaling components potentially responsible for SL perception, which causes D53 degradation.

In a D14- and D3-dependent manner, SLs induce D53 degradation and regulate plant architecture, whereas the dominant form of D53 is resistant to SL-mediated degradation. 

Another independent study, also published in Nature, came to the same conclusion. It was conducted by researchers from Nanjing Agricultural University, the Chinese Academy of Agricultural Sciences, and the University of Washington. 

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