Strigolactones (SLs) play a crucial role in regulating various aspects of rice plant growth and development (Zheng et al., 2014). DWARF53 (D53) protein (a Clp ATPase) acts as a transcriptional repressor of the genes that function downstream of SL signaling (Jiang et al., 2013). However, the availability of SL leads to the degradation of the D53 protein. In the SL signaling pathway, SLs bind to the SL receptor, DWARF14 (D14), and then SL-bound D14 interacts with the F-box protein DWARF3 (D3). The D3 functions as the substrate recognition subunit of the Skp, Cullin, F-box?containing complex (SCF) E3 ubiquitin ligase, and the D53 protein is a substrate of the SCFD3 ubiquitin ligase complex (Zhou et al., 2013). Thus, in the presence of SL, D53 is tagged for proteasome-mediated proteolysis. The degradation of D53 allows the downstream signaling to proceed, affecting various developmental processes, including lateral branching/tillering, root elongation, leaf angle formation, and response to nutritional deficiencies (Seto and Yamaguchi, 2014). SL interacts with other hormone, such as brassinosteroids and cytokinins, to fine-tune plant growth and development. For instance, SLs and brassinosteroids work together to regulate mesocotyl elongation, while SLs and cytokinins have antagonistic roles in controlling shoot branching/tillering. In rice, SL levels increase in response to nitrogen, Pi, and sulfur deficiencies (Zhang et al., 2024). Likewise, in various plant species, SL levels increase under inorganic phosphate (Pi)-deficient conditions, whereas the application of Pi-containing fertilizers rapidly suppresses SL production and promotes tillering. The mutant phenotypes and additional information are provided in each reaction's summary. The genetic variation and mutation in genes associated with SL signaling affect agronomic traits, such as plant architecture, panicle number, yield, and stress tolerance to biotic and abiotic stressors.
