Action of strigolactones in plants

Strigolactones (SLs) have diverse roles that afford plants robust adaptive capacities to interact with diverse growth environments. Based on recent progress in the characterization of a class of SLs-insensitive shoot branching mutants, key components of the SL signal transduction pathway have been identified, and a framework of SL actions in plant development is emerging. The ubiquitin-proteasome system-mediated target protein turnover is an integral component in SL signaling, as is the case with other plant hormone signaling pathways. Although the detailed ligand perception mechanism and the downstream events of SL signaling still remain illusive, it has been shown that SLs can act as communication molecules to coordinate internal developmental programs and regulate diverse plant responses to the external environments. Here, we review our current understanding of the molecular mechanism that underlies SL signaling, mainly focusing on the role of SLs in shoot branching and the comparison with other plant hormones in an effort to highlight the unique characteristics of SL signaling and action in plant growth and development.