Strigolactone biosynthesis, transport and perception.

Strigolactones (SLs) are plant hormones that regulate diverse developmental processes and environmental responses. They are also known to be root-derived chemical signals that regulate symbiotic and parasitic interactions with arbuscular mycorrhizal fungi and root parasitic plants, respectively. Since the discovery of the hormonal function of SLs in 2008, there has been much progress in the SL research field. In particular, a number of breakthroughs have been achieved in our understanding of SL biosynthesis, transport and perception. The discovery of the hormonal function of SL was quite valuable not only as the identification of a new class of plant hormones, but also as the discovery of the long-sought-after SL biosynthetic and response mutants. These mutants in several plant species provided us the genetic resources to address fundamental questions regarding SL biosynthesis and perception. Such mutants were further characterized later, and biochemical analyses of these genetically identified factors have uncovered the outline of SL biosynthesis and perception so far. Moreover, new genes involved in SL transport have been discovered through reverse genetic analyses. In this review, we summarize recent advances in SL research with a focus on biosynthesis, transport and perception.