ストリゴラクトンの二面的機能，その起源と進化

抄録

Strigolactones (SLs) were first identified as compounds that are exudated from roots, inducing seed germination of parasitic plants and hyphal branching of arbuscular mycorrhizal (AM) fungi. Later, SLs were identified as a class of plant hormones that regulate plant growth and development. Thus, SLs play dual functions as hormones and rhizosphere signaling molecules. This remarkable feature makes SLs unique among plant hormones. In addition, the diversity of structures is another unique feature of SLs. Recently, a novel SL has been identified from bryophytes and named bryosymbiol (BSB). BSB is also present in ferns and seed plants, indicating it is likely to be the ancestral SL that originated in the common ancestor of land plants. BSB is required for symbiosis with AM fungi in Marchantia paleacea, a bryophyte, while it does not seem to play a role in controlling growth and development. These findings indicate that the SLs originated as rhizosphere signaling molecules, and thefunction of SLs as plant hormones established later after the occurrence of D14, the SL receptor in the evolution of vascular plants.