Evolution of Strigolactone Biosynthesis and Signalling

Abstract

Studying evolutionarily primitive organisms with simpler genomes can provide information about the core genetic machinery required for any biological process, including hormone production and perception. In this chapter, we present findings on strigolactone biology based on work with two model byrophytes, the moss Physcomitrella patens and the liverwort Marchantia polymorpha. We summarise the existing knowledge of strigolactone biosynthesis in primitive plants, and discuss the role of strigolactones in regulating growth in response to competition from neighbouring plants.We then turn to strigolactone perception and signal transduction, with a focus on the diversity among putative strigolactone receptors in the KAI2/DWARF14 family of α/ β-hydrolases. We speculate on the “original” role for strigolactones for early land plants as a rhizosphere signal, before they were adopted as hormones to regulate development. Finally, we summarise discoveries that explain how strigolactones released by plant roots came to be exploited as germination signals by root-parasitic weeds.