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Fellowship of the rings: a saga of strigolactones and other small signals
Author(s) -
Machin Darren C.,
HamonJosse Maxime,
Bennett Tom
Publication year - 2020
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.16135
Subject(s) - strigolactone , signalling , signalling pathways , biology , function (biology) , computational biology , mechanism (biology) , evolutionary biology , signal transduction , microbiology and biotechnology , arabidopsis , genetics , gene , mutant , philosophy , epistemology
Summary Strigolactones are an important class of plant signalling molecule with both external rhizospheric and internal hormonal functions in flowering plants. The past decade has seen staggering progress in strigolactone biology, permitting highly detailed understanding of their signalling, synthesis and biological roles – or so it seems. However, phylogenetic analyses show that strigolactone signalling mediated by the D14‐ SCF MAX 2 ‐ SMXL 7 complex is only one of a number of closely related signalling pathways, and is much less ubiquitous in land plants than might be expected. The existence of closely related pathways, such as the KAI 2‐ SMAX 1 module, challenges many of our assumptions about strigolactones, and in particular emphasises how little we understand about the specificity of strigolactone signalling with respect to related signalling pathways. In this review, we examine recent advances in strigolactone signalling, taking a holistic evolutionary view to identify the ambiguities and uncertainties in our understanding. We highlight that while we now have highly detailed molecular models for the core mechanism of D14‐ SMXL 7 signalling, we still do not understand the ligand specificity of D14, the specificity of its interaction with SMXL 7, nor the specificity of SMXL 7 function. Our analysis therefore identifies key areas requiring further study.