The negative regulator SMAX1 controls mycorrhizal symbiosis and strigolactone biosynthesis in rice.


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Article
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Authors
Choi, Jeongmin 
Servante, Emily K 
Abstract

Most plants associate with beneficial arbuscular mycorrhizal (AM) fungi that facilitate soil nutrient acquisition. Prior to contact, partner recognition triggers reciprocal genetic remodelling to enable colonisation. The plant Dwarf14-Like (D14L) receptor conditions pre-symbiotic perception of AM fungi, and also detects the smoke constituent karrikin. D14L-dependent signalling mechanisms, underpinning AM symbiosis are unknown. Here, we present the identification of a negative regulator from rice, which operates downstream of the D14L receptor, corresponding to the homologue of the Arabidopsis thaliana Suppressor of MAX2-1 (AtSMAX1) that functions in karrikin signalling. We demonstrate that rice SMAX1 is a suppressor of AM symbiosis, negatively regulating fungal colonisation and transcription of crucial signalling components and conserved symbiosis genes. Similarly, rice SMAX1 negatively controls strigolactone biosynthesis, demonstrating an unexpected crosstalk between the strigolactone and karrikin signalling pathways. We conclude that removal of SMAX1, resulting from D14L signalling activation, de-represses essential symbiotic programmes and increases strigolactone hormone production.

Description
Keywords
Arabidopsis, Arabidopsis Proteins, Furans, Gene Expression Regulation, Plant, Germination, Heterocyclic Compounds, 3-Ring, Homozygote, Intracellular Signaling Peptides and Proteins, Lactones, Multigene Family, Mycorrhizae, Oryza, Phylogeny, Plant Proteins, Plant Roots, Pyrans, RNA-Seq, Signal Transduction, Symbiosis
Journal Title
Nat Commun
Conference Name
Journal ISSN
2041-1723
2041-1723
Volume Title
11
Publisher
Springer Science and Business Media LLC
Rights
All rights reserved
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/P003419/1)
Bill & Melinda Gates Foundation (OPP1172165)
Isaac Newton Trust Leverhulme Trust EMBO Bill & Melinda Gates Foundation Marie-Curie Fellowships ERC