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Research article - Peer-reviewed, 2021

The Physcomitrium (Physcomitrella) patens PpKAI2L receptors for strigolactones and related compounds function via MAX2-dependent and -independent pathways

Lopez-Obando, Mauricio; Guillory, Ambre; Boyer, Francois-Didier; Cornu, David; Hoffmann, Beate; Le Bris, Philippe; Pouvreau, Jean-Bernard; Delavault, Philippe; Rameau, Catherine; Germain, Alexandre de Saint; Bonhomme, Sandrine


In angiosperms, the alpha/beta hydrolase DWARF14 (D14), along with the F-box protein MORE AXILLARY GROWTH2 (MAX2), perceives strigolactones (SL) to regulate developmental processes. The key SL biosynthetic enzyme CAROTENOID CLEAVAGE DIOXYGENASE8 (CCD8) is present in the moss Physcomitrium patens, and PpCCD8-derived compounds regulate moss extension. The PpMAX2 homolog is not involved in the SL response, but 13 PpKAI2LIKE (PpKAI2L) genes homologous to the D14 ancestral paralog KARRIKIN INSENSITIVE2 (KAI2) encode candidate SL receptors. In Arabidopsis thaliana, AtKAI2 perceives karrikins and the elusive endogenous KAI2-Ligand (KL). Here, germination assays of the parasitic plant Phelipanche ramosa suggested that PpCCD8-derived compounds are likely noncanonical SLs. (+)-GR24 SL analog is a good mimic for PpCCD8-derived compounds in P. patens, while the effects of its enantiomer (-)-GR24, a KL mimic in angiosperms, are minimal. Interaction and binding assays of seven PpKAI2L proteins pointed to the stereoselectivity toward (-)-GR24 for a single clade of PpKAI2L (eu-KAI2). Enzyme assays highlighted the peculiar behavior of PpKAI2L-H. Phenotypic characterization of Ppkai2l mutants showed that eu-KAI2 genes are not involved in the perception of PpCCD8-derived compounds but act in a PpMAX2-dependent pathway. In contrast, mutations in PpKAI2L-G, and -J genes abolished the response to the (+)-GR24 enantiomer, suggesting that PpKAI2L-G, and -J proteins are receptors for moss SLs.

Published in

Plant Cell
2021, volume: 33, number: 11, pages: 3487-3512

Authors' information

Lopez-Obando, Mauricio (Lopez Obando, Mauricio)
University Paris-Saclay
Swedish University of Agricultural Sciences, Department of Plant Biology
Vedas Corporación de Investigación e Innovación
Guillory, Ambre
Universite Paris Saclay
Boyer, Francois-Didier
Universite Paris Saclay
Cornu, David
Universite Paris Saclay
Hoffmann, Beate
Universite Paris Saclay
Le Bris, Philippe
Universite Paris Saclay
Pouvreau, Jean-Bernard
University of Nantes
Delavault, Philippe
University of Nantes
Rameau, Catherine
Universite Paris Saclay
Germain, Alexandre de Saint
Universite Paris Saclay
Bonhomme, Sandrine
Universite Paris Saclay

UKÄ Subject classification

Cell Biology

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