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Arbuscular mycorrhizal fungi possess a CLAVATA3/embryo surrounding region‐related gene that positively regulates symbiosis
Author(s) -
Le Marquer Morgane,
Bécard Guillaume,
Frei dit Frey Nicolas
Publication year - 2019
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.15643
Subject(s) - medicago truncatula , symbiosis , biology , rhizophagus irregularis , gene , botany , embryo , endosymbiosis , arbuscular mycorrhizal fungi , microbiology and biotechnology , arbuscular mycorrhizal , genetics , inoculation , bacteria , plastid , chloroplast , immunology
Summary The arbuscular mycorrhizal (AM) symbiosis is a beneficial association established between land plants and the members of a subphylum of fungi, the Glomeromycotina. How the two symbiotic partners regulate their association is still enigmatic. Secreted fungal peptides are candidates for regulating this interaction. We searched for fungal peptides with similarities with known plant signalling peptides. We identified CLAVATA (CLV)/EMBRYO SURROUNDING REGION (ESR)‐RELATED PROTEIN (CLE) genes in phylogenetically distant AM fungi: four Rhizophagus species and one Gigaspora species. These CLE genes encode a signal peptide for secretion and the conserved CLE C‐terminal motif. They seem to be absent in the other fungal clades. Rhizophagus irregularis and Gigaspora rosea CLE genes ( RiCLE1 and GrCLE1) are transcriptionally induced in symbiotic vs asymbiotic conditions. Exogenous application of synthetic RiCLE1 peptide on Medicago truncatula affects root architecture, by slowing the apical growth of primary roots and stimulating the formation of lateral roots. In addition, pretreatment of seedlings with RiCLE1 peptide stimulates mycorrhization. Our findings demonstrate for the first time that in addition to plants and nematodes, AM fungi also possess CLE genes. These results pave the way for deciphering new mechanisms by which AM fungi modulate plant cellular responses during the establishment of AM symbiosis.