A Brachypodium distachyon LysM-RLK recognizes arbuscular mycorrhizal symbiotic signals
A. GIRARDIN (1), M. Cumener (1), L. Buendia (1), G. Virginie (1), R. Sibout (2), M. Dalmais (3), A. Bendahmane (3), B. Lefebvre (1) (1) Laboratory of Interaction Plant Microorganisms (LIPM) - INRA/CNRS, France; (2) INRA-Agro Paris Tech, France; (3) Univ. Paris 11-Univ. Evry-Univ. Paris7-CNRS-INRA, France

Arbuscular mycorrhizal (AM) fungi colonize roots of most land plants allowing them better access to nutrients. AM fungi secrete lipo-chitooligosaccharides (LCOs) and chitooligosaccharides (COs), called Myc-factors. LCOs that are called Nod factors are also produced by rhizobial bacteria, which form another root endosymbiosis with legume plants. Myc factors and Nod factors activate the common symbiosis signaling pathway that is required for both the AM and the rhizobia/legume symbioses. Nod factors are essential for establishment of nodulation. In contrast, the role of Myc factors in the AM is not yet known, although they induce molecular and developmental responses on diverse plant species. Our project aims to better understand the roles of Myc factors. To do this, we are searching for their receptors in plants. Proteins encoded by the Lysin-Motif Receptor-Like Kinase (LysM-RLK) family are candidates for LCO and CO receptors. Brachypodium distachyon, a monocotyledon, is a promising model since it has a reduced number of LysM-RLKs compared to other mycorrhizal plants with sequenced genomes. Here, we show that the LysM-RLK BdLYR1 selectively binds LCOs with a high affinity. To determine its role in the AM, we are currently analyzing mutated B. distachyon lines obtained by CRISPR or TILLING. Marker genes for Myc factor responsiveness in B. distachyon have been identified by RNAseq analysis, and will be used for phenotyping the bdlyr1 mutants in addition to mycorrhization tests.

Abstract Number: P2-25
Session Type: Poster