TY - JOUR

T1 - A glycan receptor kinase facilitates intracellular accommodation of arbuscular mycorrhiza and symbiotic rhizobia in the legume Lotus japonicus

AU - Kelly, Simon B.

AU - Hansen, Simon

AU - Rubsam, Henriette

AU - Saake, Pia

AU - Pedersen, Emil B.

AU - Gysel, Kira

AU - Madland, Eva T.

AU - Wu, Shunliang

AU - Wawra, Stephan

AU - Reid, Dugald

AU - Sullivan, John

AU - Blahovska, Zuzana B.

AU - Vinther, Maria L.

AU - Muszynski, Artur W.

AU - Azadi, Parastoo

AU - Thygesen, Mikkel R.

AU - Aachmann, Finn

AU - Ronson, Clive

AU - Zuccaro, Alga

AU - Andersen, Kasper R.

AU - Radutoiu, Simona

AU - Stougaard, Jens

PY - 2023

Y1 - 2023

N2 - Receptors that distinguish the multitude of microbes surrounding plants in the environment enable dynamic responses to the biotic and abiotic conditions encountered. In this study, we identify and characterise a glycan receptor kinase, EPR3a, closely related to the exopolysaccharide receptor EPR3. Epr3a is up-regulated in roots colonised by arbuscular mycorrhizal (AM) fungi and is able to bind glucans with a branching pattern characteristic of surface-exposed fungal glucans. Expression studies with cellular resolution show localised activation of the Epr3a promoter in cortical root cells containing arbuscules. Fungal infection and intracellular arbuscule formation are reduced in epr3a mutants. In vitro, the EPR3a ectodomain binds cell wall glucans in affinity gel electrophoresis assays. In microscale thermophoresis (MST) assays, rhizobial exopolysaccharide binding is detected with affinities comparable to those observed for EPR3, and both EPR3a and EPR3 bind a well-defined beta-1,3/beta-1,6 decasaccharide derived from exopolysaccharides of endophytic and pathogenic fungi. Both EPR3a and EPR3 function in the intracellular accommodation of microbes. However, contrasting expression patterns and divergent ligand affinities result in distinct functions in AM colonisation and rhizobial infection in Lotus japonicus. The presence of Epr3a and Epr3 genes in both eudicot and monocot plant genomes suggest a conserved function of these receptor kinases in glycan perception.

AB - Receptors that distinguish the multitude of microbes surrounding plants in the environment enable dynamic responses to the biotic and abiotic conditions encountered. In this study, we identify and characterise a glycan receptor kinase, EPR3a, closely related to the exopolysaccharide receptor EPR3. Epr3a is up-regulated in roots colonised by arbuscular mycorrhizal (AM) fungi and is able to bind glucans with a branching pattern characteristic of surface-exposed fungal glucans. Expression studies with cellular resolution show localised activation of the Epr3a promoter in cortical root cells containing arbuscules. Fungal infection and intracellular arbuscule formation are reduced in epr3a mutants. In vitro, the EPR3a ectodomain binds cell wall glucans in affinity gel electrophoresis assays. In microscale thermophoresis (MST) assays, rhizobial exopolysaccharide binding is detected with affinities comparable to those observed for EPR3, and both EPR3a and EPR3 bind a well-defined beta-1,3/beta-1,6 decasaccharide derived from exopolysaccharides of endophytic and pathogenic fungi. Both EPR3a and EPR3 function in the intracellular accommodation of microbes. However, contrasting expression patterns and divergent ligand affinities result in distinct functions in AM colonisation and rhizobial infection in Lotus japonicus. The presence of Epr3a and Epr3 genes in both eudicot and monocot plant genomes suggest a conserved function of these receptor kinases in glycan perception.

KW - MESORHIZOBIUM-LOTI

KW - DEFENSE RESPONSES

KW - PERCEPTION

KW - ROOT

KW - FUNGAL

KW - CELL

KW - EXOPOLYSACCHARIDE

KW - TRANSFORMATION

KW - LAMINARIN

KW - EVOLUTION

U2 - 10.1371/journal.pbio.3002127

DO - 10.1371/journal.pbio.3002127

M3 - Journal article

C2 - 37200394

VL - 21

JO - PLoS Biology

JF - PLoS Biology

SN - 1544-9173

IS - 5

M1 - 3002127

ER -