The receptor-like cytoplasmic kinase AeRLCK2 mediates Nod-independent rhizobial symbiosis in Aeschynomene legumes

2025

Article

Araújo N. H., Landry D., Quilbé J., Pervent M., Nouwen Nico, Klopp C., Cullimore J., Gully Djamel, Vicedo C., Gasciolli V., Brottier Laurent, Pichereaux C., Racoupeau M., Rios Maelle, Gressent F., Chaintreuil Clémence, Gough C., Giraud Eric, Lefebvre B., Arrighi Jean-François

Plant Cell, 2025, 37 (8), p. koaf201 [20 p.] ISSN 1040-4651

Many plants interact symbiotically with arbuscular mycorrhizal fungi to enhance inorganic phosphorus uptake, and legumes also develop a nodule symbiosis with rhizobia for nitrogen acquisition. The establishment and functioning of both symbioses rely on a common plant signaling pathway activated by structurally related Myc and Nod factors. Recently, a SPARK receptor-like kinase (RLK)/receptor-like cytoplasmic kinase (RLCK) complex was shown to be essential for arbuscular mycorrhiza formation in both monocot and dicot plants. Here, we show that in Aeschynomene legumes, the RLCK component of this receptor complex has undergone a gene duplication event and mediates a unique nodule symbiosis that is independent of rhizobial Nod factors. In Aeschynomene evenia, AeRLCK2 is crucial for nodule initiation but not for arbuscular mycorrhiza symbiosis. Additionally, AeRLCK2 physically interacts with and is phosphorylated by the cysteine-rich RLK, AeCRK, which is also required for nodulation. This finding uncovers an important molecular mechanism that controls the establishment of nodulation and is associated with Nod-independent symbiosis. The discovery of the receptor-like cytoplasmic kinase AeRLCK2 as being important for nodulation in Aeschynomene evenia sheds light on the molecular mechanisms of the Nod-independent symbiosis.

Sciences du monde végétal [076] ; Biotechnologies [084]

Fonds IRD [F B010094893]

fdi:010094893