Biology subjects

Landry, D.

Publications and source records attributed to Landry, D..

3 recordsLinked to original sources

bioRxiv2025

EPP1 couples receptor activation to cytoplasmic signaling in root nodule symbiosis

Legume symbiosis with nitrogen-fixing bacteria is controlled by a cascade of signaling events leading to root nodule development. While plant cell-surface receptors initiate this process, the link between receptors and cytoplasmic signaling components remains unclear. Here we identify Early Phosphorylated Protein 1 (EPP1) as a central mediator of this pathway. EPP1 is recruited to the activated SYMRK receptor, where it is phosphorylated on a key serine residue, an event essential and sufficient to propagate symbiotic signaling. We provide structural and functional validation of the SYMRK-EPP1 signaling complex and demonstrate that EPP1 is required for root nodule formation. Synthetic engineering of the SYMRK-EPP1 interaction bypasses the need for symbiotic bacteria to initiate the pathway and triggers nodule organogenesis. These findings establish EPP1 as a crucial cytoplasmic component between receptor activation and intracellular signaling, advancing our understanding of nitrogen-fixing symbiosis.

plant biology↗

bioRxiv2024

A Receptor Like Cytoplasmic Kinase evolved in Aeschynomene legumes to mediate Nod-independent rhizobial symbiosis

Many plants interact symbiotically with arbuscular mycorrhizal (AM) fungi to enhance inorganic phosphorus uptake, and legumes also develop a nodule symbiosis with rhizobia for nitrogen acquisition. 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 AM in both monocot and dicot plants. Here, we show that in Aeschynomene legumes the RLCK component of this receptor complex has evolved following 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 AM. Additionally, AeRLCK2 physically interacts with and is phosphorylated by the Cysteine-rich RLK, AeCRK, also required for nodulation. This work reveals a novel evolutionary origin of this Nod-independent symbiosis from AM.

plant biology↗

bioRxiv2021

An NLR Integrated Decoy toolkit to identify plant pathogen effector targets

Plant resistance genes (or NLR "Nod-like Receptors") are known to contain atypical domains procuring them with a decoy capacity. Some of these integrated domains (or ID) allow the plant to lure the virulence determinants ("effectors") of pathogens and triggering a specific NLR immune reaction. In this work, our goal was to generate a library of known IDs that could be screened with plant pathogen effectors in order to identify putative new effector virulence targets and NLR-effector pairs. We curated the IDs contained in NLRs from seven model and crop plant species. We cloned 52 IDs representing 31 distinct Pfam domains. This library was screened for interaction by yeast-two-hybrid with a set of 31 conserved Ralstonia solanacearum type III effectors. This screening and the further in planta interaction assay allowed us to identify three interactions, involving different IDs (kinase, DUF3542, WRKY) and two type III effectors (RipAE and PopP2). PopP2 was found to physically interact with ID#85, an atypical WRKY domain integrated in the GmNLR-ID85 NLR protein from Soybean. Using a imaging method in living plant cells, we showed that PopP2 associates with ID#85 in the nucleus. But unlike the known WRKY-containing Arabidopsis RRS1-R NLR receptor, this newly identified soybean WRKY domain could not be acetylated by PopP2 and its atypical sequence (WRKYGKR) also probably renders it inefficient in plant immunity triggering. This ID toolkit is available for screening with other plant pathogen effectors and should prove useful to discover new effectors targets and potentially engineer new plant resistance genes.

plant biology↗