Periodic Reporting for period 4 - IMMUNO-PEPTALK (Regulation of plant receptor kinase-mediated immunity by endogenous peptides and their receptors)
Período documentado: 2022-12-01 hasta 2023-11-30
The second objective aimed at deciphering the formation, composition, and function of plasma membrane (PM) immune receptor nanoclusters. We showed that FER localizes to PM nanoclusters and regulates the lateral mobility of FLS2 and BAK1 within PM nanoclusters (Gronnier et al., eLife 2022). In collaboration with colleagues in France, we showed that FER regulates the localization of PM phosphatidylserine to regulate stress signaling (Smokvarska et al., Science Adv., 2023).
The third objective aimed to reveal the function of the LRR-receptor kinase MIK2 and its ligand(s) in immunity. Having identified MIK2 as the receptor for SCOOP peptides (Rhodes et al., Nature Comm. 2021), we now showed that the SCOOP family is much larger than anticipated (50 members) and identified the subtilases cleaving PROSCOOP proteins to generate bioactive peptides (Yang et al., Nature Plants, 2023; Rhodes & Zipfel, Methods Mol. Biol., 2024). Progress is being made to decipher MIK2 signaling in different pathways. In particular, we could identify that a single SCOOP peptide is linked to MIK2’s function in cell wall damage response (Zhai et al., in preparation), and we have identified several SCOOPs that might be involved in salt and drought responses. Finally, we recently pioneered a computational approach, combining phylogenomics and AI-based protein structural modeling, to infer the binding mechanisms of SCOOPs to MIK2 (Snoeck et al., bioRxiv 2024).
Furthermore, based on their transcriptional up-regulation upon immune signaling (like SCOOPs), we identified a novel family of phytocytonines conserved in Angiosperms, CTNIPs, and their cognate receptor, the LRR-RK HSL3 (Rhodes et al., eLife 2022). The characterization of CTNIPs and HSL3 is other plant species, such as grasses, legumes and Solanaceae is currently ongoing, as well as the analysis of Arabidopsis CTNIP-related peptides that we also identified based on bioinformatics searches.
1. Deciphering of RALF-binding mechanisms to FER (and other MLRKs) ((Xiao, Stegmann, Han et al., Nature 2019).
2. Genome-wide re-annotation and characterization of the RALF family in Arabidopsis ((Abarca et al., Plant Physiol. 2021; Fernández-Fernández, Abarca et al., in prep.).
3. Demonstration that FER regulates the nanoscale plasma membrane dynamics of immune receptor complexes (Gronnier et al., eLife 2022).
4. Identification of SCOOPs as MIK2 ligands, characterization of their perception mechanisms and roles in diverse signaling pathways (Rhodes et al., Nature Comm. 2021; Yang et al., Nature Plants, 2023; Snoeck et al., bioRxiv 2024; Zhai et al., in prep.).
5. Identification of CTNIP-HSL3 as a novel conserved stress responsive peptide-receptor module (Rhodes et al., eLife 2022).
A number of additional results are still being prepared for publication.