Biology subjects

Deslandes-Herold, G.

Publications and source records attributed to Deslandes-Herold, G..

4 recordsLinked to original sources

bioRxiv2026

The plant immune receptor LORE binds agonistic and antagonistic 3-hydroxy fatty acid ligands via a dynamic loop in its G-type lectin domain

The Arabidopsis thaliana S-domain receptor kinase LORE senses bacterial medium-chain 3-hydroxy fatty acids (mc-3-OH-FAs) as microbe-associated molecular patterns to activate pattern-triggered immunity. How LORE recognises these fatty acid ligands at the molecular level remains unknown. Here, we combined protein structure prediction, protein-ligand interaction modelling and molecular dynamics (MD) simulations with ligand-binding assays using chimeric and mutant receptor ectodomains, and functional analysis of receptor activation to characterise the mc-3-OH-FA binding mechanism. Domain-swap experiments between LORE and its non-binding paralog AtSD1-23 identify the lectin 2 (L2) domain as the ligand-binding domain. Mutational analysis and reverse engineering confirm a hydrophobic pocket in the L2 core as the primary ligand-binding site. Multiple walker Supervised MD (mwSuMD) simulations reveal that the acyl tail enters the pocket first, whilst polar interactions between the headgroup and a flexible L2 loop guide and stabilise the bound state. In support of this model, 3-OH-C10:0 analogues with bulky headgroup modifications dock into the pocket but act as antagonists, presumably by preventing the loop from adopting the conformation required for signalling. Together, these data suggest that the flexible L2 loop has multiple functions: it acts as a dynamic gate regulating pocket access, provides essential anchoring points once the ligand is bound, and contributes to receptor activation. These findings provide a mechanistic framework for immunogenic mc-3-OH-FA sensing by LORE.

plant biology↗

bioRxiv2026

Diversification of ligand preference in conserved Brassicaceae LORE immune receptors matches proteobacterial 3-hydroxy fatty acid profiles

Pattern recognition receptors are often conserved across plant lineages, yet how ligand sensing diversifies during evolution remains poorly understood. The receptor kinase LORE mediates Arabidopsis thaliana immune responses to bacterial medium-chain 3-hydroxy fatty acids (mc-3-OH-FAs), but its distribution and functional variation across Brassicaceae remain largely unexplored. We combined phylogenetic analysis, species-wide immune profiling, ligand-binding assays, heterologous functional testing, and A. thaliana lore-1 complementation to define LORE diversification across Brassicaceae. LORE orthologs with conserved 3-OH-C10:0 binding are present in all major Brassicaceae lineages, including the basal lineage. Functional complementation confirmed mc-3-OH-FA-sensing capacity in orthologs spanning all four lineages. By contrast, chain-length preference profiles among mc-3-OH-FAs varied between species and orthologs, ranging from narrow 3-OH-C10:0-dominated profiles to broader profiles with comparable sensitivity to 3-OH-C10:0 and 3-OH-C12:0. 3-OH-FA profiling of a diverse collection of plant-associated bacteria revealed that high levels of mc-3-OH-FAs are prevalent in Proteobacteria, and that the range of mc-3-OH-FA chain lengths produced corresponds to the chain-length preferences of Brassicaceae LORE receptors. Our results establish LORE as a Brassicaceae-restricted pattern recognition receptor with conserved mc-3-OH-FA sensing but diversified chain-length preferences, and provide an evolutionary framework for studying how ligand preference can diversify within a biologically relevant ligand spectrum while core receptor function is maintained.

plant biology↗

bioRxiv2023

Bacterial tolerance to host-exuded specialized metabolites structures the maize root microbiome

Plants exude specialized metabolites from their roots and these compounds are known to structure the root microbiome. However, the underlying mechanisms are poorly understood. We established a representative collection of maize root bacteria and tested their tolerance against benzoxazinoids, the dominant specialized and bioactive metabolites in the root exudates of maize plants. In vitro experiments revealed that benzoxazinoids inhibited bacterial growth in a strain- and compound-dependent manner. Tolerance against these selective antimicrobial compounds depended on bacterial cell wall structure. Further, we found that native root bacteria isolated from maize tolerated the benzoxazinoids better compared to non-host Arabidopsis bacteria. This finding suggests the adaptation of the root bacteria to the specialized metabolites of their host plant. Bacterial tolerance to 6-methoxy-benzoxazolin-2-one (MBOA), the most abundant and selective antimicrobial metabolite in the maize rhizosphere, correlated significantly with the abundance of these bacteria on benzoxazinoid-exuding maize roots. Thus, strain-dependent tolerance to benzoxazinoids largely explained the abundance pattern of bacteria on maize roots. Abundant bacteria generally tolerated MBOA, while low abundant root microbiome members were sensitive to this compound. Our findings reveal that tolerance to plant specialized metabolites is an important competence determinant for root colonization. We propose that bacterial tolerance to plant-secreted antimicrobial compounds is an underlying mechanism determining the structure of host-specific microbial communities. Significance StatementDiverse microbial communities colonize plant roots. They feed on carbon rich root exudates which contain a diverse mix of chemicals including primary and specialized metabolites. Here we show that specialized metabolites act as selective antibiotics to shape the root bacterial communities. By growing single isolates of maize root bacteria in the presence of benzoxazinoids in vitro, we find that the strains differ greatly in their tolerance to benzoxazinoids. Their different levels of tolerance largely explained their abundance on benzoxazinoid-exuding roots. Our work shows how plant specialized metabolites act to shape the maize root microbial community and thus deepened our mechanistic understanding of how plants shape their microbiome.

microbiology↗

bioRxiv2022

Plant secondary metabolite-dependent plant-soil feedbacks can improve crop yield in the field

Plant secondary metabolites that are released into the rhizosphere alter biotic and abiotic soil properties, which in turn affect the performance of other plants. How such plant-soil feedbacks affect agricultural productivity and food quality in crop rotations is unknown. Here, we assessed the impact of maize benzoxazinoids on the performance, yield and food quality of three winter wheat varieties in a two-year field experiment. Following maize cultivation, we detected benzoxazinoid-dependent chemical and microbial fingerprints in the soil. The chemical fingerprint was still visible during wheat growth, while the microbial fingerprint was no longer detected. Benzoxazinoid soil conditioning by wild-type maize led to increased wheat emergence, tillering, growth and biomass compared to soil conditioning by bx1 mutant plants. Weed cover remained unaffected, while insect damage decreased in a subset of varieties. Wheat yield was increased by over 4% without a reduction in grain quality across varieties. This improvement was directly associated with increased germination and tillering. Taken together, our experiments demonstrate that plant secondary metabolites can increase yield via plant-soil feedbacks under agronomically realistic conditions. If this phenomenon holds across different soils and environmental conditions, optimizing plant root exudation could be a powerful, genetically tractable strategy to enhance crop yields without additional inputs.

plant biology↗