Biology subjects

Bernoux, M.

Publications and source records attributed to Bernoux, M..

3 recordsLinked to original sources

bioRxiv2025

Natural variation in an NLR pair confers thermostable resistance to a devastating bacterial pathogen

Climate change reshapes host-pathogen interactions by increasing pathogen aggressiveness and weakening plant immune responses, particularly under heat stress. Nucleotide-binding leucine-rich repeat (NLR) immune receptors, key players in pathogen recognition, are altered under elevated temperatures in both plants and mammals, posing a major challenge to disease resistance. In Arabidopsis thaliana, the well-described RPS4/RRS1 NLR pair confers resistance to the worldwide devastating phytopathogenic Ralstonia pseudosolanacearum. Here, by combining the exploration of natural genetic variation with genetic mapping, polymorphism analysis, structural modeling, and functional complementation, we demonstrated that the paucity of full thermostable resistance is primarily associated with a unique RPS4/RRS1 haplotype carrying key substitutions in leucine-rich repeat domains. These findings reveal natural genetic diversity as a source of thermostable resistance, highlighting promising opportunities to engineer climate-resilient plants.

plant biology↗

bioRxiv2024

Immune signaling induced by plant Toll/interleukin-1 receptor (TIR) domains is thermostable

Plant disease is a major threat in agriculture and climate change is predicted to intensify it. Above the optimal plants growth range, plant immunity and in particular immune responses induced by nucleotide-binding leucine rich repeat receptors (NLRs) are dampened, but the underlying molecular mechanisms remains elusive. NLRs usually contain an N-terminal signaling domain, such as Toll/interleukin-1 receptor (TIR) domain, which is self-sufficient to trigger immune signaling. By using inducible Arabidopsis transgenic lines expressing TIR-containing NLRs (TNLs) or corresponding isolated TIR domains from Arabidopsis RPS4 and flax L6 NLRs, we showed that immune signaling induced downstream of TNL activation is not affected by an elevation of temperature. Conditional activation of TNL- and isolated TIR-mediated immune responses follow the same signaling route at permissive temperature (EDS1/RNLs requirement and activation of the salicylic acid sector). Yet, this signaling pathway is maintained under elevated temperature (30{degrees}C) when induced by isolated TIRs, but not full-length TNLs. This work underlines the need to further study how NLRs are impacted by an increase of temperature, which is particularly important to improve the resilience of plant disease resistance in a warming climate.

plant biology↗

bioRxiv2023

Plant TIR domains physically interact with EDS1 family proteins to propagate immune signalling.

Plant Toll/interleukin-1 receptor/resistance protein (TIR) type nucleotide-binding and leucine-rich repeat immune receptors (NLRs) require Enhanced Disease Susceptibility 1 (EDS1) family proteins and the helper NLRs NRG1 and ADR1 for immune activation. TIR signalling domains possess NADase activity, producing NAM and v-cADPR from NAD+ in vitro. However, after TIR activation different small non-cyclic signalling molecules have been detected bound to EDS1/SAG101 and EDS1/PAD4 heterodimers. These molecules have not been detected in in vitro assays or as free molecules in planta and it is not clear how they are delivered to the EDS1 complexes. Here we investigate physical and functional interactions between TIR signalling domains, EDS1 family proteins and helper NLRs to clarify these signalling transduction pathways. We show that the NbEDS1-NbSAG101b-NbNRG1 signalling pathway in N. benthamiana is necessary and sufficient for cell death signalling induced by six different TIR-containing NLRs from a range of plant species, suggesting this module is likely a universal requirement for TIR-NLR mediated cell death in N. benthamiana. We also find that TIR domains physically interact with NbEDS1, NbPAD4 and NbSAG101 in planta, independently of each other. We also find evidence for direct interaction of NbNRG1 with NbSAG101b via its C-terminal EP domain, but not with other EDS1 family members. These data suggest a model in which physical interaction between activated TIRs and EDS1 signalling complexes facilitates efficient transfer of low abundance products of TIR catalytic activity directly to EDS1 heterocomplexes. The interaction could also alter TIR catalytic activity to favor production of the ligands recognised by EDS1/SAG101 and EDS1/PAD4.

plant biology↗