Biology subjects

Didelon, M.

Publications and source records attributed to Didelon, M..

3 recordsLinked to original sources

bioRxiv2024

Acclimation to high daily thermal amplitude converts a defense response regulator into susceptibility factor

Acclimation enables plants to adapt to immediate environmental fluctuations, supporting biodiversity and ecosystem services. However, global changes are altering conditions for plant disease outbreaks, increasing the risk of infections by pathogenic fungi and oomycetes, and often undermining plant immune responses. Understanding the molecular basis of plant acclimation is crucial for predicting climate change impacts on ecosystems and improving crop resilience. Here, we investigated how Arabidopsis thaliana quantitative immune responses acclimates to daily temperature fluctuations. We analyzed responses to the fungal pathogen Sclerotinia sclerotiorum following three acclimation regimes that reflect the distribution areas of both species. Mediterranean acclimation, characterized by broad diurnal temperature amplitudes, resulted in a loss of disease resistance in three natural A. thaliana accessions. Global gene expression analyses revealed that acclimation altered nearly half of the pathogen-responsive genes, many of which were down-regulated by inoculation and associated with disease susceptibility. Phenotypic analysis of A. thaliana mutants identified novel components of quantitative disease resistance following temperate acclimation. Several of these mutants were however more resistant than wild type following Mediterranean acclimation. Notably, mutant lines in the NAC42-like transcription factor did not show a loss of resistance under Mediterranean acclimation. This resistance was linked to an acclimation-mediated switch in the repertoire of NAC42-like targets differentially regulated by inoculation. These findings reveal the rewiring of immune gene regulatory networks by acclimation and suggest new strategies to maintain plant immune function in a warming climate.

plant biology↗

bioRxiv2021

Pathogen-derived mechanical cues regulate the spatio-temporal implementation of plant defense

How immune responses are activated and regulated is a central question in immunology. In addition to molecular signaling, recent work has shown that physical forces regulate the immune response of vertebrates by modifying transmembrane protein conformation and cell contact. Mechanical stress and strain produced by forces constitute physical cues perceived by cells instructing gene expression. Whether mechanical cues generated by pathogens during host colonization can trigger adaptive responses in plant cells remains elusive. We found that local and progressive variations of plant cell wall tension caused by fungal pathogen attacks are transmitted to neighboring healthy tissue around the infection site and trigger immunity in distal cells. This thigmoimmunity process requires the reorganization of cortical microtubules and contributes strongly to Arabidopsis disease resistance. One-Sentence SummaryActivation of plants immunity depends on fluctuations of mechanical tension caused by a fungal pathogen.

plant biology↗

bioRxiv2020

Genome-wide alternative splicing profiling in the fungal plant pathogen Sclerotinia sclerotiorum during the colonization of diverse host families

Sclerotinia sclerotiorum is a notorious generalist plant pathogen that threatens more than 600 host plants including wild and cultivated species. The molecular bases underlying the broad compatibility of S. sclerotiorum with its hosts is not fully elucidated. In contrast to higher plants and animals, alternative splicing (AS) is not well studied in plant pathogenic fungi. AS is a common regulated cellular process that increases cell protein and RNA diversity. In this study, we annotated spliceosome genes in the genome of S. sclerotiorum and characterized their expression in vitro and during the colonization of six host species. Several spliceosome genes were differentially expressed in planta, suggesting that AS was altered during infection. Using stringent parameters, we identified 1,487 S. sclerotiorum genes differentially expressed in planta and exhibiting alternative transcripts. The most common AS events during the colonization of all plants were retained introns and alternative 3' receiver site. We identified S. sclerotiorum genes expressed in planta for which (i) the relative accumulation of alternative transcripts varies according to the host being colonized and (ii) alternative transcripts harbor distinct protein domains. This notably included 42 genes encoding predicted secreted proteins showing high confidence AS events. This study indicates that AS events are taking place in the plant pathogenic fungus S. sclerotiorum during the colonization of host plants and could generate functional diversity in the repertoire of proteins secreted by S. sclerotiorum during infection.

genomics↗