P-431 - Calcium oscillations associated with transcriptional noise reduction integrate cellular responses for quantitative disease resistance

Wednesday, July 16, 2025

13:30 - 15:15

Location: Confex Hall 3

Spatial & temporal resolution of the interaction interface

Author(s)

DJ

Darcy Jones

LIPME, INRAE - CNRS, Université de Toulouse, Castanet Tolosan, France
Castanet Tolosan, Midi-Pyrenees, France
FD

Florent Delplace

PostDoc
Laboratoire des Interactions Plantes-Microbes Environnement (LIPME), INRAE, CNRS, Université de Toulouse
Castanet-Tolosan, Occitanie, FRANCE
MK

Mehdi Khafif

Engineer
Laboratoire des Interactions Plantes-Microbes Environnement (LIPME), INRAE, CNRS, Université de Toulouse
Castanet Tolosan, Midi-Pyrenees, France
MZ

Matilda Zaffuto

LIPME, INRAE - CNRS, Université de Toulouse, Castanet Tolosan, France
Castanet Tolosan, Midi-Pyrenees, France
TX

Tou Cheu Xiong

IPSIM, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
Montpellier, Languedoc-Roussillon, France
AB

Adelin Barbacci

Researcher
Laboratoire des Interactions Plantes-Microbes Environnement (LIPME), INRAE, CNRS, Université de Toulouse
Castanet Tolosan, Midi-Pyrenees, France

Presenting Author(s)

SR

Sylvain Raffaele

Senior Researcher
LIPME, INRAE - CNRS, Université de Toulouse, Castanet Tolosan, France
Castanet Tolosan, Midi-Pyrenees, France

Efficient plant immune response requires concerted reprogramming of cellular transcriptomes both globally and locally at the site of infection. Upon inoculation by the fungal pathogen Sclerotinia sclerotiorum, plants show quantitative disease resistance (QDR) characterized by transcriptional reprogramming of numerous genes with small phenotypic effect. To study transcriptional heterogeneity across cells during QDR, we performed single-nucleus RNA-sequencing (snRNA-seq) of mock-treated and S. sclerotiorum inoculated Arabidopsis thaliana leaves. We observed cell type specific responses as well as a general reduction in transcriptional noise associated with QDR response. In animal tissues, the control of transcriptional noise by external signals emerges as a major lever to confer both stability and plasticity to gene regulation. Pathogen inoculation typically triggers systemic signaling in plant cells, including rapid intracellular calcium fluctuations. Using plants expressing the R-GECO1 reporter, we observed oscillations of calcium across whole leaves following fungal inoculation. Calcium spatial dynamics distinguished cell populations in good agreement with snRNA-seq clustering, suggesting that calcium may orchestrate transcriptional noise control upon pathogen challenge. Our results highlight the regulation of global transcriptional activity as a mechanism that could support both the cellular heterogeneity of QDR responses and their integration into a stable phenotype.