Global transcriptome of the fungal pathogen Sclerotinia sclerotiorum (strain 1980) during the colonization of 23 Accessions of Arabidopsis thaliana
Quantitative disease resistance (QDR) is an almost universal and often broad-spectrum process in plants, serving to limit the damage caused by pathogen infections. It represents the primary form of plant immunity that reduces disease symptoms induced by numerous pathogens actively killing host cells during infection, including the necrotrophic pathogen Sclerotinia sclerotiorum. Investigating the evolutionary origins of QDR against necrotrophic fungi is crucial for comprehending how plant resistance evolves. To explore the diversity of local responses to S. sclerotiorum within a plant species level, we conducted a comprehensive analysis of the entire transcriptomes from 23 accessions of Arabidopsis thaliana, mainly distributed across Europe. More than half on the pan-transcriptome displayed local responses toS. sclerotiorum, including similar transcriptome patterns. Notably, core S. sclerotiorum-responsive genes exhibited a clear gene age pattern, dominated by older genes forming protein-protein networks that continuously acquiring new hubs. Comparative transcriptome analyses revealed QDR is associated with quantitative expression variations specific to accession subsets. By comparison of promoter sequences, we have shown evidence that accession subsets independently evolved and acquired specific cis-regulatory elements, confering Sclerotinia resistance. This scenario suggests multiple exaptation trajectories of novel QDR genes through species-level cis-regulation. This study sheds light on the regulation of QDR-associated genes within a species, contributing to our understanding of the molecular mechanisms of plant fungal resistance. Overall design: Periphery of S. sclerotiorum disease lesions (Ss) and uninfected plants grown together (control), Ss and control samples collected simultaneously in three independent replicates