P-026 - Dissecting early interactions in potato wart disease using transcriptome analysis

Potato wart disease, caused by quarantine pathogen Synchytrium endobioticum, significantly impacts agriculture by reducing yields. Without visible mycelium and over 40 pathotypes of this elusive pathogen, understanding of the pathosystem is crucial. We utilized transcriptome analysis to study early interactions in resistant 'Karolin' and susceptible 'Spunta' potato varieties post-infection with S. endobioticum pathotype 18 across multiple time points. Remarkably, significant changes in gene expression were detected as early as five hours post-infection: In 'Karolin', genes linked to immune responses, including kinase and receptor activities, were activated. By 4 days post-inoculation (dpi), the susceptible variety 'Spunta' displayed first signs of fungal proliferation while the resistant variety 'Karolin' sustained a multifaceted defensive strategy. Later processes such as oxidative stress management and chitinase activity were detected, underscoring robust defence activation. Transcriptomic shifts in 'Spunta', imply an energy diversion to growth over defence. Tracing fungal secretome expression in addition, our findings reveal an immediate interplay of host and microbe. These findings demonstrate an immediate metabolic reprogramming to counteract the pathogen and lay a foundation for breeding efforts aimed at enhancing potato resistance.