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Comparative Ralstonia solanacearum dynamics and metabolomic profiling of advanced potato clones with different levels of bacterial wilt resistance.

Maria Siri: Bioscience Department, School of Chemistry, Universidad de la Republica

<div>Bacterial wilt caused by <em>Ralstonia solanacearum</em> is responsible for substantial losses in cultivated potato crops worldwide. Breeding for bacterial wilt resistance is a major challenge for disease control, especially in regions where the pathogen is endemic. A potato breeding program is conducted in Uruguay based on the introgression of resistance from the wild native species <em>Solanum commersonii</em>. In this work we report the characterization of advanced potato clones with different levels of bacterial wilt resistance. First, we performed the comparison of pathogen colonization and dissemination patterns after plant inoculation with <em>R. solanacearum </em>fluorescent and luminescent reporter strains. Resistant clones showed colonization only in roots and the stem base suggesting that resistance in potato is achieved through restriction of bacterial invasion and multiplication in stems. In addition, we performed a metabolomic profiling of roots, stems, leaves and xylem sap based on NMR analysis. Plant samples were collected from non-inoculated plants and from plants soil-inoculated with <em>R. solanacearum </em>at 7 dpi. ¹H-NMR spectra of plant metabolites were acquired and subjected to multivariate analyses, allowing differentiation among infected and non-infected plants. The relationship between the metabolite profiles and resistance was also explored. This study paves the way for understanding potato resistance to <em>R. solanacearum </em>and for the identification of relevant metabolites involved in this plant-pathogen interaction.</div>