Proteome- and metabolome-level changes during early stages of clubroot infection in Brassica napus canola.

Clubroot is a destructive root disease of canola ( Brassica napus L.) caused by Plasmodiophora brassicae Woronin. Despite extensive research into the molecular responses of B. napus to P. brassicae , there is limited information on proteome- and metabolome-level changes in response to the pathogen, especially during the initial stages of infection. In this study, we have investigated the proteome- and metabolome- level changes in the roots of clubroot-resistant (CR) and -susceptible (CS) doubled-haploid (DH) B. napus lines, in response to P. brassicae pathotype 3H at 1-, 4-, and 7-days post-inoculation (DPI). Root proteomes were analyzed using nanoflow liquid chromatography coupled with tandem mass spectrometry (nano LC-MS/MS). Comparisons of pathogen-inoculated and uninoculated root proteomes revealed 2515 and 1556 differentially abundant proteins at one or more time points (1-, 4-, and 7-DPI) in the CR and CS genotypes, respectively. Several proteins related to primary metabolites ( e.g. , amino acids, fatty acids, and lipids), secondary metabolites ( e.g. , glucosinolates), and cell wall reinforcement-related proteins [ e.g. , laccase, peroxidases, and plant invertase/pectin methylesterase inhibitors (PInv/PMEI)] were identified. Eleven nucleotides and nucleoside-related metabolites, and eight fatty acids and sphingolipid-related metabolites were identified in the metabolomics study. To our knowledge, this is the first report of root proteome-level changes and associated alterations in metabolites during the early stages of P. brassicae infection in B. napus .