Comparative Proteomic Analysis in Clubroot-Susceptible and Resistant Cabbage Inbred Lines

The clubroot disease of Brassicaeae is caused by the obligate biotroph, Plasmodiophora brassicae. It is one of the most damaging pathogen within this plant family and is difficult to control by chemical or cultural means. The aim of the study is to understanding of the B.oleracease-P. brassicae interaction during the early phases of infection. The clubroot- susceptible (CT-18) and resistant (YCR) breeding lines of cabbage were subjected to proteomics-based approaches with 2-D IEF/SDS–PAGE. Proteins were extracted from aerial part of CT-18 and YCR cabbage plants at 5 days after root inoculation with P. brassicae or buffer and separated with 2-D IEF/SDS–PAGE. A subset of forty-eight proteins were identified in at least two biological replicates and exhibited significantly altered expression between mock and P. brassicae treatments and/or in the two inbred lines. The identified proteins involved in oxidative stress, ABA metabolism, glucose mediated signaling, response to stimulus. The resistant YCR line expressed higher levels of ABA responsive protein and fructose-bisphosphate aldolase and glucose sensor interaction protein than CT-18 in both mock- and P. brassicae treated samples, suggesting that these proteins may provide a basal defense against P. brassicae infection in YCR. Specifically, we observed that susceptible (CT-18) line expressed higher levels of cobalamin-independent methionine synthase than YCR, which may result in the susceptibility of the host prior to gall formation in root. Further works with identified proteins will facilitate the identification of key molecular determinants for improving club root disease resistance by cabbage crop species.