Identification of proteins in susceptible and resistant Brassica oleracea responsive to Xanthomonas campestris pv. campestris infection.

UNLABELLED: Cruciferous plants are important edible vegetables widely consumed around the world, including cabbage, cauli-flower and broccoli. The main disease that affects crucifer plants is black rot, caused by Xanthomonas campestris pv. campestris (Xcc). In order to better understand this specific plant-pathogen interaction, proteins responsive to Xcc infection in resistant (União) and susceptible (Kenzan) Brassica oleracea cultivars were investigated by 2-DE followed by mass spectrometry. A total of 47 variable spots were identified and revealed that in the susceptible interaction there is a clear reduction in the abundance of proteins involved in energetic metabolism and defense. It was interesting to observe that in the resistant interaction, these proteins showed an opposite behavior. Based on our results, we conclude that resistance is correlated with the ability of the plant to keep sufficient photosynthesis metabolism activity to provide energy supplies necessary for an active defense. As a follow-up study, qRT-PCR analysis of selected genes was performed and revealed that most genes showed an up-regulation trend from 5 to 15days after inoculation (DAI), showing highest transcript levels at 15DAI. These results revealed the gradual accumulation of transcripts providing a more detailed view of the changes occurring during different stages of the plant-pathogen interaction. BIOLOGICAL SIGNIFICANCE: In this study we have compared cultivars of Brassica oleracea (cabbage), susceptible and resistant to black rot, by using the classical 2-DE approach. We have found that resistance is correlated with the ability of the plant to keep sufficient photosynthesis metabolism activity to provide energy supplies necessary for an active defense.