Proteins in the Xylem Exudate from Brassica napus L. Response to Cadmium Treatment

Abstract

Cadmium (Cd) is a toxic heavy metal. Accumulation of Cd in the soil of cultivated field causes serious damage for crops. In order to eliminate Cd effectively from contaminated soil by plants, Cd should be transported to shoot organs. Cd is supposed to be transported to shoot organs via xylem. In this study, we investigated responses of proteins in the xylem exudate from Brassica napus L. to Cd treatment.
Plants were grown hydroponically in a greenhouse and were treated with Cd (10µM, 30µM). Xylem exudate was collected after cutting stems approximately 2 cm above the root. Proteins in the exudate were analyzed.
Protein concentration in the exudate was about 13µg/mL. The SDS-PAGE analysis demonstrates that the protein composition in these exudates was distinctly different from that in the extracts from leaves, roots, stems and in the phloem exudates. Proteins of 20kDa and 45kDa increased and 50kDa-protein decreased by Cd treatment.