Responses of the grass Paspalum distichum L. to Hg stress: A proteomic study.

Paspalum distichum L. was tested to evaluate its ability to phytoremediate mercury (Hg) contaminated soil over a 60-d period by analysis of the total Hg concentrations in roots and leaves. Hg concentration in Hg-contamination soil decreased by 70.0 μg g⁻¹ after 60 day of grass cultivation and Hg was readily taken up by the roots (4.51 ± 1.90 μg g⁻¹) rather than the leaves (0.35 ± 0.02 μg g⁻¹). In addition, a comparative proteomic study was performed to unravel the protein expression involved in the Hg stress response in P. distichum L. A total of 49 proteins were classified as differentially proteins in the roots by the 'top three' proteomic analysis, of which 32 were up-regulated and 17 down-regulated in response to Hg stress. These changed proteins were classified by gene ontology analysis into five complex molecular functions involving photosynthesis and energy metabolism (31%), oxidative stress (14%), protein folding (16%), sulfur compound metabolism (10%), metal binding, and ion transport (29%). Moreover, the protein expression patterns were consistent with the metabolism pathway results. Overall, the results contribute to our understanding of the molecular mechanisms of the Hg response in P. distichum and we propose a theoretical basis for the phytoremediation of Hg-contaminated soils. Image 1 • Forty nine abundant proteins were identified in the roots of P. disctichum. L. • Five kind proteins of P. disctichum. L were classified under the Hg stress condition. • During the plant cultivation process, mercury content in soil decreased by 31.3%. • Mercury in roots and shoots of P. distichum. L increased by 10.0 and 5.83 times. Mercury could be bioaccumulated in Paspalum distichum L and the proteomic study showed 32 proteins were up-regulated and 17 proteins were down-regulated in response to Hg stress in the roots. [ABSTRACT FROM AUTHOR]