Viola baoshanensis

an identified Cd hyperaccumulator can also tolerate and accumulate a certain amount of Pb. To understand the resistance/enrichment molecular mechanism of Viola baoshansis to Pb

suppression subtractive hybridization (SSH) was performed to screen gene segments induced by Pb

and semi-quantitive RT-PCR along with Northorn blotting was then used to verify the relationship between the screened expressed sequence tags (ESTs) and Pb tolerant/accumulation in V. baoshanensis. Twenty-seven different cDNA fragments were obtained via sequences analysis of cDNA inserts obtained from SSH subtractive cDNA library of V. baoshanensis roots. The results of both RT-PCR and Northern blot analysis showed that two cDNA fragments with high homology with xyloglucan endotransglycosylase (XTH) and GTP binding gene were up-regulated under Pb stress. It could be speculated that

in response to Pb stress

cell wall might have some changes and GTP binding protein might play a role in signal transduction.