Expression data from tobacco expressing 35S-AtHMA4 compared to the wild-type plants grown in the presence of Cd

Cd levels in the shoots, as well as in the roots were unexpectedly reduced in 35S:AtHMA4-expressing tobacco. Obtained results indicate that in the generation of the Cd-related phenotypes of transgenic plants substantial modifications of the host plant transcriptome was involved. Microarray based analysis was performed to compare expression profiles of the roots from tobacco expressing 35S-AtHMA4 with the wild-type (WT) plants, which were grown in the presence of 0.25 µM Cd. An effort was undertaken to understand which processes were modified in tobacco as a result of the expression of 35S:AtHMA4, which lead to decreased Cd uptake and lower accumulation in the shoots. Knowing underlying mechanisms is important for developing strategies to grow low cadmium tobacco. 4-week old tobacco plants (35S:AtHMA4 expressing and WT) were subjected to 0.25 µM Cd (added as CdCl2) for four days. Three independent experiments were performed. At the end of each experiment roots from six transgenic plants and six wild-type plants (excluding 1/3 of the distance from their base) were pooled, frozen in liquid nitrogen and stored until RNA isolation. Total RNA isolated from three batches of roots from each studied plant line, was used for three independent microarray analysis.