Fig. 5

Expression of phosphate transporters in P deficient poplars. a Heatmap of the relative expression of putative phosphate transporter genes in the three uppermost leaves and fine roots of poplar plants grown with different P concentrations in the nutrient solution (HP: 641 μM, MP: 6.4 μM, LP: 0.064 μM). Red colors indicate lower and yellow to white colors higher values after z-transformation of the transcript abundances of each gene across all analyzed tissues and P conditions. b Relative expression of selected PtPHTs measured by qRT PCR (mean ± SE). Values were normalized to the expression of two reference genes (Actin, PPR-repeat) in the samples. Different letters indicate significant differences in expression of each gene (adj. p ≤ 0.05, ANOVA and Tukey’s honest significance test, n = 3)